University of Catania Department of Physics - Documents

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University of Catania
Department of Physics
Corso Italia, 57 – I 95129 Catania – Italy – Tel.: +39.95.71.95.111 – FAX: +39.95.38
TELEX: 971554 INFNCT I
1997 ANNUAL REPORT
April 18, 2005
Contents
1 INTRODUCTION
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2 DIRECTION
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3 FACULTY STAFF
3.1 DEPARTMENT’S PROFESSORS (including RETIREES) . .
3.2 DEPARTMENT’S RESEARCHERS . . . . . . . . . . . . . .
3.3 RESEARCHERS AFFILIATED WITH OTHER AGENCIES .
3.4 TECHNICIANS AND ADMINISTRATIVES . . . . . . . . . .
3.5 RESEARCH FELLOWS . . . . . . . . . . . . . . . . . . . . .
3.6 FOREIGN GUESTS . . . . . . . . . . . . . . . . . . . . . . .
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4 COURSES HELD IN ACADEMIC YEAR 1996/1997
”LAUREA” IN PHYSICS PROGRAMME
(equivalent to MASTER OF SCIENCES)
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5 PHYSICS COURSES FOR OTHER ”LAUREA” PROGRAMMES
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6 ”DOTTORATO DI RICERCA”
(equivalent to Ph.D.)
IN PHYSICS PROGRAMME
6.1 PhD Activities . . . . . . . . .
6.1.1 X cicle . . . . . . . . . .
6.1.2 XI cicle . . . . . . . . .
6.1.3 XII cicle . . . . . . . . .
6.1.4 XIII cicle . . . . . . . .
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7 ”DOTTORATO DI RICERCA”
IN MATERIAL SCIENCE PROGRAMME
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7.0.5 XII cicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
8 PARTNERSHIPS, SPECIAL PROJECTS AND NETWORKS
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9 EMSPS
European Mobility Scheme for Physics Student
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10 AREA A : APPLIED PHYSICS
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10.1 Thermal regimes in soil solarization process . . . . . . . . . . . . . . . . . 30
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10.2 Electrochromic windows and mirrors with modulated transmittivity or reflectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.3 LANDIS: Laboratory of Non Destructive Analysis . . . . . . . . . . . . .
10.4 Physical methodologies applied to the environmental and cultural heritage
10.5 DSI and FUZZY Collaborations . . . . . . . . . . . . . . . . . . . . . . .
10.6 GeSi materials and devices . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.7 Helium Implantation: voids, gettering and oxide formation . . . . . . . . .
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11 AREA B: EXPERIMENTAL NUCLEAR AND PARTICLE PHYSICS
11.1 CMS Collaboration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.2 Study of the giant dipole resonance in very ho nuclei . . . . . . . . . . . .
11.3 Study of the production mechanism of hard photons and energetic protons
11.4 Fusion and Binary-decay mechanism in the 35 Cl+24 Mg system at E/A ≈ 8
MeV/nucleon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.5 Statistical binary decay of 35 Cl +24 M g at ≈8 MeV/nucleon . . . . . . . .
11.6 Fission Decay of 48 Cr at E∗CN ≈60 MeV . . . . . . . . . . . . . . . . . . .
11.7 Heavy-ion reactions at Tandem energy . . . . . . . . . . . . . . . . . . . .
11.8 Fission of targetlike nuclei produced by bombarding haevy nuclei with light
projectile at the tandem energy . . . . . . . . . . . . . . . . . . . . . . . .
11.9 Deformed configurations in 24 M g at high excitation energy . . . . . . . . .
11.10Isospin role on nuclear structure and on nuclear collision properties . . . .
11.11A new monolithic silicon detector telescope . . . . . . . . . . . . . . . . . .
11.12Particle-gamma coincidence measurements: effect of the particle selection
on the γ-spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.13Preequilibrium gamma ray emission in heavy ion collisions . . . . . . . . .
11.14Particle-gamma coincidence measurements for the study of the GDR gammadecay; results from the TRASMA apparatus at Tandem and cyclotron energies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.15Elastic scattering and fusion process for the system p +1 2C . . . . . . . .
11.16The short-lived 8 Be level at Ex =11.4 MeV . . . . . . . . . . . . . . . . . .
11.17Photonuclear reactions with tagged and polarized gamma beam . . . . . .
11.18Experiment E938H at LBNL (TRANSPORT Collaboration) . . . . . . . .
11.19Experiment E987H at LBNL (EOS Collaboration) . . . . . . . . . . . . . .
11.20Experiment E896 at BNL (H0 Collaboration) . . . . . . . . . . . . . . . .
11.21ALICE Collaboration . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.22Low energy reactions and features of light nuclei . . . . . . . . . . . . . . .
11.23The CMS Experiment at CERN’s LHC . . . . . . . . . . . . . . . . . . . .
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12 AREA C: THEORETICAL PHYSICS
12.1 C1: THEORETICAL NUCLEAR PHYSICS . . . . . . . . . . . . . . . .
12.1.1 Risonanze giganti . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.1.2 Dinamica delle fluttuazioni e frammentazione nucleare . . . . . . .
12.1.3 Fenomeni critici in sistemi finiti . . . . . . . . . . . . . . . . . . . .
12.1.4 Descrizione semiclassica della fusione sotto barriera e della fissione.
12.1.5 Chaotic dynamics in nuclear multifragmentation . . . . . . . . . . .
12.1.6 Chaoticity and dissipation of nuclear collective motion . . . . . . .
12.1.7 Anharmonicities and non-linearities in the excitation of Double Giant Resonances . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.1.8 Collective transition densities in neutron-rich nuclei . . . . . . . . .
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12.3
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12.5
12.6
12.1.9 Universal behavior of Lyapunov exponents in unstable systems:
”Critical Chaos”. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.1.10 Semiclassical methods in heavy-ion chaotic scattering . . . . . . . .
12.1.11 Finite Size Effects in QGP . . . . . . . . . . . . . . . . . . . . . . .
12.1.12 Parton Modification Effects in Heavy Ion Collisions, . . . . . . . . .
12.1.13 Parton Distributions and J/Ψ Suppression, . . . . . . . . . . . . . .
12.1.14 Structure of Odd-A 1s0d and 1p0f-shell nuclei in the Collective Pair
Approximation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.1.15 QRPA and beta decay physics: higher-order approximations in a
boson formalism . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.1.16 Torwards a self-consistent Random Phase Approximation for Fermi
systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.1.17 Superfluidity of Nuclear Matter with realistic forces . . . . . . . . .
12.1.18 Equation of State of Nuclear Matter . . . . . . . . . . . . . . . . .
12.1.19 Transport Model of Heavy Ion Collisions . . . . . . . . . . . . . . .
12.1.20 Astrophysical S(E) factor at very low energy: screening effect or
nuclear effect? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THEORETICAL PARTICLE PHYSICS . . . . . . . . . . . . . . . . . . .
12.2.1 Phenomenology at LEP . . . . . . . . . . . . . . . . . . . . . . . .
12.2.2 Scalar Theories on Lattice . . . . . . . . . . . . . . . . . . . . . . .
THEORETICAL SOLID STATE PHYSICS . . . . . . . . . . . . . . . . .
12.3.1 Polaronic theories in discrete systems with reduced dimensionality .
12.3.2 Interplay between correlation and disorder in electronic systems. . .
12.3.3 Statistical models for molecular ordering. . . . . . . . . . . . . . . .
12.3.4 High Tc Superconductors . . . . . . . . . . . . . . . . . . . . . . . .
12.3.5 Molecular Systems under High Pressure . . . . . . . . . . . . . . .
12.3.6 Correlations in Molecular Systems . . . . . . . . . . . . . . . . . . .
12.3.7 Ionization and Excitation Energies of Molecules and Microcluster .
C4 - GENERAL ARGUMENTS IN THEORETICAL PHYSICS . . . . . .
12.4.1 Multiscale Expansions and Integrability . . . . . . . . . . . . . . . .
12.4.2 Explicit Solutions of Model Evolution Equations in 2+1 Dimensions
12.4.3 Linear Theories and their Symmetries . . . . . . . . . . . . . . . . .
C5 - INTERDISCIPLINAR SUBJECTS . . . . . . . . . . . . . . . . . . .
12.5.1 Discrete Geometry and Integrability . . . . . . . . . . . . . . . . . .
C6 - GENERAL ARGUMENTS IN THEORETICAL PHYSICS . . . . . .
12.6.1 Tunnelling times . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.6.2 Quantum Chaos . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13 AREA D: SOLID STATE PHYSICS
13.1 High temperature superconductivity . . . . . . . . . . . . . . .
13.2 D - Analysis of measurements criteria of acoustic urban noise
13.3 Electrochromic materials . . . . . . . . . . . . . . . . . . . . .
13.4 Interfaces and oxidation states. . . . . . . . . . . . . . . . . .
13.5 Catalysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.6 Clusters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.7 Erbium Luminescence in Silicon . . . . . . . . . . . . . . . . .
13.8 High energy implantation and defects . . . . . . . . . . . . . .
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14 AREA E: GENERAL PHYSICS
14.1 Fractal clustering in seismicity temporal distribution (1989-1994) of the
low eastern flank of Mt. Etna . . . . . . . . . . . . . . . . . . . . . . . .
14.2 Multimedia software packages and their test in the teaching of Physics
(both in university courses and in secondary school) . . . . . . . . . . . .
14.3 Study of the newtonian analysis of circular motion in relation to the writings of Descartes and Huygens, . . . . . . . . . . . . . . . . . . . . . . .
14.3.1 Cultural exploitation of the ancient scientific material (instruments,
books, reviews, etc.) owned by the Department of Physics and the
Astrophysical Observatory of Catania, . . . . . . . . . . . . . . .
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15 Publications in APPLIED PHYSICS 1996
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16 Publications in EXPERIMENTAL NUCLEAR AND PARTICLE PHYSICS
1996
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17 Publications in THEORETICAL PHYSICS 1996
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18 Publications in SOLID STATE PHYSICS 1996
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19 Publications in GENERAL PHYSICS 1996
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20 Publications in APPLIED PHYSICS 1997
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21 Publications in EXPERIMENTAL NUCLEAR AND PARTICLE PHYSICS
1997
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22 Publications in THEORETICAL PHYSICS 1997
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23 Publications in SOLID STATE PHYSICS 1997
24 ACTIVITY OF TECHNICAL AND AMINISTRATIVE
24.1 ACCOUNTING OFFICE . . . . . . . . . . . . . . . . . .
24.2 VAN DE GRAAFF ACCELERATOR . . . . . . . . . . . .
24.3 CRYOGENICS . . . . . . . . . . . . . . . . . . . . . . . .
24.4 ELECTRONICS . . . . . . . . . . . . . . . . . . . . . . .
24.5 ION IMPLANTATION . . . . . . . . . . . . . . . . . . . .
24.6 MECHANICAL SHOP . . . . . . . . . . . . . . . . . . . .
24.7 VACUUM . . . . . . . . . . . . . . . . . . . . . . . . . . .
24.8 LASER LABORATORY . . . . . . . . . . . . . . . . . . .
24.9 COMPUTER CENTRE . . . . . . . . . . . . . . . . . . .
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SERVICES
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Chapter 1
INTRODUCTION
The Physics Department is a methodologic one, where most of the research and teaching activities in the field of Physics conducted at Univeristy of Catania take place. Most
Professors of the courses for the Degree (”Laurea”) in Physics are members of the Department. Many of them teach courses for other Degrees of the Science Faculty and of other
Faculties. Professors and Researchers of the Department are currently 68. Technicians
and Administrative Personnel amount to 36.
The Department hosts the PhD in Physics programme.
The Department features a Library and its own Administrative and Technical Services.
The Department hosts:
• [1] the local Section of INFN (Istituto Nazionale di Fisica Nucleare), whose personnel
work in close collaboration with Department members, in the fields of Nuclear and
Sub-Nuclear Physics
• [2] the local Section of INFM Istituto Nazionale di Fisica per la Materia), for research
in the field of Condensed Matter and Molecular Physics
• [3] the Sicilian Centre for Nuclear and Solid State Physics (CSFNSM), which sponsors research in interdisciplinary fields of Physics.
Several members of the Department have been instrumental in realizing the National
Southern Laboratory (LNS) of INFN, which is located in Catania. They conduct research
activity at this Laboratory.
Other Department members conduct research at the CNR’s Institute for Microelectronics Methodologies and Techniques, which operates in close collaboration with the
research department of the SGS-Thompson Company, a microelecrtonics manifacturer
whose plant is located in Catania.
For the purpose of organizing this report, the research activity of the Physics Department has been divided into 5 categories: 1) Applied Physics, 2) Experimental Nuclear
Physics, 3) Theoretical Physics, 4) Solid State Physics, 5) Miscellaneous Activities of
General Physics. Each category includes several fields. Moreover, some researches belong
to more than one category.
The publication list included in this report is only partial, as it does not include a
large number of Contributions to national and international Conferences and Schools,
magazine reports, non-specialistic scientific papers, technical notes, etc.
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Chapter 2
DIRECTION
DIRECTOR
LO NIGRO Salvatore
Director Board [Giunta]
ARENA Nicoló
Vice Director
BAERI Pietro
BARBERA Roberto
CUNSOLO Angelo
DI TORO Massimo
GIANSIRACUSA Giuseppe
GRIMALDI Maria Grazia
MAZZEO Carmela
RUSSO Giuseppe
Un componente la Commissione del Personale
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Chapter 3
FACULTY STAFF
3.1
DEPARTMENT’S PROFESSORS (including RETIREES)
AGODI Attilio
ARENA Nicoló
BAERI Pietro
BARBARINO Sebastiano
BELLIA Giorgio
BELLINI Vincenzo
BURRAFATO Giuseppe
CAMPISANO Salvatore Ugo
CATARA Francesco
CAVALLARO Salvatore
CAVALLARO Sebastiano
CUNSOLO Angelo
DI TORO Massimo
EBERLE Enrico
FARACI Fiuseppe
FIGUERA Antonino Silva
FONTE Giacomo
FOTI Antonino
FOTI Gaetano
GIANSIRACUSA Giuseppe
GIORDANO Roberto
GUTKOWSKI Diego
IMMÉ Giuseppina
INSOLIA Antonio
LATTUADA Marcello
LOMBARDO Umberto
LO NIGRO Salvatore
MIGNECO Emilio
NOTARRIGO Salvatore
PAPPALARDO Giuseppe
PARISI Rosa
PENNISI Agata Raffaella
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PORTO Francesco
POTENZA Renato
PUCCI Renato
RACITI Giovanni
RIGGI Francesco
RIMINI Emanuele
RUSSO Giovanni Valerio
RUSSO Giuseppe
SAMBATARO Salvatore
SANTINI Paolo Maria
SCALIA Augusto
STRAZZERI Andrea
TROJA Sebastiano Olindo
TURRISI Elio
VINCIGUERRA Domenico
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DEPARTMENT’S RESEARCHERS
ALBERGO Sebastiano
BARBERA Roberto
CASTORINA Paolo
COSTA Salvatore
COSTANZO Evelina
GIUSTOLISI Francesco
GRIMALDI Maria Grazia
LO MONACO Luigi
MACCARRONE Gaetano Daniele
PAPPALARDO Lorenzo
PAPPALARDO Salvatore
PICCITTO Giovanni
PRIOLO Francesco
REITANO Riccardo
RIZZO Francesca
SIMONE Francesca
SIRINGO Fabio
SPERDUTO Maria Leda
TERRASI Antonio
TOMASELLO Pasquale
TUVÉ Cristina
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3.3
RESEARCHERS AFFILIATED WITH OTHER
AGENCIES
I.N.F.N. RESEARCH PERSONNEL - CATANIA
AIELLO Sebastiano
BADALÀ Angela
BALDO Marcello
BURGIO Fiorella
CARDELLA Giuseppe
CONSOLI Maurizio
FONTE Roberto
ITALIANO Antonino (Messina)
LANZA Giuseppe Edoardo
LANZANÒ Gaetano
PAGANO Angelo
PALMERI Armando
PAPA Massimo
PAPPALARDO Giuseppe Salvatore
PIRRONE Sara
RAPISARDA Andrea
SAMBATARO Michelangelo
SUTERA Concetta Maria
C.N.R. RESEARCH PERSONNEL
COFFA Salvatore
IACONA Fabio
LA VIA Francesco
LOMBARDO Salvatore
PENNISI Agostino
PRIVITERA Vittorio
RAINERI Vito
SPINELLA Rosario Corrado
C.S.F.N.S.M. RESEARCH PERSONNEL
FRISONE Fulvio
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3.4
TECHNICIANS AND ADMINISTRATIVES
• DEPARTMENT’S ADMINISTRATION
1. FORMICA L.
2. GIUFFRIDA G.
3. MAZZEO C. (Segretario Amministrativo)
4. RUBULOTTA G. (RESAIS)
• ACCOUNTING OFFICE
1. FORTUNA L.
2. NICOTRA N.
3. RAPICAVOLI M. R.
• TEACHING SERVICES
1. AULINO G.
2. D’ARRIGO S.
3. D’URSO F.
4. FERLITO P.
5. GAROZZO C.
6. PARASOLE V.
7. PETTA C.
• GENERAL SERVICES
1. COSENTINO S.
2. FINOCCHIARO S. (RESAIS)
• LABORATORIES
1. LA CHINA C.
2. LA ROCCA A.
3. LEOTTA S.
4. MARINO N.
5. PARASOLE O.
6. SALEMI M. (INFN)
7. TROVATO A.
• ELECTRONICS SERVICES
1. D’ANDREA M. (INFN)
2. FICHERA F. (INFN)
3. GIUDICE N.
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4. GUARDONE N.
5. LIBRIZZI F. (INFN)
6. NICOTRA D. (INFN)
7. REITO S. (INFN)
8. SACCA’ G. (INFN)
9. URSO S. (INFN)
• LIBRARY
1. MURÈ G.
2. PLUCHINO S.
• COMPUTER CENTRE
1. BELLUOMO P. (INFN)
2. CANGIANO E. (INFN)
3. ROCCA C. (INFN)
4. SAVA G. (INFN)
• TECHNICAL SERVICES
1. ARRIVA F.
2. CONTI O. (INFN)
3. LO FARO S. (INFN)
4. MAZZEO M.
5. PLATANIA B.
6. RAPICAVOLI A.
7. RAPICAVOLI C. (INFN)
8. RIZZA G. (INFN)
9. SPARTI V. (INFN)
10. TIMPANARO G.
• SPECIAL TASKS
1. BRUNO G. (CNR)
2. CONNELLI V. (CNR)
3. DI BIASI G.
4. POLI G.
5. SANTORO A. (INFN)
6. SCUDERI V.
• RECEIVING & STORES
1. LEOTTA S.
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2. PELLICANE M. (INFN)
• C.S.F.N.S.M. ADMINISTRATION
1. D’ARRIGO A. M.
2. SCOLLO M. R.
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3.5
RESEARCH FELLOWS
ANDRONICO Giuseppe
BARLETTA Giacomo
BARONE TONGHI Letizia
BASSI Massimo Savino
CALIGIORE Claudio
CAPUTA Concetta
CHERUBINI Silvio
COSENTINO Luigi
FRANZÒ Giorgia
LA MAGNA Antonino
LI ROSI Daniele
LO PRESTI Domenico
MACCARRONE Salvatore
MUSUMECI Paolo
NOCIFORO Chiara
PALAZZOLO Francesco
POLITI Giuseppe
SALESI Giovanni
SCHULZE Hans Josef
TRICOMI Alessia
VIOLA Alessandra
ZAPPALÀ Dario
Università
INFM
CSFNSM
CRRNSM
CRRNSM, INFN
CRRNSM
CRRNSM
CRRNSM
CNR
INFM, CNR
CRRNSM
INFN
CRRNSM
INFM
CRRNSM, INFN
CRRNSM
INFN
Università
INFN
INFN
CSFNSM
Università
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3.6
FOREIGN GUESTS
• ALLES Bartolome - Italy - (INFN)
• ANDRES Maria Victoria - Spain - (INFN)
• BAUER Wolfang - Germany • BLASCHKE David - Germany - (INFN)
• BRANCHINA Vincenzo - France - (INFN)
• CATURLA Maria Jose - Spain • DINH DANG Nguyen - Japan - (INFN)
• DORST Claudio - Argentina • DULINSKI Wojciech - France - (INFN)
• FERREIRA Lidia - Portugal - (INFN)
• FLORESCU Adrian - Romania • HAMAMOTO Kuroda ikuko - Japan • HO Mae Wan - U.K. - (INFN)
• HOLLIK Wolfgang - Germany - (INFN)
• JARCZYK Lucjan - Poland - (INFN)
• KOUZNETOV Andrej - Russia • KWASNIEWCIZ Edward - Poland - (INFN)
• LARIONOV Alexej - Russia • LINSLEY John - New Mexico USA - (INFN)
• LIOTTA Roberto Juan - Sweden - (INFN)
• MACHNER Harmut Kurt - Germany - (INFN)
• MAGIERA Andrzej - Poland - (INFN)
• MAKHTARI Abdel - Marocco - (INFN)
• MARCH Norman Henry - U.K. - (INFN)
• MICALLEF Joseph - Malta • NASIROV Avazbek - Russia - (INFN)
• PIAECKI Ernest - Poland - (INFN)
• ROBNIK Marko - Jugoslavia - (INFN)
15
• ROUSSEL-CHOMAZ Patricia - France - (INFN)
• SAGAIDAK Roman - Russia - (INFN)
• SAGAWA Hiroyuki - Japan • SANDULESCU Nicolae - Romania - (INFN)
• SCHRAMM David Norma - USA - (INFN)
• SCHWARZ Camsten - Germany - (INFN)
• SONG Hongqiu - China - (INFN)
• SIBIRTSEV Alexandre - Russia - (INFN)
• SOIC Neven - Croazia • STEVENSON Paul - USA - (INFN)
• STRATAN George - Romania • TAKAHASHI Yoshiyuki - USA - (INFN)
• TAKAOKA Gikan - Japan • THÖNNENSSEN Michael Rober - Germany
• VOLANT Claude - France - (INFN)
• WANG Qi - China • WINFIELD John Stuart - U.K. - (INFN)
• YEREMIN Alexandre - Russia - (INFN)
• ZHANG Yi-Jun - China • ZUO Wei - China • ZVEREV Michail - Russia - (INFN)
16
Chapter 4
COURSES HELD IN ACADEMIC
YEAR 1996/1997
”LAUREA” IN PHYSICS
PROGRAMME
(equivalent to MASTER OF
SCIENCES)
ANALISI MATEMATICA I o
ANALISI MATEMATICA II o
ASTROFISICA
ASTRONOMIA
CALCOLO ELETTRONICO
CHIMICA
COMPLEMENTI DI FISICA GENERALE
ELETTRONICA APPLICATA
ESPERIMENTAZIONI DI FISICA I
ESPERIMENTAZIONI DI FISICA II
ESPERIMENTAZIONI DI FISICA III
FISICA DELL’AMBIENTE
FISICA DEI DISPOSITIVI ELETTRONICI
FISICA DEI MATERIALI
FISICA DEI SEMICONDUTTORI
FISICA DELLO SPAZIO
FISICA DELLO STATO SOLIDO
FISICA GENERALE I
FISICA GENERALE II
FISICA MOLECOLARE
FISICA NUCLEARE
FISICA SOLARE
FISICA STELLARE
FISICA SUPERIORE
FISICA TEORICA
FISICA TERRESTRE
17
GEOMETRIA
ISTITUZIONI DI ASTROFISICA
ISTITUZIONI DI FISICA NUCLEARE E SUBNUCLEARE
ISTITUZIONI DI FISICA TEORICA
LABORATORIO DI ASTRONOMIA
LABORATORIO DI ELETTRONICA
LABORATORIO DI FISICA DELL’AMBIENTE
LABORATORIO DI FISICA DELLA MATERIA
LABORATORIO DI FISICA NUCLEARE
MECCANICA RAZIONALE
MECCANICA STATISTICA
METODI MATEMATICI DELLA FISICA
METODOLOGIE FISICHE PER I BENI CULTURALI
PREPARAZIONE ESPERIENZE DIDATTICHE
RADIOASTRONOMIA
RADIOATTIVITÀ
REAZIONI NUCLEARI
SPETTROSCOPIA
SPETTROSCOPIA NUCLEARE
STORIA DELLA FISICA
STRUTTURA DELLA MATERIA
TEORIA DEI CAMPI
TEORIA DEI SISTEMI A MOLTI CORPI
18
Chapter 5
PHYSICS COURSES FOR OTHER
”LAUREA” PROGRAMMES
CAMPI ELETTROMAGNETICI
CORSO INTEGRATO DI FISICA PER MEDICINA E CHIRURGIA I
CORSO INTEGRATO DI FISICA PER MEDICINA E CHIRURGIA II
CORSO INTEGRATO DI FISICA PER MEDICINA E CHIRURGIA III
DISPOSITIVI ELETTRONICI PER INGEGNERIA ELETTRONICA
ESERCITAZIONI DI FISICA SPERIM. PER CHIM. E CHIM. IND.
FISICA GENERALE I PER MATEMATICI
FISICA GENERALE II PER MATEMATICI
FISICA PER SCIENZE NATURALI
FISICA PER FARMACIA
FISICA PER CHIMICA E TECN. FARM. (CTF)
FISICA I PER SCIENZE GEOLOGICHE
FISICA II PER SCIENZE GEOLOGICHE
FISICA I PER SCIENZE DELL’INFORMAZIONE
FISICA II PER SCIENZE DELL’INFORMAZIONE
FISICA PER SCIENZE BIOLOGICHE
FISICA SPERIM. II PER CHIMICI
FISICA I PER ING. MECCANICA
FISICA II PER INGEGNERIA ELETTRICA
FISICA PER MEDICINA - ODONTOIATRIA LABORATORIO DI FISICA PER SCIENZE BIOLOGICHE
MICRO ONDE
19
Chapter 6
”DOTTORATO DI RICERCA”
IN PHYSICS PROGRAMME
The Physics Department is the main hub for the activities of the PhD in Physics at
University of Catania. Available PhD majors are:
• [1] Nuclear Physics
• [2] Solid State Physics
• [3] Theoretical Physics
• [4] Astrophysics
Although funds granted by University of Catania have been particularly meager, an intense activity has been organized, including lecture courses and special seminars, held
also by foreign Scholars. The possibility for students to conduct part of their research at
foreign Universities or Laboratories has been preserved.
Collaboration with other local research Institutions helps students fulfill their research
goals. These Institutions include the Institute of Physics of the Engeneering Faculty, the
Astrophysics Observatory, The Institute of Astronomy, all of the University of Catania,
as well as INFN and CNR.
In the fall 1997 the final graduation exam for PhD students of the IX cicle has
taken place in Roma. All candidates partecipated successfully. Dr. Z. Caccia and Dr.
S. Panebianco requested an one-year prolongation.
In 1997 the X cicle has been in its third year (students: F. Amorini, D. Boemi,
M. Cabibbo, S. Libertino, S. Messina, A. Pagliaro, A. Tricomi, M. Trovato, and G. Verde);
the XI cicle has been in its second year (students:A.L. Aliotta, G. Angilella, C. Aramo,
C.S. Buemi, M. Carbonaro, G. Cinà, A.M. Gueli, G. Lanzalone, E. Paladino );
the XII cicle has been in its first year (students: A. Alberti, L. Borrello, I. Busà, F.
Cappuzzello, M. Gulino, G. Marino, G. Riccobene, F.P. Romano, C. Sfienti, S. Tudisco,
A. Tumino).
20
6.1
PhD Activities
6.1.1
X cicle
Coordinators: F. Catara, (M. Di Toro)
Teacher Staff: A. Agodi, G. Belvedere, C. Blanco, A. Cunsolo, M. Di Toro, G. Faraci,
G. Giaquinta, S. Lo Nigro, M. Rodonò, C. Spitaleri, S.O. Troja.
Students of X cicle, thei thesis work and tutor were:
1. F. AMORINI: ”Emissione di raggi di preequilibrio nelle collisioni
58
N i +45 Sc ad energie intermedie”.
58
N i +51 V e
(Tutor: G. Pappalardo)
2. D. BOEMI:” Danneggiamento da radiazione in rivelatori microstrip di silicio per il
Central Tracker di CMS”.
(Tutor: G.V. Russo)
3. M. CABIBBO: ” Aspetti di equilibrio e non equilibrio in collisioni tra ioni pesanti”.
(Tutor: G. Pappalardo)
4. Z. CACCIA (IX cicle):” Rivelazione di neutroni in collisioni tra ioni pesanti ad
energie relativistiche”.
(Tutor: R. Potenza)
5. S. LIBERTINO:” Role of impurities on the electrical and optical properties of ion
implanted silicon”.
(Tutor: E. Rimini)
6. S. MESSINA:” Long and short-term fotometric variability af late-type stars”.
(Tutors: G. Cutispoto, M. Rodonò)
7. A. PAGLIARO:” Inward clusters of galaxies”
(Tutor: V. Antonuccio)
8. S. PANEBIANCO (IX cicle):” Memorie analogiche VLSI a condensatori commutati
per il rivelatore a deriva di silicio”.
(Tutor: G.V. Russo)
9.
10. A. TRICOMI:” Asimmetria Avanti-Indietro dei quark pesanti in interazioni e+ e−
al LEP (Esperimento ALEPH)”
(Tutor: R. Potenza)
11. M. TROVATO:” Applicazione della termodinamica estesa per la descrizione del
trasporto di carica per i portatori caldi nel silicio”.
(Tutor: M. Anile)
12. G. VERDE:” Curva calorica nucleare”
(Tutor: G. Immè)
21
6.1.2
XI cicle
Coordinators: F.Catara (M. Di Toro)
The thesis topics of the students of XI cicle are as follows:
1. M.L. ALIOTTA:” Metodi diretto ed indiretto per lo studio della reazione 12 C(α, γ)16 O
ad energie di interesse astrofisico”.
(Tutors: C. Spitaleri, R.A. Zappalà)
2. G. ANGILELLA:” Superconduttori ad alta temperatura critica”.
(Tutor: R. Pucci)
3. C. ARAMO:” Ricostruzione dello sviluppo longitudinale della componente adronica
di sciami atmosferici estesi”.
(Tutors: R. Fonte, M.Ambrosio [Napoli])
4. C.S. BUEMI:” Osservazione coordinata multibanda di AR Lac ed interpretazione
dei fenomeni di attività stellare”.
(Tutor: M. Rodonò)
5. M. CARBONARO:” Transizioni di fase strutturali termodinamiche in sistemi finiti”.
(Tutor: M. Baldo)
6. G. CINÀ:” Collisioni tra ioni pesanti ad energie relativistiche”.
(Tutors: R. Potenza, S. Costa)
7. A.M. GUELI:” Processi di luminescenza stimolata: misure integrali e spettroscopiche,
applicazioni”.
(Tutor: S.O. Troja)
8. G. LANZALONE:” Studio di reazioni profondamente inelastiche tra ioni pesanti ad
energie intermedie con rivelatori a 4π”.
(Tutor: F. Porto)
9. E. PALADINO:” Proprietà di trasporto di sistemi di elettroni fortemente correlati
a bassa dimensionalità”.
(Tutor: G. Giaquinta)
6.1.3
XII cicle
Coordinators: F.Catara, (M. Di Toro)
Each student of the XII cicle has attended three of the following scheduled courses,
according to the chosen curriculum:
1. Fisica Nucleare (Coord. M. Ditoro, G. Raciti)
22
2. Fisica Subnucleare (Coord. P. Castorina, A. Palmeri)
3. Fisica Statistica (Coord. M. Baldo)
4. Fisica dei Materiali (Coord. E. Rimini)
5. Spettroscopia (Coord. G. Faraci)
6. Spettroscopia Stellare (Coord. A. Lanzafame)
7. Magnetoidrodinamica (Coord. C. Blanco)
6.1.4
XIII cicle
Procedures to operate this cicle in 1997 have been started.
23
Chapter 7
”DOTTORATO DI RICERCA”
IN MATERIAL SCIENCE
PROGRAMME
Consorziato con il Dipartimento di Chimica dell’Università di Catania e i Dipartimenti
di Fisica e di Chimica dell’Università di Padova.
7.0.5
XII cicle
Coordinator: S.U. Campisano
The students of XII cicle are:
1. Diego Boscarino. (Tutor: Prof. Mazzoldi)
2. Giovanni Mannino (Tutor: Prof. S.U. Campisano)
3. Enrico Napolitani (Tutor: Prof. Carnera)
4. Bruno Pignataro (Tutor: Prof. G. Marletta)
5. Rosaria Puglisi (Tutor: Prof. S.U. Campisano)
6. Marco Ruzzi (Tutor: Prof. Corvaja)
24
Chapter 8
PARTNERSHIPS, SPECIAL
PROJECTS AND NETWORKS
1. Progetto nazionale finanziato dal CNR su:
”Studio di sistemi molecolari in condizioni estreme di temperatura e pressione”.
Istituti coinvolti:
Dip. Catania, Dip. Roma, Firenze, IEQ Firenze, ISM Roma.
2. Convenzione di collaborazione scientifica tra:
Dipartimento di Fisica di Catania,
Istituto Nazionale di Fisica Nucleare,
Universitá Jaghellonica di Cracovia
Universitá Silesiana di Katowice.
3. Progetto finanziato dalla CEE su:
”Ion Beam of Semiconductors”.
Istituti coinvolti:
VDTC.DPAP, FZR, UCTA.DF, FHG.AIS, IMEC, VAAR.IPA,
CNRS.PHASE, MPG.IKPHY, UTHESS.PD, CNR.ICTMLE.
4. Progetto Finanziato dalla CEE su:
”Heterostructures on Si for integrated Optoelictronics”.
CNR/IESS (coordinatore), FORTH.ICE, CNRS.CRMCZ, URTV.DF, UCTA.DF,
UVGO.FISA, FORTH.IESL, CNRS.LEPES, UIADN.EMAT, ENEA.IS, NRCSD.IM.
5. Collaborazione finanziata dalla CEE (contratto n. ERBFMBICT961042) tra il Dipartimento di Fisica dell’Università di Catania e il Departamento de Fisica Atomica,
Molecular y Nuclear, Universidad de Sevilla (Spagna).
25
6. Contratto di ricerca scientifica tra:
Dipartimento di Fisica Università Catania e CORIMME CT su:
”Impianti ad alta energia di B e di Al in campioni strutturati”, ”Caratterizzazione
elettrica e strutturale di strati SIPOS”, ”Controllo della vita media di portatori
minoritari tramite impianti di Pt”.
7. Contratto di Ricerca scientifica tra:
Dipartimento di Fisica Università di CT e SGS Thomson Microelectronics - Agrate
Brianza (MI)
”Studio degli impianti ad alta energia”, ”Microscopia elettronica”.
8. Convenzione tra il Dipartimento di Fisica dell’Università di Catania e la Ditta ”Enna
Ambiente”, per misure suilivelli di inquinamento da radiazioni ionizzanti nell’ambito
esterno di 4 miniere dismesse nella provincia di Enna.
9. Convenzione tra il Dipartimento di Fisica dell’Università di Catania e il CNR IMETEM, nell’ambito del ”Progetto SCOOP”.
10. Convenzione tra il Dipartimento di Fisica dell’Università di Catania e l’Istituto
Nazionale di Fisica Nucleare.
11. Convenzione tra il Dipartimento di Fisica dell’Università di Catania e l’Istituto
Nazionale di Fisica per la Materia.
26
Chapter 9
EMSPS
European Mobility Scheme for
Physics Student
Our Department is involved in the EMSPS, the European Mobility Scheme for Physics
Students. An explanatory note to the history and aims of the convention is given below.
• 1) Youth exchange and mobility of students in particular are now generally recognized as a promising means to further international understanding. For Europe,
with its recent epoch-making political developments, it will represent an important element in the promotion of cooperation and integration. It also takes into
consideration the aspiration of the young generation open to the world.
• 2) Several supranational organizations, notably the Council of Europe and UNESCO, have established conventions with a view to encourage the mobility of students in Europe. The European Community (EC) has adopted its pioneering programme ERASMUS, which recently has been extended to the European Free Trade
Association (EFTA) countries. EC has also set up its programme TEMPUS with
the aim to further student mobility with regard to Central/Eastern Europe (C/EE).
• 3) A certain number of physics students in Europe benefit right now from these
programmes, mainly in the framework of Inter-university Cooperation Programmes
(ICP) of ERASMUS. Exchange is however limited to students from those institutions
which are involved in ICP’s in physics. The overall fraction of students who have
access to such programmes is therefore rather small.
• 4) For this reason, and in view of the political developments mentioned above, it
SEEMED timely to envisage a mobility scheme that will, in principle, be open to
physics students from all institutions from all of Europe. The European Physical
Society (EPS) has decided to propose to European institutions giving an academic
degree in physics (universities and equivalent institutions) to set up together such
a scheme. EPS has long-standing experience in promoting cooperation among European physicists, including those from C/EE countries.
• 5) After the preliminary proposal of April 1991, EPS has consulted the relevant
institutions in October 1991 in more detail, sending them a draft convention and a
questionnaire. More than 150 positive replies have been returned, confirming thus
27
the substantial interest among institutions from all of Europe for such a scheme.
The Mobility Working Group has then adapted the Convention, taking into account
the comments received. This new version of the Convention, dated 28 March 1992,
has been approved by the Council of EPS who at the same time has taken the formal
decision to launch the scheme.
• 6) The aim of the mobility scheme is the following: a) to allow physics students
of all of Europe to spend, if they desire, and under certain conditions, a ”mobility
period” of study in another institution, called the ”host institution”, and b) to
ensure that such a period will be recognized when the student comes back to his
”home institution”, subject of course to the student’s satisfactory performance.
Other key elements of the scheme are its openness to all institutions who desire
to participate, and from all of Europe. It is intended as a permanent scheme,
governed by a Convention to which the institutions are committed. The scheme is
based on mutual trust regarding all academic aspects. It requires no adaptation or
harmonization of the curricula, nor of the courses given or of their content.
• 7) One essential element of the scheme is that the full academic responsibility for
the student remains with the home institution. It is therefore only from this home
institution that the student will get his final degree. In view of this responsibility,
it is up to the home institution to select the students which may benefit from the
scheme and to establish the relevant conditions. The role of the host institution, on
the other hand, is to offer its courses (i.e. the courses it gives anyhow for its own
students) and to assess the performance of the student according to the established
programme. Participating institutions must also be prepared to take a number of
practical measures in order to facilitate the exchange of students, notably regarding
counselling, language preparation, housing, and mobility grants.
• 8) Each institution may determine the number of students it is willing to accept
in a given year, and it may impose particular requirements. As a corollary, each
institution shall not send out more of its own students than it is willing to accept.
However a precise balanced flow is not strived for, and not probable to take place
anyhow.
• 9) The practical functioning of the scheme relies heavily on the devotion of the ”coordinators”, in both the home and the host institutions. They advise the students
on all academic and practical aspects and help to solve the arising problems. Coordinators also play an important role on the level of the overall scheme: a Mobility
Committee has been formed, having coordinators as its members, which decides on
the practical organization, in particular the flow of information and the deadlines.
• 10) In view of the choice of the host institution, and the preparation of the study
programme, students and coordinators must have access to the relevant information
(on academic and practical matters) regarding all participating institutions. This
documentation is available through a remote-access computerized database, located
at the Physics Department of the University of Manchester.
• 11) ”Mobility grants” for students (meant to cover additional expenses) are essential
for promoting mobility. Applications for such grants to ERASMUS and TEMPUS
have been filed. Hopefully, institutions will ask for and obtain complementary means
on a national or local basis.
28
• 12) The scheme has been realized as follows:
– a) In April 1992 the Convention was sent to all institutions having expressed
their interest in the scheme, asking them to return a ”request of adherence
letter”.
– b) In June 1992 the Mobility Committee was formed by enlarging the former
Working Group so as to achieve a balanced representation of the various countries participating in the scheme. The Mobility Committee has advised EPS
on the acceptance of the institutions for participation in the scheme, elaborated the guidelines for the flow of information, and called on the help of
Coordinating Institutions for the applications to ERASMUS and TEMPUS.
– c) In October 1992 the institutions having applied have been informed on the
acceptance in the scheme and were asked to provide the relevant academic
and practical information regarding their institution. For the academic year
1993/94 122 institutions from 25 countries all over Europe are involved in the
scheme.
– d) In October 1992 an application has been filed with ERASMUS for funding
of the scheme as an Inter-University Cooperation Project (ICP) and it was
accepted; altogether 94 institutions from 16 EC and EFTA countries are involved. A similar request has been submitted in January 1993 to TEMPUS for
a Joint European Project (JEP); here, besides the EC countries, only Hungary
and Latvia could participate in 1993/94.
– e) Work on the preparation of the database has continued so that it has been
ready for input from participating institutions and fully operational since January 1993.
– f) In spring 1993 interested students were able to consult the database, choose
their host institution, and establish the study programme to which the Coordinator was to give his approval. The student’s file has then been transmitted
to the host institution which has the obligation to rapidly inform the student
on acceptance or refusal. Around 100 students take part in this exchange
programme during the academic year 1993/94.
– g) In autumn 1993 accepted students began studies abroad and the scheme
became operational.
• 13) Further information on the scheme may be obtained from Dr. Catia Petta.
Since the year 1997 the Program Erasmus has been changed in the Program Socrates.
29
Chapter 10
AREA A : APPLIED PHYSICS
10.1
Thermal regimes in soil solarization process
G.Burrafato, D.Gutkowski
Soil solarization is a technique to reduce the incidence of soilborne agents of plant
disease, which takes advantage of the soil temperature increase obtained by mulching
wetted soil in summer. Considerable physical implications concern th e study of the
optical transmittance and the infrared reflectance of mulching film, the temperature field
at various depths and its evolution in time. Our work is devoted to evaluate the apparent
thermal diffusivity of the soil near the surface by measuring both the soil In order to
perform a laboratory control of the biological, chemical and physical aspects involved in
such process, a device simulating thermal regimes of soil solarization was realized. The
system is composed by a cubic box of 0.343 m3 of internal volume with lateral walls
thermally insulated which can be filled by soil of interest. The bottom is coupled by an
alluminum plate coil to a thermocryostat which ensures a constant temperature at the
depth of 70 cm as measured in the field. The top is coupled with a stainless steel plate
heating coil in which is flowing a liquid whose temperature is controlled by a programmable
thermostat. The cooling rate of the upper plate coil is controlled.
10.2
Electrochromic windows and mirrors with modulated transmittivity or reflectivity
A. Pennisi, F. Simone
L’attività di ricerca riguarda la realizzazione e la caratterizzazione di dispositivi elettrocromici (E.C.) costituiti da una struttura a multistrato in cui sono presenti un film
di materiale elettrocromico che costituisce l’elettrodo otticamente attivo, un elettrolita
polimerico ad alta conducibilità ionica ed un controelettrodo costituito da un altro materiale E.C. complementare o da uno strato di materiale conduttore e trasparente. Tali
dispositivi commutano da uno stato trasparente ad uno colorato per applicazione di un
potenziale di basso valore (circa 3 V) e piú specificatamente a causa del meccanismo di
inserzione/rimozione di ioni nel materiale elettrocromico. Fra gli ossidi dei metalli di transizione che esibiscono il fenomeno del l’elettrocromismo, in particolare vengono utilizzati
30
l’ossido di Nichel (NiO) e l’ossido di Tungsteno (WO3). Il polimero utilizzato è ottenuto
dall’ossido di polietilene (PEO) a cui sono aggiunti sali metallici e la cui conducibilità è incrementata con la formazione di opportuni copolimeri. I dispositivi elettrocromici trovano
applicazione nell’edilizia, nell’industria automobilistica e per la costruzione di sistemi per
comunicazione a visore. Il gruppo opera anche nell’ambito del Progetto Sud dell’Istituto
Nazionale di Fisica della Materia, cofinanziato dalla Comunità Europea, fondo europeo
di sviluppo regionale.
10.3
LANDIS: Laboratory of Non Destructive Analysis
G. Pappalardo, G. Calvi, A. Di Pietro, A. Musumarra
It is well established that the modern tendency of the archaeometric approach to the
study of ancient artifacts is to produce new instruments and methods to obtain as much
information as possible on the object without destroying any (even small) part of it and
avoiding to move it from its natural place of custody.
A collaboration has been established with the Laboratorio Nazionale del Sud INFN,
Catania, aimed to develop instruments and methods for non destructive (nd) and in situ
analysis of ancient artifacts of human cultural heritage.
The research program concerns:
DEVELOPMENT OF PORTABLE XRF SYSTEMS that make use of radioactive
sources and X-ray tubes. The aim is to obtain nd information on the constituents of
building stones of monuments with particular care to the detection of heavy trace-element
of petrological interest.
The present main applications concern:
- Provenance study of the mediterranean obsidian by means of nd determination of the
Rb , Sr,Y, Zr and Nb content.
- Characterization of carbonic rocks quarries located in the South of Sicily through the
nd measurements of the Ca and Sr content.
- Non destructive determination of heavy elements of petrological interest in greek pottery
and sample grouping using the multivariate cluster analysis based on direct comparison
of X-ray spectra (”fingerprint XRF method”).
DEVELOPMENT OF A PORTABLE PIXE ( Particle Induced X-ray Emission) SYSTEM making use of an alpha 210 P o source to induce X-ray fluorescence. This
system, due to the well localized absorption of alpha particles, is particularly suitable for
in situ nd determination of major elements present in pigments and in very thin (few
micron) surface layers.
A study is also in progress to face the problem of marble characterization by using an
energetic X-ray source to induce fluorescence on heavy trace elements (rare hearts) and
detecting the emitted X-rays by means of large solid angle Ge detectors. Moreover, the
production of a X-rays portable µ-probe is under study.
31
10.4
Physical methodologies applied to the environmental and cultural heritage
S. O. Troja, G. Burrafato, E. Turrisi, A. M. Gueli, A. Cro, C. Caputa, Q. Di
Felice, F. Foti
The line of research is directed at the application of well-established dating methodologies, such as Thermoluminescence, to pottery and clay materials from Sicilian archaeological sites and at the development of new methodologies for the dating and characterization
of archaeological material and of the geological strata in which they are found. The development of optically stimulated luminescence, OSL and of new dating methodologies
associated with this technique is, instead, closely correlated to accurate detection and
analysis of the luminescent response to stimulation in terms of both excitation and emission spectra, together with the temporal evolution of the latter, to the identification of
the relations existing between the combination centres responsible for TL and those for
OSL and of the relation existing between emptying by heating and optical irradiation or
solar exposure. The application of the TL methodologies to the dating program presently
in course (dating of archaeological sites of the prehistoric period in the middle zone of
the Platani valley, of the Punic-Phoenician site on the island of Mozia - above all this
site offers the possibility to interrelate TL and OSL archaeological and geological, dating
in an environment containing OSL datable lacustrine sediments with tests already performed - of architectonic structures of the ”Terme dell’Indirizzo” and of the Benedectine
Monestery, with lava sediments both in blocks and in re-fired bricks) appears a natural
progression in the application of the methodologies.
10.5
DSI and FUZZY Collaborations
S. Panebianco, C. Petta, N. Randazzo, S. Reito, G. V. Russo, M. Russo
The Catania group is involved in R&D about a large area planar SDD (Silicon Drift
Detectors). As well known, SDDs are position sensitive detectors based on the measurement of the transport time of charge deposited by a particle passage; so, every time
the event rates are not too high, their use is competitive for the good resolution and
multitrack capability achievable. Therefore they are suitable for use in astrophysics experiments, in radiodiagnostics apparatus, in heavy ion and particle physics experiments.
Actually, several designs for prototypal chambers are available for testing and technological improvements.
Two are the main aims we point at. The first one concerns the characterization of
the detector, carried out through checking of linearity for the integrated voltage dividers
and measuring drift time and charge collection. We have tested an experimental setup
with a pulsed light generator (lambda=890 nm) in optical fiber coupling (20 micron)
and we are going to use it as a charge injector on the detector. The SDD and its readout
electronics are put on a board positioned on a x-y micrometric table, to explore sensitivity
and position resolution. The experimental setup should be put inside a clean room to
accomplish safe testing and characterizations.
The second our goal is to propose and realize a readout system for SDDs. We studied
and proposed [3] a solution involving fuzzy logic to carry out on-line data reduction.
A fuzzy signal processor is foreseen to decode the useful information (tracking particle
32
position) with resolution better than 20 microns in both spatial SDD dimensions. Readout
performances are actually object of massive simulations.
An ASIC preamplifier and an ASIC WTA were designed and projects are going to
be sent to the foundry. They constitute some of the most relevant blocks of the entire
readout system. Two researchers, two PHD students and several other students are
actually involved in this program of Analog VLSI ASICS Full Custom.
10.6
GeSi materials and devices
S. U. Campisano, G. Franzó, F. Priolo, E. Rimini
Si/GeSi heterostructure devices may play an important role in microelectronics since
the Si/GeSi heterojunction fabrication technology has shown noticeable improvements.
Unfortunately, difficulties with the incorporation of CVD or MBE based GeSi growth
techniques into the current very large scale integration (VLSI) technology are delaying the
commercialization of the GeSi devices. An alternative approach for fabricating Si/GeSi
heterojunctions may be a technique based on high dose Ge ion implantation into Si,
since ion implantation is a well established VLSI technique characterized by a high wafer
throughput. One of the activities of the laboratory has been then directed toward the
formation of epitaxial Si/GeSi heterojunctions by high dose Ge ion implantation in Si
followed by solid phase epitaxy. This technique was adopted for fabricating Si/GeSi
heterojunction n-p-n bipolar transistors (HBT). We used a standard self-aligned, double
polycrystalline silicon process for Si with the addition of the high dose Ge implantation.
The transistors are characterized by a 60 nm wide neutral base with a Ge concentration
peak of 8 at.large density of extrinsic dislocation loops due to the end-of-range damage
of Ge. However, even if the defects are located in the base-collector depletion layer, a
very limited worsening of the base-collector diode characteristics is demonstrated. On
the contrary, for the first time in transistors fabricated by this technique, good electrical
characteristics are observed. Compared to Si homojunction transistors with similar values
of current gain and Early voltage, the HBTs show base resistance and base transit-times
more than two times lower. In addition, in a long term view, noticeable improvements in
Si microelectronics may derive by the use of Si-Ge-C-Pb quaternary alloys. In this field,
we have investigated electrical and structural characteristics of C implanted Si and of C coimplanted GeSi epitaxial layers formed by high dose Ge implantation in (100) Si followed
by solid phase epitaxy. We have showed that in C implanted Si good structural and
electrical characteristics are observed after high temperature annealing. In the GeSi case,
the C co- implantation improves the crystalline quality since the formation of defects at the
Ge end of range is suppressed and the strain is reduced. Moreover, we have demonstrated
that also suitable Ti silicidation processes have the capability to completely suppress the
formation of secondary defects. In the near future, then, we intend to explore the potential
of these new technologies in experimental electronic devices.
10.7
Helium Implantation: voids, gettering and oxide formation
S. U. Campisano, G. Franzó, F. Priolo, E. Rimini
33
Voids can be formed in silicon by light ion implantation and annealing. Helium
presents many advantages with respect to other light ions: due to its high permeability evaporates easily from silicon surface while, being an inert gas, does not interact with
silicon or other specie, so that no impurity is left in the silicon wafer. The density, morphology and distribution of voids have been studied as a function of the helium implanted
energy (20-300 keV) and dose (1× 1016 - 5 × 1017 /cm2 ) and the annealing temperature
(800 - 1200 C), demonstrating the possibility to form a narrow void layer at a depth
controlled by the implantation energy and with void dimensions and density determined
by the annealing temperature. Voids results stable even at high temperature (1250 C)
for long thermal processes (up to 5 hours). The unsaturated Si bonds present on the
void surface can getter metal impurities. The application of voids as gettering centers
has been investigated considering several devices (large and small area diodes and transistors). Processing temperatures higher than 1000 C causes the release of trapped atoms
but do not affect the gettering efficiency of voids (as a difference with other gettering
centers) so that a new segregation annealing allows to re-localize the metal impurities in
the void layer. Studying the gettering and the release of Pt atoms we determined the
binding energy (1.5-2 eV) while other gettering properties (peak and total concentration)
were related to the void characteristics. The knowledge acquired demonstrates that voids
can be successfully used as gettering centers in both conventional and proximity gettering
procedures. The presence of levels, associated with voids, near the middle of the band gap
was studied by deep level transient spectroscopy. The energy of these levels was found
to be Ec-Et=0.55 eV and Ev+Et=0.45 eV for electrons and holes, respectively. They
resulted independent on void density, morphology and distribution. We suggested a novel
application of voids in silicon, i.e. the possibility to control locally the lifetime in silicon
devices. Applications concern the reduction of parasitic transistor gain in VLSI and circuits and lifetime engineering in IGBT. High dose helium implantation ( 1017 /cm2 ) forms
bubbles which evolve by thermal processes in a continuos buried void layer; it can be used
to obtain a buried oxide layer, i.e. a SOI (silicon on insulator) structure. In this novel
method the void layer is oxidized in dry O2 while oxygen flows in the network through
trenches etched deeper than the void layer. By this method defect free silicon single
crystal layers was obtained. The criteria to produce a void network have been discussed
considering the helium implanted ion dose, energy and the subsequent thermal processes.
Oxidation in dry O2 at different temperatures and for several times has been investigated
and transmission electron microscopy on cross sectional samples has been used to characterize the quality of the buried oxide layers. Applications concerning SMART power
devices and high speed electronics have been investigated.
34
Chapter 11
AREA B: EXPERIMENTAL
NUCLEAR AND PARTICLE
PHYSICS
11.1
CMS Collaboration
S. Albergo, V. Bellini, D. Boemi, Z. Caccia, S. Costa, M. D’Andrea, R.
Potenza, V. Russo, A. Tricomi
The CMS detector has been designed to detect clearly the signatures from new physical
phenomena in p-p reactions at LHC. This will be achieved by precisely measuring the
kinematical characteristics of identified muons, electrons and photons over a large energy
range and at high luminosity. Particular attention will be devoted to the search of the
Higgs boson and to the physics of heavy flavours.
The CMS group of Catania is involved in radiation damage studies of silicon pixels and
microstrips for the internal tracker and in the costruction of a prototype of microstrip
detectors in collaboration with the Department of Physics and INFN of Bari. The Catania
group, together with the Bari group, is involved in the realization of a Regional Center
for silicon microstrip production.
It has been proposed to do radiation damage measurements in the LNS structure and
Some measurements have been done to evaluate the dose by measuring the activation of
an aluminium foil, and to study the induced damage on a few diodes with or without the
relative front-end electronics. I-V and C-V characteristics have been measured for these
diodes. The Catania group has also been actively involved in the compilation of the CMS
computing and software technical proposal.
11.2
Study of the giant dipole resonance in very ho
nuclei
E. Migneco, C. Agodi, R. Alba, G. Bellia, R. Coniglione, A. Del Zoppo,
P. Finocchiaro, C. Maiolino, P. Piattelli, D. Santonocito, P. Sapienza
Lo studio delle reazioni nucleari fra ioni pesanti alle energie intermedie é particolarmente importante perché consente di studiare la materia nucleare in stati altamente
35
eccitati, il suo limite di stabilitá, i modi di decadimento e in generale la dinamica della
formazione dei nuclei caldi. L’evoluzione della Risonanza Gigante di Dipolo (GDR), in
funzione dell’energia di eccitazione, puó fornire informazioni sui limiti di esistenza dei
moti collettivi in sistemi nucleari ad alta temperatura.
Con l’apparato MEDEA, implementato da con una camera a ionizzazione del tipo
“Parallel Plate Avalanche Counter” (PPAC), sono stati studiati nuclei caldi di massa
∼110 formati con il meccanismo della fusione incompleta nella reazione Ar + Zr a 27
MeV/A e Ar + Mo a 37 MeV/A attraverso la misura simultanea dei γ di diseccitazione
della GDR, delle particelle cariche leggere e dei residui di evaporazione.
Per nuclei di massa A ≈ 110 esiste un’ampia sistematica di dati fino ad energie di
eccitazione di ∼300 MeV . Sopra i 300 MeV di energia di eccitazione la saturazione
osservata nella molteplicitá di γ ha dato origine a delle interpretazioni divergenti. Per risolvere queste controversie si é cercato di studiare l’evoluzione della molteplicitá γ e della
larghezza della GDR in funzione dell’energia di eccitazione, fra 350 e 550 MeV, determinando contemporaneamente l’energia di eccitazione e la temperatura del nucleo caldo
formatosi attraverso la misura della velocitá del residuo di evaporazione (misurata nei
PPAC), degli spettri in energia di LCP e della loro molteplicitá (misurati con MEDEA).
Uno dei risultati piú rimarchevoli di questo studio é l’evidenza di una saturazione della
γ-yield osservata sopra i 300 MeV di energia di eccitazione per le due reazioni studiate.
La saturazione non puó essere spiegata assumendo un aumento della larghezza della GDR
ad alte energie di eccitazione ma é necessario prendere in considerazione una soppressione
dell’emissione γ sopra i 250 MeV di energia di eccitazione. Una possibile spiegazione di
questa soppressione potrebbe essere la competizione fra diversi meccanismi. Il nucleo puó
raffreddarsi mediante l’emissione di frammenti e particelle e/o mediante il decadimento di
γ di GDR. Infatti se il tempo di emissione di particelle e frammenti é piú breve del tempo
di vibrazione caratteristico della GDR, l’emissione di γ della GDR avverrá solo dopo che
il nucleo si é giá raffreddato emettendo particelle e frammenti. Un nuovo esperimento, da
effettuarsi presso il Laboratorio Nazionale del Sud, é stato proposto allo scopo di verificare
quest’ultima ipotesi. L’apparato MEDEA + MULTICS consente infatti di selezionare in
modo preciso il canale di uscita della reazione e di misurare contemporaneamente temperatura ed energia di eccitazione del nucleo residuo.
11.3
Study of the production mechanism of hard photons and energetic protons
E. Migneco, C. Agodi, R. Alba, G. Bellia, R. Coniglione, A. Del Zoppo,
P. Finocchiaro, K. Loukachine, C. Maiolino, P. Piattelli, D. Santonocito,
P. Sapienza
Alle energie incidenti vicine all’energia di Fermi l’emissione di pre-equilibrio diventa
sempre piú importante e puó influenzare l’evoluzione della dinamica nucleare verso l’equilibrio.
Uno dei problemi odierni é avere delle informazioni sulle proprietá della materia nucleare
in questa prima fase non equilibrata della reazione in cui si raggiungono le densitá e le
temperature piú elevate. Delle buone sonde per investigare questi aspetti sono i γ e i
protoni di alta energia. Il meccanismo di produzione di γ di alta energia é giá stato investigato mediante misure inclusive e mediante poche misure esclusive che indicano che i γ
sono prodotti come emissione di bremssstrahlung in collisioni n-p. Molti approcci teorici
sono stati tentati anche per spiegare la natura dei protoni di pre-equilibrio (Ep ≥40 MeV).
36
Una serie di esperimenti esclusivi, volti alla misura di γ e protoni di alta energia, é
stata giá effettuata a GANIL con l’apparato MEDEA. Reazioni, con fasci di Ar e Xe
all’energia incidente di 44 MeV/A, sono state effettuate su vari bersagli. In particolare
é stata effettuata una caratterizzazione del meccanismo di produzione in funzione del
parametro d’impatto della reazione che indica come i γ di alta energia e i protoni di preequilibrio provengano da urti n-p nella zona di collisione. noltre lo studio della funzione
di correlazione γ-p conferma in modo inequivocabile l’ipotesi che almeno i protoni e i γ
piú energetici sono originati dalle prime collisioni n-p e quindi durante i primi istanti della
collisione.
Negli spettri con alta statistica si é messo in evidenza l’esistenza di protoni di energia
molto alta ben oltre il valore del limite cinematico. L’esistenza di protoni cosı́ energetici
puó essere dovuta alla presenza di code di alto momento nella funzione d’onda nucleare che
per effetti dinamici e quantistici possono essere presenti nei primi istanti della collisione.
Alla luce di questi ultimi risultati sembra interessante estendere la funzione di correlazione
giá studiata a valori ancora piú elevati di energia di protoni e γ allo scopo di studiare piú
in dettaglio l’origine dei protoni di cosı́ alta energia. Lo studio di tali fenomeni é lo scopo
di una serie di esperimenti esclusivi da effettuare presso il LNS con l’apparato MEDEA
+ MULTICS.
Recentemente é stata riportata l’osservazione che una frazione dei γ con energia fra
30 e 50 MeV sono provenienti non dalle prime collisioni n-p ma da collisioni di ordine
successivo in uno stadio piú tardo della reazione quando un certo grado di termalizzazione
é raggiunto (per questo motivo sono chiamati γ ”termici”). Per capire la natura di γ
con energia ≥30MeV dei calcoli BUU sono stati fatti. Questi ipotizzano il seguente
scenario. All’inizio della reazione un sistema denso é formato nella zona di collisione e i
γ piú energetici, quelli dovuti alle prime collisioni, sono emessi. Poi il sistema si espande
fino a quando la parte attrattiva delle forze nucleari non lo ricomprimono. In questa
fase i γ ”termici” vengono emessi. Ma secondo il modello di espansione-evaporazione la
multiframmentazione ha luogo proprio durante la fase di espansione. Se queste ipotesi
sono corrette si dovrebbe allora osservare un’anticorrelazione fra γ termici e frammenti.
L’apparato MEDEA + MULTICS é altamente performante per questo tipo di misure. Un
esperimento a riguardo é giá stato effettuato presso il LNS con i primi fasci del Ciclotrone
Superconduttore ed i dati sono ancora nella fase preliminare di analisi.
11.4
Fusion and Binary-decay mechanism in the 35Cl+24Mg
system at E/A ≈ 8 MeV/nucleon
Salvatore Cavallaro, E. De Filippo, G. Lanzanó, A. Pagano e M.L. Sperduto
La competizione tra il processo di fusione e i processi binari e’ stata studiata per il
sistema 35 Cl+24 Mg all’energia del fascio incidente di 282 MeV. Sono state ottenute le
distribuzioni angolari e gli spettri energetici relativi ad ogni frammento identificato in
carica. Quindi, integrando i vari contributi ai vari angoli, sono state ricavate le sezioni
d’urto per i processi di fusione completa e di fusione incompleta, come pure quelle relative
ai processi binari. In questi ultimi eventi si nota un contributo che evolve dal processo
quasi-elastico ai processi completamente rilassati in energia, man mano che le cariche dei
due frammenti binari hanno valori piu’ differenti da quelli del proiettile e del bersaglio.
Le componenti parzialmente rilassate presentano distribuzioni angolari caratteristiche dei
37
frammenti quasi-proiettile e quasi-bersaglio. Le componenti completamente rilassate invece, presentano tempi di decadimento che sono confrontabili o piu’ grandi del tempo
di rotazione del sistema di-nucleare. Queste componenti mostrano distribuzioni angolari dσ/dΘ praticamente costanti con l’angolo ed, essendo ben riprodotti ia come energie
cinetiche medie che come distribuzioni in Z, dal modello ’transitional State’, vengono
attribuite al processo di fusione-Fissione.
11.5
Statistical binary decay of
MeV/nucleon
35
Cl +24 M g at ≈8
Salvatore Cavallaro, E. De Filippo, G. Lanzanó, A. Pagano e M.L. Sperduto
Il decadimento in due o piu’ corpi, della reazione 35 Cl +24 M g, e’ stato studiato mediante misure delle coincidenze frammento-frammento, all’energia del fascio incidente di
275 MeV . L’analisi in termini di distribuzione della carica mancante ha mostrato che
la maggior parte degli eventi sono di tipo binario e che il contributo del break-up in tre
corpi e’, nei limiti della sensibilita’ dell’apparato sperimentale, trascurabile. Gli eventi di
tipo completamente rilassato sono dovuti al fenomeno di fusione-fissione e possono essere
riprodotti dal modello ’Transition State’. Tuttavia, in questo lavoro, viene mostrato come
la distribuzione degli eventi possa venir anche riprodotta anche dal modello statistico ’Extended Hauser-Feshbach’
11.6
Fission Decay of
48
Cr at E∗CN ≈60 MeV
Salvatore Cavallaro
Sono state investigate le strutture osservate negli spettri di energia di eccitazione dei
frammenti nei canali di uscita, relative alle reazioni 36 Ar+12 C, 20 Ne+28 Si e 24 M g+24 M g,
che portano allo stesso nucleo composto 48 Cr in condizioni di stessa energia di eccitazione.
In reazioni, dove tipicamente si sono osservate risonanze molecolari, dal confronto dei dati
relativi alle coincidenza gamma di diseccitazione - frammenti, con il modello statistico,
e’ stato possibile spiegare per la prima volta in questa regione di massa, l’origine della
competizione tra i fenomeni di risonanza ed il processo di fissione.
11.7
Heavy-ion reactions at Tandem energy
S. Aiello, N.Arena, Seb.Cavallaro, S.Femino’, G.Lanzalone, S.Pirrone, G.Politi,
F.Porto, S.Romano, S.Sambataro
Nel 96 e’ stato completato lo studio della reazione 35 Cl +12 C alle energie incidenti
E(35 Cl)= 70, 90, 110,125, 140 e 154 MeV. Scopo di tale studio e’ stato quello di misurare
la sezione d’urto di fusione completa e di verificare se in questa regione di energia fosse
presente una componente di fusione incompleta. Dall’analisi degli spettri di velocita’,
costruiti per ogni residuo di evaporazione, e’ stato possibile dedurre che il principale
contributo alla sezione d’urto di reazione proviene dalla completa fusione, ma che processi
di incompleta fusione sono presenti anche a queste basse energie, nell’ordine del 3-6 %
38
della sezione d’urto di fusione completa. Inoltre una analisi cinematica e dinamica dei
contributi di incompleta fusione ha permesso di attribuire l’incompleta fusione ad un
processo diretto di trasferimento di massa, tipo ”massive- transfer”. Tali misure hanno
ulteriormente confermato le previsioni di Morgenstern et al. sulla dipendenza della sezione
d’urto di incompleta fusione dall’asimmetria del sistema e dalla velocita’ del partner
leggero della reazione.Il confronto tra i dati sperimentali e i modelli teorici ha mostrato
complessivamente un buon accordo.
Inoltre e’ stato completato lo studio della reazione 19 F +56 F e all’energia incidente
19
E( F )= 123 MeV. In particolare sono stati misurati gli spettri di energia e le distribuzioni
angolari in massa e carica degli eiettili che vanno dal 11 B al 22 N e. Si e’ trovata una coesistenza dei processi di ”deep inelastic” e di incompleta fusione. Il confronto dei dati
sperimentali con le previsioni teoriche ha messo in evidenza la possibilita’ di trattare i
contributi di ”deep inelastic” nell’ambito del modello ”Sum Rule” di Wilczynski, analogamente ai contributi di incompleta fusione.
Tutte le misure suddette sono state effettuate presso il Laboratorio Nazionale del Sud
di Catania, utilizzando i fasci accelerati dal TANDEM SPM13.
11.8
Fission of targetlike nuclei produced by bombarding haevy nuclei with light projectile at the
tandem energy
S.Aiello, M. Blancato, A. Conti, E. De Filippo, M. Geraci, E. Geraci, G.
Lanzalone, G. Lanzanó, S. Lo Nigro, C. Milone, A. Pagano, S.Pirrone, G.
Politi, F.Porto, S. Sambataro
Peripheral fission reactions induced by the bombardment of heavy nuclei with light ions
at incident CM energy near the coulomb barrier of the two interacting ions are dominated
by a massive transfer mechanism from the projectile to the target nucleus leading to the
formation of excited targetlike nuclei which decay predominantly by a binary fission mode
[1].
The nuclear reactions 16 O +238 U and 19 F +238 U have been investigated at the LNS
Tandem in Catania by looking at the projectilelike fragments (PLF) detected both in
single and in coincidence with the fission (FF) targetlike fragments [2,3,4]. For the first
time, a dominant sequential fission decay has been clearly indicated suggesting that fission induced by direct processes is a slow process. The analytical formulation of the
sequential fission, as given for example in Ref. [5], was adopted in order to extract from
the experimental data the relevant parameters determining the binary scission of the target nucleus, i.e.,: the mean value of the spin J, its degree of alignment on the reaction
plane and the variance K0 of the projection of J on the symmetry axis of fission. The
in plane distribution shows clear fluctuations of the experimental multiplicity to respect
to an average behaviour indicating the presence of strong misalignement of the spin of
the fissioning nucleus. The out of plane distribution shows that the fission fragments are
predominantly emitted in the reaction plane (90◦ ) indicating the population of nuclear
states with large amount of the spin up to a value of J=17h̄.
References
[1] V. E. Viola et al. Phys. Rev. C 26, 178 (1982)
[2] A. Pagano et al. Phys. Rev. C 47, 1170 (1993)
39
[3] A. Pagano et al. Phys. Rev. C 50, 891 (1994)
[4] S.Aiello et al. SIF (1996) and PRC (1997) in preparation
[5] P. Dyer et al. Nucl. Phys. A 322, 205 (1979)
11.9
Deformed configurations in
tion energy
24
M g at high excita-
M. Aliotta, E. Costanzo, M. Lattuada, S. Romano, A. Tumino, D. Vinciguerra
The excitation functions of the 12 C +12 C →8 Begs +16 O and 12 C +12 C → α +20 N e reactions have been studied in the range of c.m. energies from 20 to 36 MeV. The resonance
+
12
at 32.5 MeV previously observed by other authors in the 12 C(0+
2 ) + C(02 ) channel has
been seen to decay also into the less deformed 16 Ogs +8 Begs system. The main features of
the angular distributions are also similar in both exit channels and can be described only
assuming that many partial waves contribute to the resonance. These results suggests
that 24 M g states belonging to different rotational bands, related to different alpha configurations, overlap in this energy region. The hypothesis of rearrangement mechanism of
the alpha clusters in the excited 24 M g can give a qualitative description of the different
modes of decay of this resonance.
Other resonances about 1 MeV wide are also present in this channel at lower energies
down to 20 MeV but they cannot be explained by the excitation of states belonging
to a simple rotational band and need further investigation. A statistical analysis is in
progress, in order to find possible correlations between these resonances and the ones
observed, during the same experiments, in the outgoing channel producing a residual 16 O
excited at its first levels.
11.10
Isospin role on nuclear structure and on nuclear collision properties
F. Amorini, M. Cabibbo, G. Cardella, A. Di Pietro, P. Figuera, A. Musumarra,
M. Papa, G. Pappalardo, F. Rizzo, S. Tudisco
In the last few years an accurate analysis of the isospin role on nuclear structure and
on nuclear collision properties has been favorite by the availability of radioactive beams.
For example, the presence of a ”proton halo” can be evidenced measuring the subCoulomb stripping induced by mirror projectiles on target nuclei having closed shells. We
measured the mirror reaction:
40
Ca(13 C,12 C)41 Ca and 40 Ca(13 N,12 C)41 Sc
at Einc = 20M eV at the Cyclotron Laboratory of the Catholic University of Louvain,
Louvain-la-Neuve (Belgium).
The charged particles were detected at backward angles by an annular silicon detector.
By using the T.O.F. technique it was possible to separate light particles (proton,alpha)
from heavy ones (Nitrogen, Carbon). Due to the low outgoing energy of heavy fragments
the charge identification through the traditional ∆E-E technique was not possible as the
commercial ∆E detectors have a minimum available thickness of ∼ 5 µm. We tried to
identified the heavy fragments on the basis of the kinematics but the energy separation
40
between 13 N and 12 C was not enough respect to the energy spreading to discriminate the
two different contributions.
This results challenged the development, in collaboration with the SGS Thomson, of a
monolithic silicon detector telescope having an ultrathin ∆E stage (1µm) followed by an
E detector 400µm thick. The performances of this telescope have been successfully tested
at the Laboratorio Nazionale del Sud (Catania) using low energy 12 C, 14 N , 28 Si and 58 N i
beams on different targets. The energy threshold we obtained is 300-400 keV/A in the
Nitrogen zone, low enough for the experiments planned in 1996.
The role of the isospin purity and/or mixing in the statistical processes can be investigate measuring the γ-decay from GDR built on excited states of self-conjugate nuclei. In
fact the selection rules for the E1 transition require a ∆T=1 isospin variation then, if the
isospin is conserved in the heavy ion fusion reactions, the GDR γ-decay from a compound
nucleus formed with T=0 entrance channels should be inhibited respect to T=1 ones, due
to the low T=1 density levels at low excitation energy.
The compound nucleus population by means of different isospin entrance channels is
now possible using stable and radioactive beam.
Up to now the following reactions have been studied:
13
N +11 B → 24 M g T=0,1 (Louvain-la-Neuve LLN, Belgium)
14
N +10 B → 24 M g T=0 (LNS, Italy)
at E ? =48 MeV.
We measured the γ-rays in coincidences with charged particles using, in LNS experiment,
the TRASMA experimental set-up placed at the 20◦ line. It consists of 63 BaF2 detectors
for γ-rays and a two stage telescope ∆E-silicon strip detector and E-CsI(Tl) crystals for
the charged particle detection.
A slightly modified set-up was used at LLN experiments where the LEDA silicon strip
detector, combined with RF signal from the cyclotron, furnishes mass identification.
A strong isospin effect is observed in 13 N +11 B → 24 M g T=0,1 collision where
the T=1 component appears to be quenched. This results could be due to a hindrance
of C.N. formation, structure of the C.N. or competition with other decay channels like
fission.
Always in collaboration with the Louvain-la-Neuve group, we started the study of 32 S
through the 19 N e +13 C collision. The 32 S nuclei were populated by T=0,1 channels at
E ? =49 MeV (Einc =44 MeV).
To complete the study we planned to measure in 1996 the following reactions:
12
C +20 N e T = 0 Einc = 50M eV
16
O +16 O T = 0 Einc = 67M eV
for which a simple gas-target device has been developed.
11.11
A new monolithic silicon detector telescope
F.Amorini, M.Cabibbo, G.Cardella, A.Di Pietro, G.Fallica, P.Figuera,
G.Franzó, A.Musumarra, M.Papa, G.Pappalardo, G.Percolla, F.Priolo,
V.Privitera, F.Rizzo, S.Tudisco
The study of nuclear reactions using both stable and radioactive beams usually requires
the detection and the identification of the emitted fragments.
The charge identification can be achieved by means of the ∆E-E technique measuring the
energy loss in the first stage of a detector telescope. To detect low energy light fragments
41
a gas ionization chamber is often used as first ∆E stage. Nevertheless in some cases
experimental constraints require more compact detection systems like silicon detectors.
Since very thin ∆E detectors are not feasible due to fragility problems, we decided to
develop, in a collaboration between nuclear and solid state physicists, a new monolithic
silicon telescope. The two stages ∆E-E are obtained by means of high energy Boron P+
implantation (Einc = 900keV ) on an high resistivity N-type silicon crystal. The electric
contact between the buried anode (at about 1µm of depth) and the front face of the
telescope was made by low energy implantation followed by high temperature (900◦ C)
diffusion. The effectiveness of the design allows both an easy housing of the detector and
a very low energy identification threshold.
To test the performances of the monolithic telescope several measurements have been
made using the beams delivered by the Tandem Accelerator of Laboratorio Nazionale del
Sud in Catania. Particular care was devoted to calibrate both stages. The analysis of
the experimental results shows that using this new device it is possible to detect and to
charge identify light fragments, like Carbon, Nitrogen, Oxigen, with good resolution down
to 300 keV·A.
11.12
Particle-gamma coincidence measurements: effect of the particle selection on the γ-spectra
F.Amorini, M.Cabibbo, G.Cardella, A.Di Pietro, P.Figuera, A.Musumarra,
M.Papa, G.Pappalardo, F.Rizzo, S.Tudisco
In the last years we studied several reactions at around 5 MeV/A detecting charged
particles in coincidence with gamma rays. In particular we measured the systems
12
C +64 N i at 94 MeV, 14 N +10 B at 48 MeV, 19 F +12 C at 121.7 MeV, 13 N +11 B at 44
MeV. For such experiments we used the TRASMA detection system of the Laboratorio
Nazionale del Sud of Catania (Italy). It consist of 63 BaF2 detectors arranged in 9 clusters
of 7 crystals each to detect gamma rays, and of a forward hodoscope to detect and identify
(in mass and charge) particles emitted from 3◦ to 15◦ . In these measurements we saw a
large effect of the coincidence on the gamma ray spectra. Selecting the fusion reaction
mechanism with different triggers like protons, alphas or evaporation residues at various
detection angles, we obtain strong differences on the gamma ray spectra. Such differences
originate from a selection in spin that one performs imposing the coincidence and it is a
consequence of the different decay probability for the various particles as a function of
the spin of the emitting nucleus.
To better understand the above mentioned trigger effect we developed a MonteCarlo
program based on the well know statistical code CASCADE. This code, coupled to a
kinematical code, is well suited to account for any experimental constraint. Moreover
with such a code we reproduced all the ratios between the gamma ray spectra obtained
in coincidence with the different triggers. Particularly interesting is the reproduction of
the GDR suppression observed in coincidence with high energy alpha particles previously
reported for the 19 F +12 C reaction. This kind of analysis is very important for the
analysis of the GDR gamma decay to disentangle GDR suppression effects due to isospin
conservation rules or other mechanisms from trivial trigger effects.
42
11.13
Preequilibrium gamma ray emission in heavy
ion collisions
F.Amorini, M.Cabibbo, G.Cardella, A.Di Pietro, P.Figuera, A.Musumarra,
M.Papa, G.Pappalardo, F.Rizzo, S.Tudisco
The gamma-particle coincidence measurements offer the possibility to study the behaviour of the gamma emission when a selection on the different reaction mechanisms is
done. This in turn allows to study directly the dynamics of the collision process.
With this respect the study of the experimental data collected on the 12 C +64 N i at 94
MeV and on the 35 Cl +64 N i at 271 MeV collisions, performed by means of semiclassical
kinetic theories and a modified statistical approach, has led to a clear distinction between
a preequilibrium dynamical γ-ray emission as due to the proton-neutron equilibration
motion and a ”preequilibrium statistical” γ-ray emission in which, even if the above
collective motion is equilibrated, the preequilibrium effects are produced by the slow
changing in time of the shape degrees of freedom.
In particular the ”anomalous” character of the high energy γ-ray production evidenced
in these collisions has been interpreted as a dipole emission produced by the strongly
deformed intermediate system formed during the first 200-300 fm/c of the collision process.
The study performed at different impact parameters has put also in evidence the link
between collective transfer of charge and mass in the nuclear reactions and preequilibrium
emission from the intermediate system. With the quantitative analysis done to reproduce
the experimental data and the above mentioned comparison with the statistical model,
we have evidenced the key role played by the reaction mechanisms (fusion, deep-inelastic
and massive transfer reactions) on the visibility of the preequilibrium effects. To this
aim also the possibility to reproduce initial clustered structures in nuclei by means of the
semiclassical mean-field theory and the relative influence on the reaction mechanism has
been discussed.
Finally the dynamical study of the proton-neutron motion equilibration phenomenon
has put in evidence also the existence of a preequilibrium Isovectorial Quadrupolar strength
which could be very promising for a better and further understanding of the Compound
Nucleus formation process.
11.14
Particle-gamma coincidence measurements for
the study of the GDR gamma-decay; results
from the TRASMA apparatus at Tandem and
cyclotron energies
We have analyzed the data obtained with the reaction 12 C +64 N i at 94.6 MeV measured at
the LNS of Catania with the TRASMA detection system consisting of 63 BaF2 crystals for
gamma-rays detection and of an 8 sector modular telescope for forward emitted charged
particles detection and identification. The flexibility of the forward particle detector
allowed the use of three different triggers for gamma detection. In such a way we obtained
gamma ray spectra gated with heavy residua coming from fusion reactions, alfa particles
produced in fusion and incomplete fusion reactions and 8 Be coming from incomplete
fusion of the projectile.
43
In coincidence with heavy residua we observe the GDR gamma decay of the resonance
built on excited states of the compound nucleus 76 Se. The position of the GDR is in
agreement with the systematic. The observed width is about 15 MeV. This is to big
compared with systematic in the region of 120 Sn but similar to what observed for 63 Cu.
In coincidence with alpha particles a GDR gamma ray decay suppression is observed.
This is due to different combined effects. Firstly in the C.N. decay high energy gamma
rays are emitted in competition with alfa’s, as can be shown by looking to the results
of a MonteCarlo version of the statistical Cascade code that we have developed. The
second and most important reason is the dominance of the incomplete fusion reaction
mechanism as production mechanism for the detected alpha particles. If the detected
alpha come from the break-up of the 12 C, only an incomplete momentum transfer occurs
and the excitation energy of the system is lower than for complete fusion. This gives a
lower probability for GDR gamma decay.
Similar considerations can be performed in the case of 8 Be trigger. γ-spectra have
not enough statistic to show GDR but their slope is consistent with the slope observed in
coincidence with alpha particles.
A small discrepancy between experiment and statistical calculations is observed around
14 MeV in the gamma-heavy residua coincidence spectrum. This could be due to some
preequilibrium gamma ray emission from the dinuclear system formed in the first stage
of the reaction. To better understand this discrepancy we performed also semiclassical
calculations. A code has been developed in which the Vlasov equation is solved by means
the Test-Particles method using a mean field obtained through two-body Skirme forces.
The preequilibrium GDR emission for the system 12 C +64 N i, 35 Cl +40 Ca, 40 Ca + 40 Ca at
around 8 MeV/A has been studied. In particular we have developed a new way to compute
the rate of preequilibrium emission through the estimations of the relative E.W.S.R.
The resulting yields can be compared easily with the statistical emission. The emission
probability computed for each collision has shown a marked increasing behaviour with
the charge asymmetry differences of the two partners of the collision. The observed rate
can be, in the favourable cases, a factor 2-3, with respect to the statistical contribution.
These self-consistent semiclassical calculations strongly address to the study of similar
system with large differences in the charge asymmetry to detect clearly the preequilibrium
emission. In this way in fact the statistical emission should be practically the same and
the dynamical effects due the initial channel could be evidenced from the comparison of
experimental results in an independent way from the statistical emission. Following these
indications we will start in 1996 further experimental works.
Finally in 1995 the TRASMA detection system was the first apparatus reached by the
58
N i beam at 30 MeV/A delivered by the superconducting cyclotron of the LNS. We used
this beam on an 27 Al target measuring in coincidence charged particles detected with the
forward particles detector system of the apparatus and gamma-rays detected with the
above mentioned 63 BaF2 detectors. The first analysis of collected data was performed
on the coincidences between identified charged fragments between Z=4 and Z=15, and
gamma-rays. The particle spectra show a typical two ridge behavior due to the inverse
kinematic. They seem to be produced in asymmetric fission of the intermediate system.
The gamma-ray spectrum shows a large GDR contribution. The analysis to identify the
source of such GDR emission is in progress.
44
11.15
Elastic scattering and fusion process for the
system p +1 2C
N. Arena, S. Cavallaro, R. Giordano, A. Scalia
Vengono effettuate misure di scattering elastico ad energie sotto la barriera Coulombiana per il sistema p+12C.La sezione d’urto di scattering viene misurata usando un
nuovo apparato sperimentale realizzato nell’ambito dell’esperimento LESCAT finanziato
dall’INFN. Queste misure sono mancanti in letteratura e sono importanti per lo studio dello ”screening” elettronico presente sia nella fusione nucleare sia nello scattering
elastico.La determinazione del peso che lo ”screening” ha nell’innalzamento del fattore
astrofisico nucleare puo’ avere effetti nel calcolo del ”reaction rate” nella nucleosintesi
stellare.
11.16
The short-lived 8Be level at Ex=11.4 MeV
N. Arena, S. Cavallaro et al.
Measurements of the differential cross section for the 7 Li(d, ααn) reaction have been
performed at incident deuteron energy Ed = 19.7 MeV. An appropriate kinematical configuration was chosen to observe the population of the second excited 8 Be level. The
values of (11.3 ± 0.2) MeV for the excitation energy and of (3.7 ± 0.2) MeV for the width
of the above level were found. In determinating the two above spectroscopic parameters
the influence of the transformation Jacobian was taken in account.
11.17
Photonuclear reactions with tagged and polarized gamma beam
V. Bellini, S. Lo Nigro, F. Palazzolo, R. Potenza, V. Russo, A. Sciré, M.L.
Sperduto
A group of researchers of the Physics Department in Catania collaborates with other
Italian, French and Russian groups in order to make available a tagged and polarized
gamma beam (GRAAL) at the ESRF accelerator in Grenoble. The first Compton gamma
beam has been extracted in September 1995 with a maximum energy of 1100 MeV. The
actual beam intensity is 3x106 phot/sec: it is possible to get the maximum beam intensity within a few minutes after the laser glow via a remote control system of the involved
optical instruments.
The tagging system has been installed: it consists of ten plastic scintillators, associated electronics to analyse the signals and data acquisition system. The signal rate from
the tagging is used as a reference mark to align the laser beam onto the electron beam.
Moreover a special circuit based on AsGa technology allows us to tune the phase of the
tagging signal coming from the scintillators with the ESRF radiofrequency phase. This
way we got a < 200 ps FWHM uncertainty in the timing of the general trigger used in
experiments, useful also as a start for all time-of-flight measurements. The right setup
of tagging system has been checked by coincidence measurements between itself and the
quantameter ( spaghetti detector). The part of the tagging system consisting of 128 channels of silicon microstrip has been installed together with the associated electronics and
45
it is still under test.
The physics program has been divided in two phases. The first phase includes experiments with unpolarized targets, namely meson photoproduction and pion polarizability.
The second phase involves the use of polarized H-D targets. An important task is the
measurement of the HDG sum rule, and it is strongly supported by the GRAAL Scientific
Advisory Committee.
Exploratory tests have shown the feasibility of experiments involving the detection of
0
π and η mesons by using the GRAAL photon beam impinging onto a carbon target. The
invariant mass of these particles has been correctly retrieved with a good resolution. In
particular the invariant mass of η has been retrieved both via the decay in two γ and the
alternative decay in three π 0 and subsequently in six γ.
The Catania group takes part to prepare the software analysis programs, that are in
an advanced state and to complement the already available apparata with plastic scintillating discs for the sake of detecting neutrons and pions. The test experiments, carried
out by the Catania group, run at the Southern National Laboratory (LNS) in Catania,
with the assistance of the associate collaborator F.S. De Bastiani.
11.18
Experiment E938H at LBNL (TRANSPORT
Collaboration)
S. Albergo, D. Boemi, S. Costa, Z. Caccia, A. Insolia, R. Potenza, G. V.
Russo, C. Tuvè
L’ esperimento, condotto al Bevalac di Berkeley in Aprile 1990 e Aprile 1991, è consistito nella misura delle sezioni d’ urto delle reazioni di frammentazione del proiettile
nelle collisioni di vari ioni pesanti (dal He al Ni) a energie comprese tra 400 e 1900
MeV/nucleone con targhetta di idrogeno liquido. Dal 1991 l’ analisi dei dati è in corso ed
è proseguita anche per tutto il 1996.
Dopo la pubblicazione del primo articolo sulle sezioni d’ urto per variazione di carica
(1994) sono state determinate le sezioni d’ urto elementali. Indi l’ attività di analisi si è
spostata come previsto su quelle isotopiche. Queste verranno pubblicate in una serie di
articoli, ciascuno dedicato a uno o pochi ioni proiettili.
Spettri di neutroni, distribuzioni angolari, di momento trasverso e di rapidità nella
reazione 40 Ca + H misurati con Muffins sono stati presentati all’ inizio dell’ anno alla
Conferenza di Bormio. Tali spettri mostrano che la produzione di neutroni presenta due
componenti: neutroni prodotti con rapidità del fascio e una lunga coda dovuta a neutroni
con rapidità più bassa. Usando una rappresentazione semiclassica, i neutroni con rapidità
più bassa potrebbero essere prodotti localmente lungo il percorso del protone bersaglio nel
ben più grande proiettile. Essi dovrebbero subire una interazione molto più violenta con
il protone bersaglio e, quindi, acquisire un momento trasverso piuttosto grande. Neutroni
intorno alla rapidità del fascio (quindi con momento trasverso piccolo) dovrebbero essere
prodotti nella parte rimanente del proiettile, una regione alquanto più fredda.
Nel corso dell’ anno è cominciata l’ analisi dei dati relativi ai neutroni da altre reazioni.
46
11.19
Experiment E987H at LBNL (EOS Collaboration)
S. Albergo, G. Cinà, S. Costa, Z. Caccia, A. Insolia, R. Potenza, G. V.
Russo, A. Tricomi, C.Tuvè
L’ esperimento, condotto al Bevalac nel 1992, è consistito nello studio delle collisioni
tra vari ioni pesanti (fasci da Ne a Au, targhette da C a U) a energie relativistiche (tra
400 e 2100 MeV/nucleone). L’ analisi dei dati è iniziata nel 1993 e proseguirà ancora per
diversi anni.
Il primo articolo, in cui determinammo i valori degli esponenti critici associati con una
transizione di fase liquido-gas nei nuclei, pubblicato nel 1994, ha avuto grande risonanza
in tutto il mondo, stimolando l’ attuale grande interesse diffuso in tutto il mondo per le
transizioni di fase nella materia nucleare.
Una gran parte del lavoro che attualmente si fa in questo campo un po’ dappertutto
fa uso dell’ ormai famoso metodo del rapporto delle rese dei frammenti per dedurre la
temperatura delle sorgenti nucleari, un metodo che fu sviluppato proprio presso questo
Dipartimento nel 1985 da S.Albergo, S.Costa, E.Costanzo e A.Rubbino. Dopo la pubblicazione, tra 1994 e 1995, di una nutrita schiera di lettere e contributi a conferenze
riguardanti le ”pietre miliari” che l’ esperimento ha stabilito riguardo al ”flow” e alla
transizione di fase liquido-gas nelle collisioni tra ioni pesanti alle energie del Bevalac, l’
attività di analisi ha continuato a produrre ulteriori interessanti risultati, di più ampio
respiro, che hanno visto la luce nel 1996. Tra essi ci limitiamo a mettere in rilievo i
seguenti due più salienti.
1) L’ approfondimento dell’ analisi degli esponenti critici ha ulteriormente confermato
che i dati EOS sono consistenti con una transizione liquido-gas del secondo ordine. Anche
una analisi della distribuzione di massa dei frammenti in termini della ”scaling function”
risulta consistente con tale ipotesi, mentre la forma della famosa curva calorica pubblicata
dal GSI, indicativa di una transizione di fase del primo ordine, non si ritrova nei dati EOS.
2) Siamo arrivati a delineare una descrizione unificata dei tre tipi di ”nuclear flow”
(trasverso, radiale, squeeze-out) osservati nelle collisioni tra ioni relativistici. In tale
descrizione, un solo tipo di espansione collettiva, radiale ma modulata in funzione dell’
angolo rispetto al piano di reazione, e il meccanismo della coalescenza bastano a descrivere
tutte le osservazioni sperimentali sul flusso collettivo.
Abbiamo anche ottenuto, e presentato al Congresso annuale della Società Italiana di
Fisica, i primi risultati sui valori dell’entropia prodotta nella collisione. L’andamento di
tale grandezza al variare dell’energia di eccitazione liberata dall’ urto potrebbe gettare
nuova luce sul fenomeno di transizione di fase liquido-gas recentemente osservato. Questi
studi saranno approfonditi nel 1997.
Dai dati di Muffins abbiamo ottenuto risultati preliminari sulla molteplicità di neutroni
basata sulla distribuzione della ”prima interazione neutronica” tra i dischi del rivelatore.
Direttamente connessa con l’ ambito scientifico della collaborazione EOS è stata inoltre
la conferenza CRIS ’96, svoltasi nei pressi di Catania e organizzata da 4 componenti del
gruppo (S.Albergo, S.Costa, A.Insolia, C.Tuvè). Il consenso sulla alta qualità scientifica
e organizzativa della Conferenza è stato unanime sia a livello internazionale che locale.
Essa viene qui menzionata nell’ ambito dell’ esperimento EOS in quanto la scelta stessa
del tema da parte degli organizzatori, l’ entuasiastica risposta partecipativa da parte di
colleghi da tutto il mondo, la vivacità del dibattito e il livello di interesse durante i lavori
derivano proprio dai risultati raggiunti dall’ esperimento EOS insieme a quelli ottenuti
47
dall’ esperimento Aladin, due collaborazioni che, entrambe, includono ricercatori catanesi,
nonchè anche da altre importanti collaborazioni.
11.20
Experiment E896 at BNL (H0 Collaboration)
S. Albergo, D. Boemi, G. Cinà, S. Costa, Z. Caccia, A. Insolia, R. Potenza,
G. V. Russo, A. Tricomi, C. Tuvè
Questa sigla indica la collaborazione che si propone di provare (o stabilire stringenti
limiti a) l’ esistenza della particella a 6 quark uussdd denominata H0, predetta da Jaffe
in base al MIT bag model, studiando particolari topologie di decadimento tra le tracce
dei prodotti di reazione in collisioni centrali Au + Au a 11.6 GeV/nucleone, la massima
energia per Au all’ AGS di Brookhaven. In tale esperimento, Muffins deve rivelare (parte
dei) neutroni prodotti dal decadimento della ipotetica H0.
Nel 1996 l’ apparato sperimentale (comprendente 2 magneti, una Drift Chamber, una
TOF wall, diversi rivelatori di trigger e lo spettrometro Muffins) è stato costruito, istallato
e collaudato. L’ esperimento ha avuto fascio dal 5 Dicembre 1996 al 31 Gennaio 1997 con
brevi interruzioni e ha preso i suoi primi dati.
La versione modificata di Muffins (vedi Reports degli anni precedenti) è stata assemblata a Catania in Gennaio-Giugno 1996, spedita a Brookhaven in Luglio e istallata
da un gruppo di tecnici catanesi in Settembre. Ottobre e Novembre sono stati dedicati
alla messa a punto dell’ elettronica, allo sviluppo del software di controllo remoto dell’
elettronica, DAQ e monitoraggio online dei dati.
Dopo una lunga fase di messa a punto delle varie parti dell’ apparato, sono stati registrati 25 milioni di eventi di collisione centrale Au + Au. La cosa interessante è che la
prevista topologia del decadimento della H0 è stata osservata ben 5 volte semplicemente
guardando a campione, online, alcune centinaia di eventi durante i run! Pertanto, tale
topologia dovrebbe essere presente nei dati parecchie migliaia di volte. Questo naturalmente non prova ancora che la H0 esiste, ma solo che i dati contengono effettivamente un
sottoinsieme di eventi in cui vale la pena di cercarla. Il prossimo passo adesso sarà appunto
filtrare i dati in modo da estrarne il sottoinsieme interessante. Per questi eventi dovremo
effettuare la ricostruzione software delle tracce dei prodotti di decadimento nella Drift
Chamber, vedere se Muffins ha o no ”visto” un neutrone e se esso appare provenire dal
presunto vertice di decadimento della H0 e infine tentare di ricostruire la massa invariante
della particella madre.
Anche dal punto di vista del contributo di Muffins alla possibile rivelazione dei neutroni
da decadimento della H0, già il monitoraggio online ha dato indicazioni incoraggianti: in
circa il 10% di tutti gli eventi il rivelatore ”vede” neutroni”. Questo conferma sperimentalmente quanto indicato da GEANT e cioè che nonostante l’ enorme fondo di neutroni
dalla collisione primaria Au + Au, la particolare posizione del rivelatore scelta in base
alle simulazioni e la riduzione della superficie dei dischi consente che il rivelatore non sia
completamente accecato dai neutroni del ”fondo” in ogni evento.
Un campione di dati molto più vasto sarà raccolto in un futuro periodo già assegnato
dall’ AGS per l’ inverno 1997-1998.
48
11.21
ALICE Collaboration
S. Albergo, Z. Caccia, C. Caligiore, G. Ciná, S. Costa, A. Insolia, S.
Panebianco, C. Petta, R. Potenza, D. Lo Presti, N. Randazzo, S. Reito, G. V.
Russo, M. Russo, A. Tricomi, C. Tuvè
The Catania Group is involved in R&D about the different options for the TOF system
for the ALICE detector. Particular attention has been devoted to the study of light signals
from plastic scintillators of various shapes and sizes by means of the single-photoelectron
technique. The shapes studied are: extended disc, circular section slat, rectangular section
slat. This study has included an experimental measurement of the light output from a
large scintillator disc.
Two prototypes for the two different geometries proposed for the TOF system have
been realized and studied in Catania: a grid module and a shingle module [1,2,3]. They
have been tested experimentally using cosmic rays as well as a relativistic particle beam.
Our experimental findings have ruled out the grid option. The shingle modules have been
tested using the proton beam at the AGS of BNL (USA). An additional test is planned
at CERN.
We have contributed also to the R&D for the highest priority option for the HMPID:
the RICH detector, in collaboration with the Bari group and CERN [4].
Finally we have performed calculations, using HIJING code and original parton distribution functions. Our calculations show the importance of parton shadowing effects in
ultrarelativistic heavy ion collisions at energies of interest for the experiments planned at
the LHC [5,6].
11.22
Low energy reactions and features of light nuclei
S. Cherubini, M. Lattuada, S. Romano, C. Spitaleri
Contribution to the understanding of the structure of light nuclei can be given by
the study of special nuclear configurations. To this aim, the following studies have been
performed:
a) experimental search for excited states of 4 H in the d +9 Be reaction;
b) interpretation of the features of (8 Li, α) reactions on light nuclei, by the assumption
of preformation of a 4 H cluster in 8 Li;
c) excitation of special states of light nuclei described in terms of α clusters arranged
on linear chains or star configurations.
11.23
The CMS Experiment at CERN’s LHC
L. Lo Monaco, P. Castorina, A. Insolia
The CMS detector is designed to detect the diverse signatures from new physics by
identifying and precisely measuring muons, electrons and photons over a large energy
range and at high luminosity. The most important searches will be those for the Standard
Model Higgs boson, Supersymmetric particles, CP-violation maesurements and possible
signals for QCD deconfinement from heavy ion collisions. Also topics in top- and B-physics
will be studied.
49
Chapter 12
AREA C: THEORETICAL
PHYSICS
12.1
C1: THEORETICAL NUCLEAR PHYSICS
12.1.1
Risonanze giganti
M. Bassi, A.Bonasera, M.Colonna, V.Greco, A.Guarnera, M.Di Toro, V.Kondratiev,
V.Latora, J.Y.Liu, S.Maccarone, A.Smerzi, H.H. Wolter, M.Zielinska-Pfabe’
Grande lavoro e’ stato fatto sugli effetti della temperatura sulla risonanza di dipolo
isovettoriale. Si e’calcolato l’aumento del damping dovuto alle collisioni a due corpi e
la conseguente sparizione di tali risonanze giganti in nuclei altamente eccitati. Effetti
di memoria nell’integrale di collisione sono stati accuratamente valutati per casi fisici
in nuclei finiti. La possibilita’ di una transizione nella natura dei moti collettivi nucleari, da zero- a first-sound, all’aumentare della temperatura, come gia’ osservato in altri
liquidi di Fermi, viene proposta con effetti importanti legati alle correlazioni nucleari
ed alla presenza di un forte Landau-Damping. Questa transizione renderebbe possibile
l’osservazione di risonanze giganti fino alla massima temperatura che un nucleo in equilibrio puo’ sostenere.
Si e’ proposto lo studio di emissioni di dipolo collettive nella dinamica della fusione
allo scopo di individuare particolari canali di ingresso che possano portare alla formazione
di speciali sistemi nucleari (superdeformati e/o superpesanti). Ad energie intermedie e’
stato messo in evidenza un importante effetto dell’asimmetria di carica del canale di
ingresso che potrebbe permettere di acquisire nuove informazioni indipendenti sul comportamento della risonanza di dipolo calda. Tale linea di ricerca appare molto promettente
per l’utilizzazione dei primi fasci radioattivi disponibili presso il LNS
12.1.2
Dinamica delle fluttuazioni e frammentazione nucleare
50
Si e’ affrontato il problema della frammentazione nucleare, che rappresenta una grande
parte della sez. d’urto di reazione ad energie intermedie (50-100 Mev/u). Da un lato si
e’ messo in evidenza l’importanza di un trattamento microscopico della dinamica del
canale di ingresso. Dall’altra si e’ mostrata la necessita’ della introduzione di fluttuazioni
dinamiche che danno luogo a formazione di frammenti in regioni di instabilita’, in parte
legate a proprieta’ dell’equazione di stato della materia nucleare. E’ stato proposto un
nuovo metodo autoconsistente per introdurre fluttuazioni nelle equazioni del trasporto per
la dinamica nucleare, che permette di generalizzare l’approccio di Boltzmann-Langevin
anche a processi dominati dalla dissipazione ad un corpo. I tempi di calcolo aumentano
notevolemnte in quanto si deve partire da una traiettoria media determinata con grande
accuratezza numerica. Si sta lavorando su uno sviluppo di software per supercalcolatori
paralleli.
Sono stati evidenziati diversi meccanismi per la produzione di frammenti in reazioni
dissipative che vanno da effetti dinamici collettivi, con memoria di particolari modi instabili, a fenomeni critici, quali transizioni di fase liquido-gas, fino ad effetti di coalescenza
nello stato finale in processi altamente esplosivi. I vari scenari sembrano essere comandati
dai tempi di interazione. Si intende sviluppare questo progetto sempre a stretto contatto
con gruppi sperimentali anche in connessione a proposte di esperimento con i primi fasci
disponibili al CS.
12.1.3
Fenomeni critici in sistemi finiti
L’equazione di stato della materia nucleare suggerisce la possibilita’ di una transizione
di fase del tipo liquido-gas ad una temperatura di 15-20 MeV ed una densita’ un quinto
circa di quella normale. Comunque non e’ chiaro che una tale transizione si possa osservare
in sistemi formati da 100-400 costituenti come si ha, per esempio nelle collisioni tra due ioni
pesanti. Per evidenziare gli effetti del numero finito di nucleoni e della carica Coulombiana
si e’ studiata la dinamica esatta di un sistema classico. Le interazione tra due particelle
classiche sono state scelte del tipo Yukawiano ed i parametri del potenziale sono stati
aggiustati in modo tale da ottenere una equazione di stato equivalente a quella di materia
nucleare. Seguendo l’espansione di un sistema formato da circa 100 particelle si e’ studiato
sotto quali condizioni il sistema si comporta in modo ”critico” nell’espansione e con quali
segnali chiaramente osservabili.
Si e’ mostrato chiaramente come gli eventi critici possano essere rilevati sperimentalmente mediante lo studio dei momenti fattoriali. Inoltre, in accordo con le leggi di
scala ricavate dall’idrodinamica, si e’ dimostrato che il flusso collettivo va a zero quando
c’e’ una ”transizione di fase”. L’analisi suggerita da questo lavoro e’ stata gia’ applicata
con successo per individuare eventi di frammentazione associati a transizioni di fase in
esperimenti esclusivi al Ciclotrone MSU.
12.1.4
Descrizione semiclassica della fusione sotto barriera e
della fissione.
51
Usando il metodo proposto da Feynmann, si e’ calcolata la collisione tra due nuclei
pesanti ad energie del fascio sotto la barriera Coulombiana. Il metodo consiste nel risolvere
l’equazione di Vlasov durante l’evoluzione sopra la barriera. Al momento in cui i due
nuclei si fermano a causa della repulsione Coulombiana si passa dal tempo reale al tempo
immaginario e si continua a seguire l’evoluzione del sistema sempre risolvendo l’equazione
di Vlasov (ma con ”it”). In questo modo si puo’ calcolare la probabilita’ di fusione
sottosoglia.
Il metodo e’ stato esteso allo studio della fissione spontanea con risultati molto promettenti. L’alta accuratezza numerica richiesta rende necessario il passaggio a supercalcolatori
paralleli.
12.1.5
Chaotic dynamics in nuclear multifragmentation
A. Atalmi, M. Baldo, G. F. Burgio, A.Rapisarda
In the framework of a mean–field approach we have studied the dynamics of fragments
formation inside the spinodal region of nuclear matter. The Vlasov equation was solved
numerically in a 2D lattice and the system was initialized by a small random perturbation
in order to test its response. The performed investigations have confirmed the chaotic
character of the dynamics previously found. In particular by studying a large ensemble
of numerical events we found a very sensitive dependence on the initial conditions, a
positive largest Lyapunov exponent and a large fractal dimension of the most excited
modes. These results are compatible with a fully chaotic scenario and give a strong
theoretical support to the basic assumption of prompt statistical models. At the same
time an event-to-event analysis has revealed clear signatures of critical behavior. The
chaotic dynamics induces in a very natural way large fluctuations typical of second-order
phase transitions. A preliminary calculation of the critical exponents gives values of β/γ
and τ very close to the liquid-gas phase transition and to those found experimentally.
12.1.6
Chaoticity and dissipation of nuclear collective motion
M. Baldo, G. F. Burgio, A. Rapisarda, P. Schuck
We investigated the behavior of a gas of classical particles oving in a two dimensional
”nuclear billiard” whose multipole-deformed walls undergo periodic shape oscillations.
We find a dissipative behavior of the wall motion in connection with the order-to-chaos
transition in the dynamics of the microscopic degrees of freedom.
12.1.7
Anharmonicities and non-linearities in the excitation of
Double Giant Resonances
M. V. Andrés, F. Catara, Ph. Chomaz, E.G. Lanza, C. Volpe
Nell’ambito di un approccio microscopico basato sulla RPA si sono studiati gli effetti
dell’anarmonicitá e della non lineariá sull’eccitazione Coulombiana di stati di multifononi
sui nuclei 208 Pb, 90 Zr, 96 Zr, 40 Ca e 28 O indotta dal un proiettile 208 Pb a 640 MeV/A. Le
anarmonicitá sorgono dall’introduzione dell’interazione residua che accoppia stati ad un
fonone con quelli a due e stati a due fononi tra di loro. Termini non lineari, negli operatori
di creazione ed annichilazione di fononi, sono stati introdotti nel campo esterno. Questi
termini non lineari e le anarmonicitá non sono prese in considerazione nell’approccio
52
standard dell’eccitazione di multifononi. Dai calcoli effettuati per la sezione d’urto di
eccitazione Coulombiana si possono estrarre numerosi esempi che mostrano l’importanza
delle innovazioni introdotte. Con questi nuovi termini la sezione d’urto aumenta rispetto
ai calcoli standard dal 10 fino al 20%, a secondo dei nuclei, nella regione di energia
della doppia risonanza gigante di dipolo (DGDR). Effetti importanti si trovano anche a
bassa energia. La sezione d’urto predetta nella regione DGDR é molto vicina ai dati
sperimentali.
12.1.8
Collective transition densities in neutron-rich nuclei
F. Catara, E.G. Lanza, M. A. Nagarajan, A. Vitturi
Nell’ambito della Random Phase Approximation si sono calcolate le transizioni di
densitá per nuclei ricchi di neutroni. L’introduzione del continuo é stata trattata facendo
uno sviluppo in funzioni di oscillatore armonico. Ci si é concentrati sugli stati che contribuiscono alla risonanza gigante di quadrupolo (GQR) e non sugli stati di bassa energia,
presenti per questi nuclei, ma il cui carattere collettivo é ancora in discussione. Si é
trovato che , ovuto al grande strato esterno di neutroni, i modi isoscalari e isovettoriali
sono generalmente fortemente mescolati. Si é altresı́mostrato che le transizioni di densitá
corrispondenti agli stati GQR possono essere ragionevolmente descritii dai modelli collettivi in termini di oscillazioni in fase o fuori fase delle densita’ di protoni e neutroni i quali
hanno raggi differenti.
12.1.9
Universal behavior of Lyapunov exponents in unstable
systems: ”Critical Chaos”.
M. Belkacem, A. Bonasera, V. Latora, A. Rapisarda
In the framework of Classical Molecular Dynamics, we studied the largest Lyapunov
exponent λ in correspondence of the critical behavior for two classical unstable systems of
particles having ’nuclear-like’ and ’atomic-like’ (4 He) interactions. Universal features were
found near the critical temperature. More precisely it was possible to fit the numerical
values with the the functional form λ ∼ |T −Tc |−ω with ω = 0.15 independent of the system
and the number of constituents. Loosely speaking we have found numerical evidence for
”critical chaos”. At temperature lower than the critical one we can fit both systems with
the form λ ∼ T 0.45 , a universal behavior typical of order-to-chaos transitions.
12.1.10
Semiclassical methods in heavy-ion chaotic scattering
M. Baldo, E. G. Lanza, A. Rapisarda
We investigated the quantum-classical correspondence in the problem of chaotic scattering for heavy ion reactions around the Coulomb barrier. By means of the Husimi
transform, classical trajectories are found to span the same phase space of the quantal
problem. These calculations confirm the validity of this powerful semiclassical method
and provide a stronger connection between classical chaotic scattering and the irregular
fluctuations found in the available experimental data.
53
12.1.11
Finite Size Effects in QGP
L. Lo Monaco
Si sono calcolati gli effetti dovuti alla grandezza finita di goccioline di plasma formato
da quark e gluoni (qgp). Il modello considera la partizione tra un sistema adronico
(essenzialmente pioni) e qgp formato in collisioni fra ioni pesanti ultrarelativistici. A sua
volta il qgp puf̀razionarsi in gocce separate. Si sono calcolate le frazioni di volume ed
energia, nonchè l’entropia per le diverse componenti di una fase mista qgp-π.
I risultati vengono confrontati i risultati con quelli ottenuti in “quark matter” (infinita).
Si trova che la temperatura e densità di energia del qgp sono molto maggiori a parità di
demsità di energia totale per il sistema. Tuttavia un sistema con molte piccole gocce di
plasma è sfavorito dal punto di vista dell’entropia.
12.1.12
Parton Modification Effects in Heavy Ion Collisions,
P. Castorina, A. Insolia and L. Lo Monaco.
Nuclear modifications of parton distributions are known to produce sizeable effects in
several processes like Deep Inelastic Scattering (DIS) and µ+ µ− production. Our aim is
to find which effects they produce in final states created by high energy reactions between
nuclei.
For this we insert a parametrization of nuclear parton distributions in a Montecarlo code
to simulate high energy collisions between nuclei. This parametrization accounts for most
precise data on DIS, Drell-Yan and J/Ψ production in nuclei and satisfies the EnergyMomentum Sum Rule (EMSR). The results show that the predicted values of energy
density, multiplicity and specific spectra produced in relativistic heavy ion collisions critically depend upon the treatment of the nuclear structure functions. If, as it seems, the
modification of parton distributions in the nuclear environment is a universal effect, it is
not surprising that this is the case. Therefore nuclear modifications of parton distributions must be accurately considered to distinguish between nuclear effects and possible
novel physics due to the qgp phase transition.
12.1.13
Parton Distributions and J/Ψ Suppression,
P.Castorina, A. Insolia and L. Lo Monaco.
The production rate of J/Ψ and Ψ0 mesons relative to Drell-Yan pairs is one of the
observables studied for the production of quark gluon plasma (qgp) in nucleus - nucleus
collisions. The suppression of these mesons with respect to the p-p collisions is seen
as a signal of the phase transition to qgp. Recent experiments with several nuclear
combinations (O + Cu, O + U and S + U) at Cern have led to the proposal of a variety of
alternative suppression mechanisms. Before concluding that qgp was formed, however, it
is necessary to consider more standard effects which could lead to the same suppression.
In this work we consider the modification of parton densities in nuclei and its effect on
J/Ψ and Ψ0 suppression. By doing so we can explain the recent experimental results and
the xF dependence of the Ψ0 over J/Ψ ratio, which is lacking in other proposed approaches
based on Glauber theory alone.
We conclude that most aspects of J/Ψ and Ψ0 production in p-nucleus and nucleus-nucleus
collisions can be accounted for by the combined effect of nuclear absorption and parton
modifications in nuclei, that is without invoking qgp formation.
54
12.1.14
Structure of Odd-A 1s0d and 1p0f-shell nuclei in the
Collective Pair Approximation
F. Catara, M. Sambataro
Si e’ studiata la struttura di nuclei con tre e cinque nucleoni attivi nelle shell 1s0d e
1p0f nell’ambito della ”Collective Pair Approximation”. Le coppie collettive sono state
determinate diagonalizzando l’hamiltoniana nello spazio di due nucleoni fuori delle shell
chiuse. Nuclei con 2k+1 nucleoni sono stati quindi descritti in termini di k coppie collettive
ed un nucleone. E’ stato mostrato che lo spettro di modello a shell per stati a bassa energia
di eccitazione puo’ essere ben riprodotto considerando soltanto un ristretto numero di
coppie collettive.
12.1.15
QRPA and beta decay physics: higher-order approximations in a boson formalism
M. Sambataro
La ”Quasiparticle Random Phase Approximation” (QRPA) e’ stata esaminata con
particolare riguardo alla fisica del decadimento beta. In quest’ambito, infatti, questa
teoria costituisce lo strumento base per la trattazione di tutti quei casi non accessibili
ai calcoli di modello a shell. La QRPA e’ stata rivista in un formalismo bosonico ed
approssimazioni di ordine superiore sono state prese in discussione. Dei test sulla validita’
di queste approssimazioni sono stati compiuti prendendo come riferimento un modello
schematico. I risultati relativi ad energie di eccitazione ed ampiezze di transizione beta
hanno rivelato sensibili miglioramenti rispetto ai valori QRPA.
12.1.16
Torwards a self-consistent Random Phase Approximation for Fermi systems
F. Catara, G. Piccitto e M. Sambataro
Presentiamo un metodo che consente di trattare correlazioni in sistemi fermionici finiti
piu’ consistentemente che nell’ambito della ”Random Phase Approximation” (RPA). Il
metodo non ricorre alla ”Quasi Boson Approximation” (QBA), dove valori di aspettazione
nello stato di base del sistema sono approssimati dai loro valori nello stato Hartree-Fock ,
ma piuttosto fa sempre uso dello stato correlato. Deriviamo un sistema di equazioni non
lineari che determina le energie e le funzioni d’onda degli stati eccitati cosi’ come i numeri
di occupazione nello stato di base. Come esempio, applichiamo una versione semplificata
del metodo allo studio di cluster metallici. Mostriamo che il metodo consente di migliorare
i risultati della normale RPA nei casi in cui la QBA e’ di dubbia applicazione.
12.1.17
Superfluidity of Nuclear Matter with realistic forces
U. Lombardo
The superfluid state of symmetric nuclear matter has been studied along with its limit
to low density which leads to the transition from Cooper pairs to deuteron matter. This
calculation has been extended to asymmetric nuclear matter where the reduction of the
55
phase space available for pairing correlations implies a strong suppression of superfluidity. Finite size effects have been also studied for a nucleus as well as a slab of muclear
matter. The screening of pairing interaction due to the induced interaction gives a strong
suppression of pairing in the channel 1S0 .
12.1.18
Equation of State of Nuclear Matter
U. Lombardo
The effect of three–body correlations in nuclear matter has been studied in the framework of the Brueckner theory with the gap choice as auxiliary potential. Ried soft core
and Argonne V14 potentials have been used in the calculations. The Brueckner theory
with continuous choince has been extended to include ground state correlations: the nuclear mean field and in–medium cross section have been selfconsistently evaluated for the
sake of application in transport model simulations of heavy ion collisions.
12.1.19
Transport Model of Heavy Ion Collisions
U. Lombardo
The equation of state based on the extended Brueckner theory has been used in the
transport model simulations of heavy ion collisions. The effect of the momentum dependence in the mean field on the transverse flow has been investigated. The results do not
support the presumed equivalence between a stiff equation of state and the repulsive effect
introduced by a momentum dependent potential. In addition, the medium effects on the
nucleon–nucleon scatterings have been proved to be very important for a good agreement
between the calculated and the experimental vanishing flow energies.
12.1.20
Astrophysical S(E) factor at very low energy: screening
effect or nuclear effect?
A. Scalia
Viene studiato l’andamento del fattore astrofisico nucleare S(E) ad energie molto basse
(E¡¡EB),in quanto recenti misure della sezione d’urto di fusione,nel caso di nuclei leggeri,hanno mostrato che il fattore astrofisico S(E) presenta un andamento crescente contrariamente a quanto veniva supposto in precedenza. Generalmente questo andamento
viene connesso allo ”screening” elettronico,ma calcoli effettuati nell’ambito della fisica
atomica non sono compatibili con l’effetto osservato.Lo studio viene effettuato usando il
modello ”ombra” per la fusione nucleare.
12.2
THEORETICAL PARTICLE PHYSICS
56
12.2.1
Phenomenology at LEP
A. Agodi, G. Andronico, M. Consoli
The data of the four experiments at LEP presented at the 1994 Glasgow Conference
and at the 1995 Winter Conferences have been analysed in order to get an estimate of
the Higgs mass. Moreover it has been pointed out that the determination of the strong
coupling constant at Z mass scale αs (MZ ) from the LEP data, is affected by substantial
systematic effects which cannot be interpreted within the gaussian statistics, therefore
yielding a poor estimate of this quantity. Thus, in it has been shown that, allowing for
the large range 0.113 < αs (MZ ) < 0.13, the fit to the LEP data is optimized by a value
of the Higgs mass in the range 500-1000 GeV, in agreement with the indications from the
W mass.
12.2.2
Scalar Theories on Lattice
A. Agodi, G. Andronico, M. Consoli
A Monte Carlo lattice computation of the effective potential (EP) has been performed
for λφ4 theories in four dimensions, both in the single component and in the O(2)symmetric cases. The results show that the one loop approximation to the EP reproduces
the data with much greater accuracy than the perturbatively improved expression of the
EP, obtained by resumming the leading log series. This computation is a clear indication
that the massless (λφ4 )4 theory undergoes Spontaneous Symmetry Breaking and, at the
same time, it is trivial, that is, the shifted field fluctuations around the true vacuum are
controlled by a quadratic hamiltonian. In this case, as already shown by M. Consoli and
P. Stevenson, the one-loop EP , in the continuum limit, becomes exact and the mass gap
stays finite while the coupling costant goes to zero.
12.3
THEORETICAL SOLID STATE PHYSICS
12.3.1
Polaronic theories in discrete systems with reduced dimensionality
R. Pucci, A. La Magna
The ground state of a quasiparticle (exciton, electron or hole) interacting with dispersionless optical vibrations or acoustic phonons of a one-dimensional chain has been
investigated using a variational approach, particularly in the Holstein model. Phase diagrams for the quasiparticle states depending on the values of the parameters of the system,
such as the nonabadiaticity parameter and the electron-phonon constant, have been obtained. In particular, the regions in the parameters space in which an almost free electron
state, a “small polaron,” or a spontaneously localized state have been distinguished.
The same question has been addressed in two-dimensional discrete lattices. A similar
variational technique gave evidence for the existence of travelling self-localized exciton
states, when a Frölich coupling with acoustic phonons is allowed.
57
Numerical studies for the dynamical evolution of coupled states between single excitations and a two-dimensional discrete lattice have been performed, allowing for an
extensive threshold study for the soliton generation.
The relevance of such models in physical systems with reduced dimensionality, such
as molecular chains and high-Tc superconductors, has been discussed.
12.3.2
Interplay between correlation and disorder in electronic
systems.
F. Siringo
Sono stati studiati diversi aspetti teorici dei sistemi elettronici disordinati.
• a) Proprietà di trasporto: facendo ricorso anche a nuove tecniche diagrammatiche,
con particolare enfasi per le regioni critiche.
• b) Proprietà magnetiche: con particolare riferimento ai semiconduttori compensati,
utilizzando una nuova teoria di campo medio già messa a punto per lo studio delle
leghe liquide.
• c) Superconduttività: si è intrapreso uno studio degli effetti del disordine sulle
proprietà superconduttive.
12.3.3
Statistical models for molecular ordering.
F. Siringo
Sono stati proposti e studiati dei semplici modelli per la descrizione dell’ ordinamento
molecolare in sistemi frustrati. I metodi utilizzati vanno dalla semplice approssimazione
di campo medio, al gruppo di rinormalizzazione.
12.3.4
High Tc Superconductors
G. Angilella, R. Pucci and F. Siringo
Si è discussa la relazione esistente fra temperatura critica, concentrazione di portatori e pressione negli HTCS, utilizzando un modello di Hubbard esteso, e discutendo la
competizione fra la formazione di gap con simmetria s e simmetria d.
È in corso di studio la generalizzazione di tale modello al caso dei sistemi stratificati
(layered superconductors), ove sia rilevante il tunneling di coppie fra piani.
12.3.5
Molecular Systems under High Pressure
R. Pucci, F. Siringo
The extended Hubbard Hamiltonian on a bcc lattice has been studied at half-filling in
mean-field approximation. The results lead to the prediction of an ionic insulating brokensymmetry phase for any hydrogenoid bcc solid for 1.0 < rs < 2.6. The occurrence of such
a phase would explain the failure to achieve hydrogen metallization at high pressure.
Moreover, a metal-insulator transition is expected for sodium in the 100 GPa region.
58
12.3.6
Correlations in Molecular Systems
R. Pucci, A. Grassi, G.M. Lombardo, N.H. March
The study of correlation energies is pursued on in both hetero- and homonuclear diatomics. Scaling similarities have been revealed for light homonuclear diatomics, following
first-principles calculations of atomic correlation energies.
12.3.7
Ionization and Excitation Energies of Molecules and Microcluster
P. Tomasello, D. Gutkowski
Si sono conculsi e definiti gli studii sulle proprietá elettroniche fondamentali, energie di
ionizzazione e di eccitazione, del complesso MoF6 e della sua forma ossidata MoOF4. Tali
studii, i cui risultati sono apparsi e/o appariranno in riviste internazionali, sono i primi
ad essere condotti su questa molecola per mezzo di hamiltoniane ab-initio e all-electron
ed impieganti tecniche computazionali tra le piú sofisticate ed affidabili nel campo della
fisica molecolare teorico-computazionale. Per mezzo di essi é adesso possibile una interpretazione ragionata degli esperimenti PES ed U.V. che ha condotto ad una asseganzione
e caratterizzazione inequivoca dei picchi principali delle funzioni spettrali registrate. Parallelamente si é iniziato un nuovo studio sui potenziali di ionizzazione principali di una
serie molecolare, quella dei tiazilalogenuri, i cui componenti di piú interesse sono stati
sintetizzati solo ngli ultimi tre-quattro anni. I risultati ottenuti, sempre con tecniche
di stato dell’arte, sono molto incoraggianti e presentemente vengono considerati per una
possibile pubblicazione.
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12.4
C4 - GENERAL ARGUMENTS IN THEORETICAL PHYSICS
12.4.1
Multiscale Expansions and Integrability
P. M. Santini
È ben noto che l’effetto di una non linearità debole (dell’ordine ²) sulla propagazione
di onde dispersive, nell’ approssimazione monocromatica, è quello di far sı̀ che l’ampiezza
dell’onda subisca una modulazione su un’opportuna scala spazio-temporale lunga. Tale
modulazione è descritta, al 1o ordine in ², dall’equazione di Schrödinger non lineare. Si
sono studiati gli effetti di ordine superiore al primo, costruendo i termini successivi dello
sviluppo asintotico della soluzione per uno spazio delle fasi più ampio, comprendente, oltre
al caso di spettro puramente continuo (caso di radiazione pura) anche quello di spettro
discreto semplice (un solo stato legato (un solitone)). In queste due situazioni l’evoluzione
dell’ampiezza di modulazione su scale temporali sempre più lunghe è descritta dai flussi
integrabili della gerarchia (le simmetrie) dell’equazione di Scrödinger non lineare. Gli
ingredienti chiave di questa teoria sono l’integrabilità dell’equazione di Schrödinger non
lineare e l’algebra abeliana infinito-dimensionale delle sue simmetrie.
12.4.2
Explicit Solutions of Model Evolution Equations in 2+1
Dimensions
P. M. Santini
Si e’ affrontato lo studio dell’equazione di Davey-Stewartson (DS):
1
iqt + (qxx + σ 2 qyy ) − (φx + |q|2 )q = 0
2
φxx − σ 2 φyy = −2σ 2 (|q|2 )x
nei due casi σ 2 = 1 (DSI) e σ 2 = −1 (DSII). Tale equazione e’ una generalizzazione
integrabile a 2+1 dimensioni dell’equazione di Schrödinger no n lineare e ha applicazioni
in Fluidodinamica, Fisica dei Plasmi ed Ottica non lineare. In un contesto fluidodinamico,
in particolare, l’equazione di DSII descrive l’evoluzione di ond e di superficie di ampiezza
complessa q(x, y, t), in interazione col campo di velocit à (φx , φy ), φ = φ(x, y, t), nel caso
in cui la forza di gravità prevale sulla tensione superficiale; mentre l’equazione di DSI
descrive la situa zione opposta. Si e’ studiata una nuova classe di soluzioni localizzate
dell’equazione di DSII (ottenute mediante uno schema Wronskiano), che esibiscono un
comportamento più ricco di quelle note, i cosidetti “lumps” (strutture coerenti che vanno
a zero come 1/r2 e non interagiscono tra di loro). Anche le nuove soluzioni vanno a zero
razionalmente, ma sono localizzate in modo arbitrariamente forte, come 1/rN , N ≥ 2 per
r → ∞; inoltre la loro interazione, non banale, consiste in urti frontali con scattering ad
angolo retto. Quest’ultimo fenomeno è stato anche osservato numericamente in diverse
teorie di campo in 2+1 dimensioni.
12.4.3
Linear Theories and their Symmetries
P. M. Santini
60
Data una teoria, descritta da un sistema di equazioni lineari, si è studiato il modo in
cui le soluzioni di tali equazioni possono dipendere da una o più variabili nascoste (cioè
non presenti esplicitamente nel sistema di equazioni). Si è mostrato che tale dipendenza
è descritta da equazioni non lineari integrabili; in particolare, nel caso dell’equazione di
Schrödinger in n dimensioni, tale dipendenza è descritta da una equazione di Liouville
integrabile in n + 1 dimensioni.
12.5
C5 - INTERDISCIPLINAR SUBJECTS
12.5.1
Discrete Geometry and Integrability
A. Doliwa, J. Cieslinski, S. V. Manakov, M. Manas, P. M. Santini
La geometria gioca un ruolo rilevante nella fisica teorica moderna. Questa ricerca è
volta a generalizzare i concetti ed i risultati principali della geometria differenziale ad un
contesto discreto. I risultati hanno applicazioni potenziali in teoria dei campi, nelle teorie
di gauge su reticolo e d in Meccanica Statistica. La teoria dei sistemi di equazioni non
lineari integrabili ha un ruolo da protagonista in questo studio. 1) Ha generalizzato ad un
contesto discreto la nozione di “coordinate curvilinee coniugate”, introducendo la nozione
di “reticolo quadrilaterale multidimensionale”. Ha inoltre mostrato che tale reticolo è
caratterizzato da un sistema di equazioni non lineari integrabili alle differenze finite in un
numero arbitrario di dimensioni.
2) Ha costruito, in collaborazione con M. Manas e A. Doliwa, una generalizzazion e
vettoriale delle trasformazioni di Darboux per il reticolo quadrilaterale multidimensionale.
Tali trasformazioni permettono di costruire una nuova soluzione (un nuovo reticolo), a
partire da una soluzione nota, attraverso
la risoluzione di equazioni lineari. Ha anche costruito le rappresentazioni di Gramm,
Wronski e Casorati di tale reticolo. Ad illustrazione del metodo, ha introdotto e studiato
il reticolo costituito da parallelogrammi e quello dromion ico.
3) Ha mostrato, in collaborazione con J.Cieslinski e A.Doliwa, che l’analogo dis creto
ei sistemi di coordinate ortogonali in N dimensioni è costituito da reticol i quadrilaterali
N - dimensionali caratterizzati dal vincolo che ogni quadrilate ro elementare è iscritto in
un cerchio. Le equazioni alle differenze che caratterizzano tali reticoli, essendo riduzioni
opportune delle equazioni de l reticolo quadrilaterale, costituiscono quindi un sistema di
equazioni non linear i alle differenze finite integrabili.
4) In collaborazione con A. Doliwa e S. Manakov, ha applicato una recente tecnic
¯ al sistema di
a di riduzione di equazioni non lineari integrabili, basata sul problema ∂,
equazioni discrete che caratterizzano il reticolo quadrilaterale multidimensionale, ottenendone una vasta classe di riduzioni. Ha poi studiato le proprietà geometriche dei correspondenti reticoli ridotti, individuando tra qu esti il reticolo circolare multidimensionale
ed ottenendo per tale reticolo una parametrizzazione conveniente.
61
12.6
C6 - GENERAL ARGUMENTS IN THEORETICAL PHYSICS
12.6.1
Tunnelling times
F. Raciti
The problem of defining the duration of a tunnelling event is still unsolved and there is
no clear interpretation for the extremely short times which have been measured recently
by several experimental groups. In order to shed some light on the Hartman effect (very
short tunnelling times) we have proposed new definitions for the penetration and return
times inside the barrier. Moreover, in our opinion, it is very important to study the
variances and not only the mean tunnelling time. Thus, we have analysed, for a square
potential barrier, the evolution of a gaussian wave packet inside the barrier and calculated,
not only the mean tunnelling times, but also the variances. Our results are consistent
with the asymptotic analysis of the Hartman effect.
12.6.2
Quantum Chaos
M. Baldo e F. Raciti
The general problem of quantum manifestations of chaos has been considered within
the semiclassical approximation. In particular we have found a method which allows to
build wavepackets which are localised around a classical periodic orbit in a circular billiard
and whose quantal lifetime is arbitrarily large. The generalization of the method to non
integrable billiards is under investigation.
62
Chapter 13
AREA D: SOLID STATE PHYSICS
13.1
High temperature superconductivity
G.Burrafato, S.O. Troja, E.Turrisi, L. Arcidiacono, C. Caputa, A. M. Gueli,
M. R usso.
The thermally stimulated luminescence of oxides, carbonates and high Tc ceramic
superconductors BSCCO-Pb doped obtained by solid state reaction was measured in the
temperature interval 20-500 C. The glow curves obtained on superconductors are composed with those of starting reagents. The analysis of the data evidences the possibility
of characterising the oxides and carbonates and of detecting very low intensity TL signal
produced in the supercondunctors by spurious compounds, which can be identified in some
cases. Thin films of BSCCO (n=2) are grown by pulsed laser ablation on single cristal
MgO(100) using an excimer laser XeCl (l =308 nm). The structure and the morfology
of films are analyzed by X-ray diffraction and scanning electron microscopy. The composition of samples is investigated by EDX and RBS analysis. We examined the influence
of both substrate temperature and energy density of laser beam on the films obtained in
a fixed geometry arrangement and in 0.1 mbar oxygen pressure. By characterising the
films quality by some electrical properties as the onset of the superconducting transition
Tconset , the transition width DTc and the temperature Tco where the resistence is zero,
we found the best result at Tsubs = 700 C and energy fluence of 0.95 J/cm2 obtaining
a film with Tco = 75 K and DTc = 10 K, and (ab) plane parallel to the surface of the
substrate. Further investigations are oriented to correct the deviations from stoichiometry
resulting from EDX analysis by using various attempts (non stoichiometric target, proper
Pb doping in post-annealing process ... ).
13.2
D - Analysis of measurements criteria of acoustic urban noise
G.Burrafato, S.O. Troja, E.Turrisi, L. Arcidiacono, C. Caputa, A. M. Gueli,
M. R usso.
In the urban noise measurament the aestimate of vehicular traffic contribution is often
done by measuring the noise level in a short period of time. In our work the significance of
63
A-weighted equivalent continous sound level value LAeq(T) by urban traffic noise averaged
over short period of time is analized with respect to the daily value LAeq(D) averaged over
the reference period as defined by current italian law order (D.P.C.M. 1.03.91). Various
sites located in Catania city have been examined by weekly monitoring the traffic noise.
The LAeq(D) value is verystable from Monday to Friday in all the sites tested (oscillation
lower than 0.5 dBA). The differences of the LAeq(T) values, for T= 15, 30 and 60 minutes,
and corresponding LAeq(D) have been calculated and examined by analisis of variance.
The statistical omogeneity of distribution of the observed deviations allow to c alculate
the probability in obtaining an estimate of LAeq(D) within some fiducial limits by short
term averaging. For instance, an averaging time of 30 minutes beetween the 8 a.m. to
10 a.m. and 4 p.m. to 8p.m. gives over 90from LAeq(D) in all sites tested. A similar
analisys for the night period show very large fluctuation of short term value. In order
to give a correct aestimate it is necessary to average over the whole period. Besides the
nights averaged value LAeq(N) is unstable among the weak period. Further investigations
are developping to charaterize the time behavior of traffic noise in different type of site
in order to find some reliable measuring strategy alternative to continuous monitoring.
13.3
Electrochromic materials
A. Pennisi, F. Simone
La ricerca riguarda l’analisi delle proprietà fisiche di films di ossido di Tungsteno
(WO3) depositati per sputtering a r.f. L’applicazione di tensioni di basso valore permette
di commutare lo stato di colorazione del dispositivo da scolorato a colorato e viceversa. Per
attivare la formazione dei centri di colore nello strato elettrocromico necessario la presenza
di un conduttore ionico, in quanto tale formazione causata dall’inserzione di ioni in seno
al materiale. Vengono analizzate anche le caratteristiche morfologiche delle superfici e la
loro correlazione con l’efficienza di colorazione dei dispositivi. Inoltre la caratterizzazione
dal punto di vista elettrochimico consente il calco lo della carica scambiata all’interfaccia
e la determinazione dei potenziali tipici della transizione elettrocromica.
13.4
Interfaces and oxidation states.
G. Faraci, A. R. Pennisi
E’ stata studiata l’interfaccia Ge-Cs mediante spettroscopia dei livelli di core Ge 3d,
Cs 4d e banda di valenza. Tali misure sono state effettuate con luce di sincrotrone
presso Elettra-Trieste, per diversi spessori dello strato metallico evaporato sulla matrice monocristallina di germanio. Sono stati evidenziati i legami che si stabiliscono
all’interfaccia tra il metallo ed il semiconduttore: la deconvoluzione dei livelli di core
ha mostrato due componenti di tipo ionico e di tipo covalente la cui evoluzione e’ stata
studiata in funzione dello spessore di metallo dal regime di clusters a quello di monolayer.
In seguito ad esposizione controllata in atmosfera di ossigeno, sono stati anche investigati
gli stati di ossidazione substechiometrica del Ge che si formano sull’interfaccia.
13.5
Catalysis
64
L’effetto catalizzatore di metalli alcalini (Na, Cs) depositati in quantita’ inferiore al
monostrato su metalli o semiconduttori e’ stata approfondita in relazione alla ossidazione
controllata dei diversi substrati. Tra tali substrati, oltre al GaAs e’ stato studiato il
Ge(100) osservando le diverse componenti presenti nel livello di core Ge 3d. Queste
componenti sono state individuate con la loro energia di legame, e la relativa larghezza di
banda.
13.6
Clusters
Da spettri Cs 4d effettuati mediante spettroscopia di fotoemissione ad energia di fotone
intorno a 110 eV a temperatura ambiente, su deposizioni in regime di clusters, e’ stato
ottenuto un branching ratio pari a 4/3 invece dell’ usuale 3/2 previsto dalla meccanica
quantistica. A bassa temperatura tale valore e’ ottenuto anche dalla componente superficiale dello strato spesso, mentre il bulk segue il valore statistico del rapporto spin-orbita.
Tali risultati sono interpretati mediante ”relativistic random phase approximation” per i
diversi canali di fotoionizzazione in vicinanza al minimo di Cooper.
13.7
Erbium Luminescence in Silicon
S. U. Campisano, F. Priolo, E. Rimini
Integrated optical devices have several attractive characteristics such as a very high
rate of data transmission in optical waveguides and low sensitivity to electromagnetic
radiation. Many applications, such as optical interconnections at the chip-to-chip level,
requires the optimization of active and passive optical functions (e.g. light sources, waveguides, modulators and detectors), and their integration together with electronic functions
on the same chip. Being Si the semiconductor with the most mature technology, it would
be the material of choice for a monolithic integration of optical and electrical functions.
However, due to its indirect band gap and to the absence of linear electro-optic effect, Si
has been considered for a long time unsuitable for optoelectronics applications. We have
proposed a solution to the problem of light emission from Si through the incorporation
of Er, a rare earth ions, in the silicon lattice. Er ions are characterized by an unfilled
4f shell surrounded by an external close shell. A sharp, atomic-like radiative transition
within the 4f shell of these ions can be excited both optically and electrically. We have
solved the major problems hampering the observation of intense room temperature light
emission (i.e. the temperature quenching of the luminescence and the low concentration
of optically active ions that can be incorporated in Si) by using co-doping with O. The
beneficial effect of O is due to the formation of Er-O complexes, as demonstrated by
high resolution photoluminescence, deep-level transient spectroscopy and electronic paramagnetic resonance measurements. Moreover, we have designed and fabricated Er-doped
silicon LED at 1.54 µm operating with a high quantum efficiency (¿1.5 × 10− 4) at room
temperature.
13.8
High energy implantation and defects
S. U. Campisano, F. Priolo, E. Rimini
65
Silicon is the key material in the semiconductor industry and ion implantation is the
technique normally used to dope this material. Understanding the numerous and complex
phenomena occurring during ion implantation in silicon is therefore a crucial issue from
both a fundamental and a technological point of view. This subject has been under
investigation at the Department of Physics for several years, and several phenomena,
including radiation enhanced diffusion, ion beam induced crystallization, amorphization,
doping, defect generation etc., have been analyzed in details. Studies during 1995 have
mainly focused on ion beam induced nucleation and point defect migration. Irradiating an
amorphous silicon layer at temperatures of 500o C stimulates the nucleation and growth of
crystalline grains embedded in the amorphous matrix. Eventually the process can lead to
the complete crystallization of the layer with the formation of polycrystalline silicon. This
process should be compared with the pure thermal nucleation and growth which occurs
at temperatures above 650oC. Indeed, ion irradiation enhances the nucleation process
by more than 9 orders of magnitude over the pure thermal values. The dependencies of
this process on ion mass, dose, dose rate, nuclear energy deposition and temperature have
been analyzed. The results have been explained on the basis of a phenomenological model
in which the thermodynamic barrier for nucleation is modified by irradiation. Another
subject of intense investigation has been the generation and migration of point defects in
crystalline silicon. We have demonstrated that low energy ion implantation (for instance
40 keV Si ions Rp 60 nm) can inject interstitials in the silicon matrix migrating at room
temperature for distances as long as several microns. The interaction of these injected
interstitials with impurities (such as C and O), dopants (such as B and P) and preexisting defect distributions (such as divacancies and phosphorus-vacancy complexes) have
been investigated. From these data it has been possible to estimate a lower limit to the
diffusivity of interstitials in crystalline silicon and at room temperature. The value is
10-11cm2/s. This direct estimation of such an important physical quantity is particularly
interesting since values reported in the literature, mainly based on extrapolations from
high temperature data, are scattered over more than 20 orders of magnitude.
66
Chapter 14
AREA E: GENERAL PHYSICS
14.1
Fractal clustering in seismicity temporal distribution (1989-1994) of the low eastern flank of
Mt. Etna
V. Latora, A. Rapisarda, S. Vinciguerra
An investigation on the time clustering properties of the seismicity affecting the low
eastern flank of Mt. Etna during the period 1989-1994 was performed. It was analysed
a catalog of microearthquakes and located earthquakes recorded by the four stations of
the Osservatorio Sismologico di Protezione Civile di Acireale. Through a fractal analysis
it was found that these temporal distributions are not periodic nor random and present
scale-invariant time clustering which can be characterized by a fractal dimension. The
fractal clustering is stronger just before major eruptions.
14.2
Multimedia software packages and their test in
the teaching of Physics (both in university courses
and in secondary school)
D. Alloro, C. Lo Presti, G. D. Maccarrone, S. Pappalardo, C. Petta, S. Reito
14.3
Study of the newtonian analysis of circular motion in relation to the writings of Descartes and
Huygens,
S. Albergo, A. Ciancitto, E. Giannetto, P. Di Mauro, G. D. Maccarrone, S.
Notarrigo, A. Pagano, S. Pappalardo, G. Stratan, A. Tiné, A. Zuccarello
We have shown that Newton’s work originates from the necessity of a logical settlement of the causal relations between the centripetal force, the circular motion and the
67
centrifugal force. We have shown that this logical settlement (to assign to centrifugal
force a non-contradictory function in dynamics) lead Newton to a well-developed inertial
mechanics.
Some fundamental stages of the crisis of newtonian mechanics, at the beginning of the
XXth century, and the resulting achievement of relativistic and quantum paradigms have
been studied. Both experimental and theoretical aspects of such a crisis have been analysed by means of G. Peano’s deductive logic. In order to single out historical and philosophical elements, wich allowed the development and the crisis of determinism, the works
of most important classical and modern scientists (Newton, Poincare’, Einstein, Born,
Bridgman, . . . ) have been analysed from a historical and epistemological point of view.
14.3.1
Cultural exploitation of the ancient scientific material
(instruments, books, reviews, etc.) owned by the Department of Physics and the Astrophysical Observatory
of Catania,
C. Lo Presti, F. Bevilacqua, E. Giannetto, G. D. Maccarrone, S. Pappalardo,
C. Petta, S. Reito
Cataloguing and restoration of instruments and books; study of the connection with
the physical researches of the Nineteenth Century and early Twentieth Century.
68
Chapter 15
Publications in APPLIED PHYSICS
1996
1. C.Arcidiacono, G.Cascone, C.R.Fichera and D.Gutkowski:
Regimi Termici di Terreni Pacciamati sotto Serra
Colture Protette 7/8, 79-87 (1996)
2. S. Lombardo e S. U. Campisano:
Electrical and optical properties of semi-i polycrystalline silicon thin films. Role of
microstructure and doping
Ma Science and Engineering Reports 19, 1, (1996)
3. S. Lombardo, K. Kyllesbech Larsen, V. Raineri, F. La Via, S. U. Campisano, S.
Lagomarsino, e A. Kazimirov:
Characterization of C co-implanted GexSi1-x layers formed by high dose Ge implantation in (100) Si
J. Appl. Phys. 79 (1996)
4. S. Lombardo, A. Pinto, V. Raineri, P. Ward, G. La Rosa, G. Privitera, e S. U.
Campisano:
Si/GexSi1-x heterojunction bipolar transistors with the GexSi formed by Ge ion
implantation in Si
IEEE Electron Device Lett. 17, 485
5. S. Lombardo, V. Raineri, F. La Via, F. Iacona, S. U. Campisano, A. Pinto, and P
Ward:
Ge ion implantation in Si for the fabrication of Si/GexSi1-x heteroj transistors
Mat. Chem. Phys. 46, 156-160, (1996)
6. S. Lombardo, V. Raineri, R. Portoghese, S. U. Campisano, A. Pinto, G. La Rosa,
Ward:
Characterization of Si/GexSi1-x heterojunction bipolar transistors Ge ion implantation in Si
Nucl. Instr. Meth. B 120, 169-172, (1996)
69
7. F. Iacona, S. Lombardo and S.U. Campisano:
Characterization by x-ray photoelectron spectroscopy of the chemical structure of
semi-insulating polycry silicon thin films
J. Vac. Sci. Technol. B 14, 2693-2700, (1996)
8. S. Lombardo, A. Cacciato, K. Kyllesbech Larsen, V. Raineri, F. La Via, V. Privi S.
U. Campisano:
High temperature annealing effects on the electrical char of C implanted Si
J. Appl. Phys. 79 , 3464, (1996)
9. V. Raineri and S.U. Campisano:
Secondary defects dissolution by voids
Appl. Phys. Lett. 69, 1783-1785, (1996)
10. C. Spinella, V. Raineri, F. La Via, and S. U. Campisano:
Two-dimensional j profiling by selective chemical etching: applications to electron
devic characterization
J. Vac. Sci. Technol. B 14, 414, (1996)
11. S. Lombardo, S. U. Campisano, G. N. van den Hoven and A. Polman: Electroluminescence of erbium in oxygen doped silicon
Mat. Res. Soc. 422, 333, (1996)
12. F. La Via and E. Rimini:
Electrical characterization of Ultra-Shallow Junc formed by diffusion from a CoSi2
source
Mat. Res. Symp. Proc. vol. 427, 4 (1996)
13. K. Kyllesbech Larsen, F. La Via, S. Lombardo, V. Raineri, R. A. Donaton e S. U.
Campisano:
Titanium Silicidation and Secondary Defect Annhilation in Ion B Processed SiGe
Layers
Mat. Res. Soc. Symp. Proc. vol. 402, 149, (1996)
14. A. La Ferla, G. Galvagno, S. Rinaudo, V. Raineri, G. Franco, M. Camalleri, A.Gasparotto,
A. Carnera and E. Rimini:
Ion implantation and diffusion of SiO2/Si system
Nucl. Instr. Meth. Phys. Res. B 116, 378-381, (1996)
15. F. Priolo, C. Spinella, E. Albertazzi, M. Bianconi, G. Lulli, R. Nipoti, J.K.N. Lindner, A. Mesli, R.C. Barklie, L. Sealy, B. Holm, A. Nylandsted Larsen
Ion Implantation Induced Damage in Relaxed Si.75 Ge.25 ;
Nucl. Instrum. Meth. B 112, 301 (1996)
70
16. C. O’Raifeartaigh, R.C. Barklie, A. Nylandsted Larsen, F. Priolo, G. Franzó, G.
Lulli, M. Bianconi, J.K.N. Lindner, F. Cristiano, P.L.F. Hemment
2 MeV Si Ion Implantation Damage in Relaxed Si1−x Gex ;
Nucl. Instrum. Meth., 120, 165 (1996)
17. A. Carnera, B. Fraboni, A. Gasparotto, F. Priolo, A. Camporese, G. Rossetto, C.
Frigeri, A. Cassa
Dose and Doping Dependence of damage Annealing in Fe MeV Implanted InP; in
Ion-Solid Interactions for Materials Modification and Processing, edited by D. Ila,
L.R. Harriot, D.B. Poker, Y.T. Cheng, T.W. Sigmon (Materials Research Society,
Pittsburgh, USA, 1996)
Mat. Res. Soc. Symp. Proc., 396, 829 (1996)
71
Chapter 16
Publications in EXPERIMENTAL
PHYSICS 1996
18. Sl. Cavallaro, E.De Filippo, G. Lanzanó, A.Pagano, M.L. Sperduto, R. Dayras,
R.Legrain, E. Pollacco, C.Beck, B. Djerroud, R. M. Freemann,A. Hachem, F. Haas,
B. Heusch and A. Morsad.
Fusion and binary mechanism competition in the
MeV/A.
35
Cl+24 Mg reaction at E/A≈8
Nucl. Phys. A583,161(1995), and submitted to Phys. Rev. C.
19. R. Nouicer, C. Beck, D. Mahboub, T. Matsuse, B. Djerroud, R. M. Freeman, A.
Hachem, Sl. Cavallaro, E. De Filippo, G. Lanzano’, A. Pagano, M.L. Sperduto, R.
Dayras, E. Berthoumieux, R. Legrain and E. Pollacco.
Statistical binary decay of
35
Cl +24 M g at ≈8 MeV/nucleon
Z. Phys. A356 7(1996).
20. C.Beck,....Sl.Cavallaro,...,
35
Cl +12 C asymmetrical fission excitation functions
Phys. Rev. C54 (1996)227.
21. R.Nouicer...Sl.Cavallaro...., Statistical binary decay of 35 Cl+24 M g at 8MeV/nucleon
Zeit Phys A, A356 (1996)4.
22. K.A. Farrar,.....Sl. Cavallaro..,
Fission decay of
48
Cr at E∗ ≈ 60 MeV
Phys. Rev. C54 (1996)1249.
23. S.Costa, S.Albergo, A.Insolia, C.Tuvè (Editors)
Critical Phenomena and Collective Observables
Proceedings of the
1st Catania Relativistic Ion Studies (CRIS ’96)
Acicastello, Italy, May 27-31, 1996
World Scientific (Singapore, 1996)
72
24. C.N.Knott, S.Albergo, Z.Caccia, C.-X.Chen, S.Costa, H.J.Crawford, M.Cronqvist,
J.Engelage, P.Ferrando, R.Fonte, L.Greiner, T.G.Guzik, A.Insolia, F.C.Jones, P.J.Lindstrom,
J.W.Mitchell, R.Potenza, J.Romanski, G.V.Russo, A.Soutoul, O.Testard, C.E.Tull,
C.Tuvé, C.J.Waddington, W.R.Webber and J.P.Wefel (The Transport Collaboration)
Interactions of Relativistic Neon to Nickel Projectiles in Hydrogen, Elemental Production Cross Sections
Physical Review C, 53 (1996) 347
25. S.Wang, M.A.Lisa, S.Albergo, F.Bieser, F.P.Brady, Z.Caccia, D.A.Cebra, A.D.Chacon,
J.L.Chance, Y.Choi, S.Costa, J.B.Elliott, M.L.Gilkes, J.A.Hauger, A.S.Hirsch, E.L.Hjort,
A.Insolia, M.Justice, D.Keane, J.Kintner, V.Lindenstruth, H.Liu, H.S.Matis, M.McMahan,
C.McParland, D.L.Olson, M.D.Partlan, N.T.Porile, R.Potenza, G.Rai, J.Rasmussen,
H.G.Ritter, J.Romanski, J.L.Romero, G.V.Russo, R.P.Scharenberg, A.Scott, Y.Shao,
B.K.Srivastava, T.J.M.Symons, M.L.Tincknell, C.Tuvé, P.G.Warren, D.Weerasundara,
H.H.Wieman, and K.L.Wolf (EOS Collaboration)
In-plane Retardation of Collective Expansion in Au + Au Collisions
Physical Review Letters, 76 (1996) 3911
26. J.A.Hauger, S.Albergo, F.Bieser, F.P.Brady, Z.Caccia, D.A.Cebra, A.D.Chacon,
J.L.Chance, Y.Choi, S.Costa, J.B.Elliott, M.L.Gilkes, A.S.Hirsch, E.L.Hjort, A.Insolia,
M.Justice, D.Keane, J.C.Kintner, V.Lindenstruth, M.A.Lisa, U.Lynen, H.S.Matis,
M.McMahan, C.McParland, W.F.J.Müller, D.L.Olson, M.D.Partlan, N.T.Porile,
R.Potenza, G.Rai, J.Rasmussen, H.G.Ritter, J.Romanski, J.L.Romero, G.V.Russo,
H.Sann, R.Scharenberg, A.Scott, Y.Shao, B.K.Srivastava, T.J.M.Symons, M.Tincknell,
C.Tuvé, S.Wang, P.Warren, H.H.Wieman, and K.Wolf (EOS Collaboration)
Dynamics of the Multifragmentation of 1A GeV Gold on Carbon
27. J.B.Elliott, S.Albergo, F.Bieser, F.P.Brady, Z.Caccia, D.A.Cebra, A.D.Chacon, J.L.Chance,
Y.Choi, S.Costa, M.L.Gilkes, J.A.Hauger, A.S.Hirsch, E.L.Hjort, A.Insolia, M.Justice,
D.Keane, J.C.Kintner, V.Lindenstruth, M.A.Lisa, U.Lynen, H.S.Matis, M.McMahan,
C.McParland, W.F.J.Müller, D.L.Olson, M.D.Partlan, N.T.Porile, R.Potenza, G.Rai,
J.Rasmussen, H.G.Ritter, J.Romanski, J.L.Romero, G.V.Russo, H.Sann, R.Scharenberg,
A.Scott, Y.Shao, B.K.Srivastava, T.J.M.Symons, M.Tincknell, C.Tuvé, S.Wang,
P.Warren, H.H.Wieman, and K.Wolf (EOS Collaboration)
Individual Fragment Yields and the Determination of the Critical Exponent Sigma
Physics Letters B, 381 (1996) 35
28. C.Tuvé for the Transport Collaboration:
C.Tuvé , S.Albergo, D.Boemi, Z.Caccia, C.-X.Chen, S.Costa, H.J.Crawford, M.Cronqvist,
J.Engelage, P.Ferrando, L.Greiner, T.G.Guzik, A.Insolia. F.C.Jones, C.N.Knott,
P.J.Lindstrom, J.W.Mitchell, R.Potenza, S.Reito, J.Romanski, G.V.Russo, A.Soutoul,
O.Testard, C.E.Tull, C.J.Waddington, W.R.Webber, J.P.Wefel, X.Zhang
Inclusive Neutron Spectra from the 40 Ca + H reaction at Elab = 357 and 565
MeV/amu
34th International Winter Meeting on Nuclear Physics
Bormio, Italy, 22 -27 January 1996
Proceedings, pag. 179
73
29. J.A.Hauger, Y.Choi, J.B.Elliott, M.L.Gilkes, A.S.Hirsch, E.L.Hjort, N.T.Porile,
B.K.Srivastava, R.Scharenberg, M.L.Tincknell, P.Warren, S.Albergo, Z.Caccia, S.Costa,
A.Insolia, R.Potenza, J.Romanski, G.V.Russo, C.Tuvé, F.P.Brady, D.A.Cebra, J.L.Chance,
J.C.Kintner, M.D.Partlan, J.L.Romero, V.Lindenstruth, W.F.J.Müller, H.Sann, M.Justice,
D.Keane, A.Scott, Y.Shao, S.Wang, F.Bieser, M.A.Lisa, H.S.Matis, M.McMahan,
C.McParland, D.L.Olson, G.Rai, J.Rasmussen, H.G.Ritter, T.J.M.Symons, H.H.Wieman,
T.Weinold, A.D.Chacon, K.Wolf
Excitation Energy, Temperature, and Density in the Multifragmentation of Gold
Nuclei
”Critical Phenomena and Collective Observables”
edited by S.Costa, S.Albergo, A.Insolia, C.Tuvè
World Scientific (Singapore, 1996), pag. 36
30. M.L.Tincknell and J.B.Elliott for the EOS Collaboration
Critical Exponents and the Scaling Function in Nuclear Multifragmentation of 1
AGeV Au + C
31. B.K.Srivastava for the EOS Collaboration
Nuclear Multifragmentation: Comparison between EOS data of Au+C at 1 GeV/nucleon
and a Statistical Fragmentation Model
32. R.Lacey for the EOS Collaboration
The Role of Thermally Driven Expansion in 1 AGeV Au + C
33. A.D.Chacon and the EOS Collaboration
The Hanbury-Brown-Twiss Effect at Bevalac Energies
34. Daniel Cebra and Jessica Kintner for the EOS Collaboration
Collective Effects of Pions at 1.15 GeV/nucleon Au + Au
74
35. Alessia Tricomi per la Collaborazione EOS
Temperature ed entropie dedotte dai rapporti di resa dei frammenti leggeri nella
collisione Au+C ad 1 GeV/n
Comunicazione al LXXXII Congresso Nazionale della Societá Italiana di Fisica
Verona, 23-28 Settembre 1996
36. A.Musumarra, G.Cardella, A.Di Pietro, S.L.Li, M.Papa, G.Pappalardo, F.Rizzo,
S.Tudisco, J.P.S. Van Schagen,
NIM A 370, 558 (1996).
37. G.Cardella, F.Amorini, M.Cabibbo, A.Di Pietro, G.Fallica, G.Franzó, P.Figuera,
S.Li, A.Musumarra, M.Papa, G.Pappalardo, G.Percolla, F.Priolo, V.Privitera, F.Rizzo,
S.Tudisco,
NIM A 378, 262 (1996).
38. M.La Commara, A.De Rosa, A.D’Onofrio, G.Inglima, A.Ordine, D.Pierroutsakou,
V.Roca, M.Romano, M.Romoli, M.Sandoli, G.Cardella, M.Papa, G.Pappalardo,
F.Rizzo, N.Alamanos, F.Auger, A.Gillibert, J.Gomex del Campo, D.Shapira,
Proceedings of XXXIV International Winter Meeting on Nuclear Physics, edited by
I.Iori. Bormio, Italy, January 22-28, 1996,p.394.
39. F.Rizzo, A.Amorini, M.Cabibbo, G.Cardella, A.Di Pietro, P.Figuera, A.Musumarra,
M.Papa, G.Pappalardo, S.Tudisco,
Proceedings of The International Symposium on Large-Scale Collective Motion of
Atomic Nuclei, Brolo, Italy, October 15-18, 1996.
40. ”Fusion Process and Elastic Scattering for the p+12C System at Energy Below
the Coulomb Barrier”,Proc.Int.Symposium on ”Large-Scale Collective Motion of
Atomic Nuclei”,Brolo 1996,Italy (Oral Presentation).
41. ”Fusion Process and Elastic Scattering at Low Energy for the p+12C System”,Proc.Fourth
Int.Conference on ”Nuclei in the Cosmos”,Notre Dame 1996,Indiana,USA (Poster
Presentation)
42. S.Pirrone, S.Aiello, N.Arena, Seb.Cavallaro, S.Femino’, G.Lanzalone, G.Politi, F.Porto,
S.Romano and S.Sambataro:
Complete and incomplete fusion in the reaction 35 Cl+12 C at the energy range70-154
MEV,
Phys. Rev. C (1996)
43. A.Brondi, M.Kildir, G.La Rana, R.Moro, E.Vardaci, S.Pirrone, F.Porto, S.Sambataro,
G.Politi, P.Figuera:
Reaction mechanism coexistence in the 123 MeV
, Phys. Rev. C54 (OCT-1996).
75
19
F +56 F e reaction
44. G. Ciavola, R. Alba, L. Calabretta, G. Cuttone, G. Di Bartolo, S. Gammino,
E. Migneco, G. Raia, D. Rifuggiato, A. Rovelli, J. Sura, D. Vinciguerra, H. Wollnik.
The EXCYT RIB facility at LNS
NIM 382 186 1996.
45. L. Calabretta, G. Ciavola, G. Cuttone, S. Gammino, P. Gmaj, E. Migneco, G. Raia,
D. Rifuggiato, A. Rovelli, J. Sura, V. Scuderi, E. Acerbi, F. Alessandria, G. Bellomo,
A. Bosatti, C. De Martinis, D. Giove, P. Michelato, C. Pagani, L. Rossi.
First operations of the LNS heavy ions facility
NIM 382 140 1996.
46. T. Suomijarvi, Y. Blumenfeld, P. Piattelli, J.H. Le Faou, C. Agodi, N. Alamanos,
R. Alba, F. Auger, G. Bellia, Ph. Chomaz, R. Coniglione, A. Del Zoppo, P. Finocchiaro, N. Frascaria, J.J. Gaardhoje, J.P. Garron, A. Gillibert, M. Lamehi-Rachti,
R. Liguori Neto, C. Maiolino, E. Migneco, G. Russo, J.C. Roynette, D. Santonocito,
P. Sapienza, J.A. Scarpaci, A. Smerzi.
Giant dipole resonance in very hot nuclei of mass A∼115
PRC 53 2258 1996
47. P. Piattelli, Y. Blumenfeld, J.H. Le Faou, T. Suomijarvi, C. Agodi, N. Alamanos,
R. Alba, F. Auger, G. Bellia, Ph. Chomaz, R. Coniglione, A. Del Zoppo, P. Finocchiaro, N. Frascaria, J.J. Gaardhoje, J.P. Garron, A. Gillibert, M. Lamehi-Rachti,
R. Liguori Neto, K. Loukachine, C. Maiolino, E. Migneco, J.C. Roynette, D. Santonocito, P. Sapienza, J.A. Scarpaci.
Limiting temperatures for collective motion: the giant dipole resonance in very hot
nuclei
PRC 53 2258 1996
48. G. Bellia, P. Finocchiaro, K. Loukachine, C. Agodi, R. Alba, L. Calabretta, R. Coniglione,
A. Del Zoppo, C. Maiolino, E. Migneco, P. Piattelli, G. Raciti, D. Rifuggiato,
D. Santonocito, P. Sapienza
MACISTE: The forward spectrometer for heavy ions at LNS-Catania
IEEE Transactions on nuclear science 43 (1996) 1737.
49. A. Del Zoppo, R. Alba, C. Agodi, R. Coniglione, C. Maiolino, E. Migneco, P.
Finocchiaro, K. Loukachine, P. Piattelli, D. Santonocito, P. Sapienza.
First order liquid-to-gas phase transitions in nuclear multifragmentation at the Fermi
energy?
Proceedings of CRIS ’96. First Catania Relativist Ion Studies. Acicastello, 27-31
Maggio 1996.
50. P. Sapienza, R. Coniglione, E. Migneco, C. Agodi, R. Alba, G. Bellia, A. Del Zoppo,
P. Finocchiaro, K. Loukachine, C. Maiolino, P. Piattelli, D. Santonocito.
Probing the pre-equilibrium stage in heavy ion collisions with hard photons and energetic protons
INTERNATIONAL SYMPOSIUM - Large-Scale Collective Motion of Atomic Nuclei. B rolo, 15-19 Ottobre 1996.
76
51. A. Del Zoppo, C. Agodi, R. Alba, R. Coniglione, C. Maiolino, E. Migneco, P. Sapienza,
G. Bellia, P. Finocchiaro, K. Loukachine, P. Piattelli, D. Santonocito.
4π Experiments with MEDEA International workshop on physics with 4π detectors
at low intermediate and relativistic energy. Romania 1996.
77
Chapter 17
Publications in THEORETICAL
PHYSICS 1996
52. A.Bonasera ”Turbulence and Self Similarity In Finite Systems”, Nuovo Cim. A109(1996)1405.
53. A. Badala, R.Barbera, A.Bonasera, A.Palmeri, G.S.Pappalardo, F.Riggi, A.C.Russo,
G.Russo, R.Turrisi
”Search for ∆(1232)-resonance excitation in heavy-ion collisions around 100 MeV/nucleon.”
Phys. Rev. C 54 (1996) 2138.
54. A. Badala, R.Barbera, A.Bonasera, A.Palmeri, G.S.Pappalardo, F.Riggi, A.C.Russo,
G.Russo, R.Turrisi
”Evidence of ∆(1232)-resonance excitation in subthreshold pion production at intermediate energies”,
12th Winter Workshop on Nuclear Dynamics, Snowbird (USA), (1996).
55. P.Finocchiaro, M.Belkacem, T.Kubo, V.Latora and A.Bonasera
”Second Order Phase Transition: From Infinite To Finite Systems”,
Nucl.Phys. A600(1996)236.
56. M.Petrovici, A.Andronic, I.Berceanu, A.Buta, M.Duma, D.Moisa, A.Pop, V.Simion,
A.Bonasera, G.Imme, G.Lanzano, G.Raciti, N.Colonna, G.d’Erasmo, A.Pantaleo
” Dissipative Process in 19F+27Al at 5.9 MeV/A,
Zeit. Phys. A354(1996)11.
57. M.Belkacem,P.F.Mastinu, V.Latora, A.Bonasera, M.D’Agostino, M.Bruno, J.D.Dinius,
M.L.Fiandri, F.Gramegna, D.O.Handzy, W.C.Hsi, W.Huang, G.V.Margagliotti, P.M.Milazzo,
C.P. Montoya, G.F.Peaslee, R.Rui, C.Schwarz, G.Vannini, C.Williams
”Searching for the Nuclear Liquid-Gas Phase Transition in Au+Au Collisions at 35
MeV/nucleon”,
Phys.Rev.C54(1996)2435.
78
58. P.F.Mastinu, M.Belkacem, Multics-Miniball coll., V.Latora and A.Bonasera ”Circumstantial Evidence For Critical Behavior
In Peripheral Au+Au Collisions at 35 MeV/Nucleon”,
Phys.Rev.Lett. 76(1996) 2646.
59. K.Morawetz and M.DiToro
”The contribution of density fluctuations to the damping of Giant Resonances”
Phys.Rev. C54 (1996) 833
60. M.Colonna, M.DiToro and A.Guarnera
”Crisis of the mean field picture in nuclear dynamics”
in ”Perspectives in Nuclear Theory”, ed.s A.Fabrocini and S.Rosati, Pisa 1996,
pp.293-302
61. J.Y.Liu, S.J.Wang, M.DiToro, H.Liu, X.G.Lee and W.Zuo
”Two body correlation transport theory for heavy ion collisions”
Nucl.Phys. A604 (1996) 341
62. M.Colonna, M.DiToro, S.Maccarone, M.Zielinska Pfabe’ and A.Guarnera
”Reaction mechanisms in medium energy collisions: influence of dynamical fluctuations”
In ”Relativistic Ion Studies: Critical Phenomena and Collective Observables”, Ed.s
S.Costa, S.Albergo, A.Insolia and C.Tuve’, World Sci. 1996 pp.369-378
63. A.Guarnera, M.Colonna and Ph.Chomaz,
”3D stochastic mean-field simulations of the spinodal fragmentation of dilute nuclei”,
Phys.Letters B 373 (1996) 267
64. B.Jacquot, A.Guarnera, M.Colonna and Ph.Chomaz,
”Validity of stochastic mean field simulations of classical liquid-gas decomposition”,
Phys.Letters B (1996) July
65. S.Ayik, Ph.Chomaz, M.Colonna, J.Randrup,
”Analysis of Boltzmann-Langevin dynamics in nuclear matter”,
Z.Phys. A 335 (1996) 407
66. M.Cinausero et al.,
”Entrance channel mass asymmetry and the decay of hot nuclei”,
Phys.Lett. B 383(1996) 372
67. B.Jacquot, S.Ayik, Ph.Chomaz, M.Colonna,
”Fluid Dynamical Approach to spinodal instabilities in finite nuclear systems”,
Phys. Lett.B 383(1996) 247
79
68. C. Volpe, Ph. Chomaz, M. V. Andrés, F. Catara, E.G. Lanza,
Are Giant Resonances Harmonic Vibrations ?,
Nulc. Phys. A599, 347c (1996)
69. Ph. Chomaz, C. Volpe, M. V. Andrés, F. Catara, E.G. Lanza,
Non-linear vibrations in stable and exotic nuclei,
Proc. of International Workshop on Physics of Unstable Nuclear Beams, 28-31
August 1996, Serra Negra (SP), Brazil
70. A. Atalmi, M. Baldo, G.F. Burgio and A. Rapisarda,
”Chaos vs. linear instability: a fractal analysis characterization”,
Phys. Rev. C 53 (1996) 2566.
71. A. Atalmi, M. Baldo, G.F. Burgio and A. Rapisarda, proceedings of th e XXXIV,
” Dynamical chaos and critical behavior in Vlasov simulations of nuclear multifragmentation”,
International winter meeting on Nuclear Physics, Bormio (Italy), Ed. I. Iori, (1996)
p.79.
72. G.F. Burgio, M. Baldo, A. Rapisarda and P. Schuck,
” Chaoticity and dissipation of nuclera collective motion in a classical model ”
proceedings of the XXXIV International winter meeting on Nuclear Physics, Bormio
(Italy), Ed. I. Iori, (1996) p.375
73. A. Atalmi, M. Baldo, G.F. Burgio and A. Rapisarda,
” Universal features in the nuclear multifragmentation phase transition”,
Proceedings of the 1st CRIS international conference, Acicastello (Italy), Eds. S.
Costa, S. Albergo, A. Insolia and C. Tuvé, World Scientific (1 996) p.56.
74. M. Belkacem, A. Bonasera, V. Latora and A. Rapisarda,
” Instabilities in finite systems”,
Proceedings of the 1st CRIS international conference, Acicastello (Italy), Eds. S.
Costa, S. Albergo, A. Insolia and C. Tuvé, World Scientific (1 996) p.151
75. H. Morita, H. Nakai, P. Tomasello, H. Nakatsuji:
”Theoretical Study of the ionized Electronic Structure of the Octahedral Complex
MoF6”
Bull. Chem.-Phys. Soc. Jpn vol. 69 1893-1899 (1996)
76. H. Nakai, H. Morita, P. Tomasello and H. Nakatsuji:
” Electronic Structures of MoF6 and MoOF4 in the Ground and Excited States: A
SAC-CI and Frozen Orbital Analysis Study,
in publication on Inorganic Chemistry
80
77. G.G.N.Angilella, R.Pucci, F.Siringo.
On the dependence of the critical temperature on pressure in the bipolaron model of
high Tc superconductors
in ”High Pressure Science & Technology”, W. Trzeciakowski Editor, World Scientific, Singapore (Gennaio,1996)
78. F.Siringo.
On the conductivity of topologically disordered systems.
Journal of Physics: Condensed Matter 8, 1169 (1996).
79. F.Siringo, R.Pucci, G.G.N.Angilella. Are light alkali metals still metals under high
pressure?
High Pressure Research, in press.
80. F.Siringo.
Low Dimensional Ordering on a Lattice Model.
Physics Letters A, in press.
81. A. Scalia,
”Astrophysical S(E)-Factor at Very Low Energy :Screening Effect or Nuclear Effect?”,
Proc.Fourth Int.Conference on ”Nuclei in the Cosmos”,Notre Dame 1996,Indiana,USA
(Oral Presentation).
82. A. Scalia,
”Astrophysical S(E)- Factor Below the Coulomb Barrier at Very Low Energy :Screening Effect or Nuclear effect?”,
Proc.Int.Symposium on ”Large-Scale Collective Motion of Atomic Nuclei”,Brolo
1996, Italy (Poster Presentation).
83. Fabio Siringo, Giuseppe G.N. Angilella, and Renato Pucci,
Renormalization-group approach to anisotropic superconductors at finite temperature,
Phys. Rev. B 53, 2870 (1996).
84. Giuseppe G.N. Angilella, Renato Pucci, and Fabio Siringo,
Interplay among critical temperature, hole content, and pressure in the cuprate supercondutors,
Phys. Rev. B 54, 15471 (1996).
85. Fabio Siringo, Giuseppe G.N. Angilella, and Renato Pucci,
Renormalization-group analysis of the superconductive instability in anisotropic systems,
Proceedings of the XXI International Conference on Low Temperature Physics,
Prague, Czech Rep., August 8-14, 1996 [Czechoslovak Journal of Physics, 46 (Suppl.
S2), 957 (1996)].
81
86. Giuseppe G.N. Angilella, Renato Pucci, Fabio Siringo,
On the dependence of the critical temperature on pressure in the bipolaron model of
high Tc superconductors,
in High Pressure Science, proceedings of the Joint XV AIRAPT & XXXIII EHPRG International Conference, Warsaw, Poland, Sept. 11-15, 1995, edited by W.
Trzeciakowski, p. 685 (World Scientific, Singapore, 1996).
87. Fabio Siringo, Renato Pucci, and Giuseppe G.N. Angilella,
Are light alkali metals still metals under high pressure?,
Abstracts of the XV EPS General Conference of the Condensed Matter Division,
Baveno-Stresa, Italy, April 22-25, 1996, edited by L.C. Andreani, G. Chiarotti, G.
Guizzetti, M. Patrini, A. Stella [ECA 20A, 190 (1996)].
88. Fabio Siringo, Renato Pucci, Giuseppe G.N. Angilella,
Is there an Intermediate Ionic Phase in Hydrogen under high pressure?,
Gordon Conference on Research at High Pressure, June 23, 1996, Meriden, N.H.
89. Giuseppe G.N. Angilella, Renato Pucci, and Fabio Siringo,
Interplay among critical temperature, hole content, and pressure in the cuprate supercondutors,
poster presentation at the Scuola Nazionale di Fisica della Materia, Villa Gualino,
Torino, September 8–20, 1996.
90. A. La Magna and R. Pucci,
Variational study of the discrete Holstein model,
Phys. Rev. B 53, 8449 (1996).
91. A. Grassi, G.M. Lombardo, N.H. March, and R. Pucci,
Correlation energies in polyatomic molecules modelled in terms of bond orders,
Mol. Physics, 87, 553 (1996).
92. P.M.Santini:
The Method of the Multiple-Scales and the Nonlinear Schrödinger Hierarchy”,
Proceedings of the 1st Workshop ”Nonlinear Physics, Theory and Experiments”,
Gallipoli (Lecce); edited by E.Alfinito, M.Boiti, L.Martina and F.Pempinelli, World
Scientific, 1996.
93. P.M.Santini:
”Multiscale expansions, symmetries and the nonlinear Schrödinger hierarchy”,
in “Algebraic Aspects of Integrable Systems, In Memory of Irene Dorfman”, edited
by A.S.Fokas and I.M.Gelfand, Vol. 26, Birkhauser (Boston), 1996.
94. P.M.Santini:
”Linear Theories, Hidden variables and Integrable Nonlinear Equations”;
Phys. Lett. 212A, 43 (1996).
82
95. A.Doliwa and P.M.Santini:
”The integrable dynamics of discrete curves”,
in: ”Symmetries and Integrability of Difference Equations”; eds. D. Levi, L. Vinet
and P. Winternitz, CRM Proceedings and Lecture Notes, Vol. 9, AMS Providence,
1996.
96. F. Catara, G. Piccitto, M. Sambataro e N. Van Giai,
Torwards a self-consistent Random Phase Approximation for Fermi systems,
Phys. Rev. B54 17536, 1996
97. E. Kwasniewicz, F. Catara e M. Sambataro,
Study of the low-lying states of 1s0d- and 1p0f-shell nuclei in the Collective Pair
Approximation,
New perspectives in nuclear structures, 207, 1996
98. E. Kwasniewicz, F. Catara e M. Sambataro,
83
Chapter 18
Publications in SOLID STATE
PHYSICS 1996
99. G.Burrafato, S.O.Troja, E.Turrisi, L.Arcidiacono, C.Caputa, A.Cro, G.Grasso, A.M.Gueli,
M.Russo
Application of thermoluminescence to determine the presence of precursor oxides in
high Tc ceramic superconductors
NUCL. INSTR.AND METHOD IN PHIS. RES. B116, (1996), 531
100. G. Faraci, F. Gozzo, S. La Rosa, A. R. Pennisi, G. Margaritondo:
” Cs bonding at the Cs/GaAs(110) interface ”
Phys. Rev. B 53, 3987, 1996.
101. G. Faraci, A. R. Pennisi, G. Margaritondo:
” Catalytic oxidation of the GaAs(110) surface promoted by a Cs overlayer ”
Phys. Rev. B 53, 13851, 1996.
102. G. Faraci, A. R. Pennisi, Y. Hwu:
” Anomalous branching ratio of the Cs 4d doublet in submonolayer depositions”
Phys. Rev. B 54, 4515, 1996.
103. G. Faraci, S. La Rosa, A. R. Pennisi:
” Cs/GaAs(110) interface: bonds, catalytic oxidation and anomalous branching ratio”
Boll. VI Congr. Sez. A INFM, Perugia 23-26 ott.1996, pag.1
104. G. Faraci, A. R. Pennisi:
”XANES of overpressurized Kr clusters in Si and Be”
Boll. Convegno SILS Roma 25-27 giugno 1996 pag.39
105. G. Faraci:
”Recent study of Cs/Ge(100) interface at Elettra”
84
Invited talk, IV Elettra Users’ Meeting 2-3 dicembre 1996.
106. K. Kyllesbech Larsen, V. Privitera, S. Coffa, F. Priolo, S.U. Campisano, A. Carnera
Trap-Limited Migration of Si Self-Interstitials at Room Temperature;
Phys. Rev. Lett. 76, 1493 (1996)
107. C. Spinella, S. Lombardo, F. Priolo, S.U. Campisano
Mechanism and Kinetics of Ion-Assisted Nucleation in Amorphous Silicon;
Phys. Rev. B, 53, 7742 (1996)
108. K. Kyllesbech Larsen, V. Privitera, S. Coffa, F. Priolo, C. Spinella, M. Saggio, S.U.
Campisano
The Damage Recovery and Electrical Activation of Shallow Boron Implants in Silicon: The Effects of High Energy Implants;
109. F. Priolo, G. Franzó, S. Coffa, A. Polman, E. Snoeks, G.N. van den Hoven, S.
Libertino, S. Lombardo, S.U. Campisano, A. Carnera
Optical Doping of Materials by Erbium Ion Implantation;
110. S. Coffa, S. Lombardo, F. Priolo, G. Franzó, S.U. Campisano, A. Polman, G.N. van
den Hoven
Erbium Doping of Crystalline and Amorphous Silicon for Optoelectronic Applications;
Il Nuovo Cimento, 18 1 (1996)
111. V. Privitera, S. Coffa, F. Priolo, K. Kyllesbech Larsen, G. Mannino
Room Temperature Migration and Interaction of Ion Beam Generated Defects in
Crystalline Silicon;
Appl. Phys. Lett. 68, 3422 (1996)
112. S. Coffa, G. Franzó, F. Priolo
High Efficiency and Fast Modulation in Er-Doped Si Diodes
Appl. Phys. Lett. 69, 2077 (1996)
113. V. Privitera, S. Coffa, F. Priolo, K. Kyllesbech Larsen, S. Libertino
Room Temperature Migration of Ion Beam Injected Point Defects in Crystalline
Silicon;
Nucl. Instrum. Meth. B, 120, 9 (1996)
114. S. Coffa, G. Franzó, F. Priolo, S. Libertino, R. Mosca, E. Gombia, C. Spinella
Ion Implantation Doping of Si for Optoelectronic Applications; Nucl. Instrum.
Meth. B, 120, 74 (1996)
85
115. C. Spinella, F. Priolo, S. Lombardo, R.A. Puglisi, S.U. Campisano
Nuclear Energy and Cascade Effects on the Ion-Assisted Nucleation of Amorphous
Silicon;
Nucl. Instrum. Meth. B, 120, 198 (1996)
116. D. Carey, J.F. Donegan, R.C. Barklie, F. Priolo, G. Franzó, S. Coffa
Electron Paramagnetic Resonance of Er-Doped Silicon;
Appl. Phys. Lett., 69, 3854 (1996)
117. C. Spinella, S. Lombardo, F. Priolo, S.U. Campisano
it Ion-Assisted Nucleation in Amorphous Silicon: Mechanism and Theoretical Description;
in Thermodynamics and Kinetics of Phase Transformations, edited by J.S. Im, A.L.
Greer, B. Park, G.B. Stephenson (Materials Research Society, Pittsburgh, USA,
1996)
118. F. Priolo, S. Coffa, G. Franzó, A. Polman
Excitation Mechanisms and Light Emitting Device Performances in Er-Doped Crystalline Si;
in Rare-Earth Doped Semiconductors II, edited by S. Coffa, A. Polman, R. Schwartz
(Materials Research Society, Pittsburgh, USA, 1996)
119. S. Coffa, G. Franzó, F. Priolo
Materials and Devices for Si-based Optoelectronics;
in ESSDERC’96 - Proceedings of the 26th European Solid State Device Research
Conference, edited by G. Baccarani and M. Rudan Editions Frontieres, 1996) p.739
86
Chapter 19
Publications in GENERAL
PHYSICS 1996
120. V. Latora, A. Rapisarda and S. Vinciguerra,
” Microseismicity affecting the time clustering properties of the low eastern flank of
Mt. Etna between 1989 anr 1994”,
Proceedings of the International conference ”Etna fifteen years on”, Cheltenham
(U.K .), eds. P.J. Gravestock and W.J. McGuire, (1996), p.34.
87
Chapter 20
Publications in APPLIED PHYSICS
1997
1. S. Coffa, V. Privitera, F. Priolo, S. Libertino, G. Mannino
Depth Profiles of Vacancy- and Insterstitial-Type Defects in MeV Implanted Si;
J. Appl. Phys. 81, 1639 (1997)
2. A. Nylandsted Larsen, C. O’Raifeartaigh, R.C. Barklie, B. Holm, F. Priolo, G.
Franzó, G. Lulli, M. Bianconi, R. Nipoti, J.K.N. Lindner, A. Mesli, J.J. Grob, F.
Cristiano, P.L.F. Hemment
MeV Implantation Induced Damage in Relaxed Si1−x Gex ;
J. Appl. Phys. 81, 2208 (1997)
3. C. Frigeri, A. Carnera, B. Fraboni, A. Gasparotto, A. Cassa, F. Priolo, A. Camporese, G. Rossetto
Defect Characterization in InP Substrates Implanted with 2 MeV Fe Ions;
Mater. Sci. and Eng. B 44, 193 (1997)
4. V. Privitera, F. Priolo, G. Mannino, S.U. Campisano, A. Carnera, G. Arena, C.
Spinella
The Effect of Reactive Plasma Etching on the Transient Enhanced Diffusion of
Boron in Silicon;
Appl. Phys. Lett. 71, 1834 (1997)
5. F. Priolo, V. Privitera, S. Coffa, S. Libertino
Ion Beam Injected Point Defects in Crystalline Silicon: Migration, Interaction and
Trapping Phenomena;
in Materials Modification and Synthesis by Ion Beam Processing, edited by D.E.
Alexander, N.W. Cheung, B. Park, W. Skorupa (Materials Research Society, Pittsburgh, USA, 1997) Mat. Res. Soc. Symp. Proc. 438, 53 (1997)
6. S. Libertino, S. Coffa, V. Privitera, F. Priolo
The Effect of Impurity Content and Ion Mass on the Depth Profiles of Vacancy-Type
Defects in MeV Implanted Si;
88
in Materials Modification and Synthesis by Ion Beam Processing, edited by D.E.
Alexander, N.W. Cheung, B. Park, W. Skorupa (Materials Research Society, Pittsburgh, USA, 1997) Mat. Res. Soc. Symp. Proc. 438, 65 (1997)
7. V. Privitera, S. Coffa, K. Kyllesbech Larsen, S. Libertino, G. Mannino, F. Priolo
Point Defects Migration and Agglomeration in Si at Room Temperature: the Role
of Surface and Impurity Content;
in Defects and Diffusion in Silicon Processing, edited by S. Coffa, T. Diaz de la
Rubia, P. A. Stolk, C.S. Rafferty (Materials Research Society, Pittsburgh, USA,
1997) Mat. Res. Soc. Symp. Proc. 469, (1997)
8. C. Frigeri, A. Carnera, B. Fraboni, A. Gasparotto, F. Priolo, A. Camporese, G.
Rossetto
Distribution of Fe and extended defects in Fe-implanted InP;
in Proceedings of Microscopy of Semiconducting Materials - 1997, A.G. Cullis, J.L.
Hutchison editors, (IOP Publishing Ltd, 1997) p.523
9. R.C. Barklie, C. O’Raifeartaigh, A. Nylandsted Larsen, F. Priolo, G. Lulli, J.J.
Grob, A. Mesli, J.K.N. Lindner, F. Cristiano, P.L.F. Hemment
Ion Implantation Induced Damage in Relaxed Si1−x Gex ;
in Proceedings of the 11th International Conference on Ion Implantation Technology,
Emi Ishidida et al. Editors, IEEE (1997) p.698
10. F. Cristiano, C. Bonafos, A. Nejim, S. Lombardo, M. Omray, D. Alquier, A. Martinez, S. U. Campisano, P. L. F. Hemment, and A. Claverie,
”Interstitial trapping efficiency of C implanted into pre-amorphized Si, Control of
EOR defects”,
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39. A. Badalà, R. Barbera, A. Bonasera, M. Gulino, A. Mascali, A. Palmeri, G.S.Pappalardo,
F. Riggi, A. C. Russo, G. Russo, R. Turrisi, V. Dunin, C. Ekstrom, G. Ericsson,
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40. S.Pirrone, S.Aiello, N.Arena, Seb. Cavallaro, S.Femino’, G.Lanzalone, G.Politi,
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R.Potenza, G.V.Russo, A.Soutoul, O.Testard, C.E.Tull, C.Tuvè, C.J.Waddington,
W.R.Webber, J.P.Wefel (The Transport Collaboration)
Relativistic Interaction of 22 Ne and 26 Mg in Hydrogen and the Cosmic Ray Implications
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49. C.N.Knott, S.Albergo, Z.Caccia, C.-X.Chen, S.Costa, H.J.Crawford, M.Cronqvist,
J.Engelage, L.Greiner, T.G.Guzik, A.Insolia, P.J.Lindstrom, J.W.Mitchell, R.Potenza,
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Interactions of Relativistic 36 Ar and 40 Ar Nuclei in Hydrogen: Isotopic Production
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50. C.Tuvé, S.Albergo, D. Boemi, Z.Caccia, C.X.Chen, S.Costa, H.J.Crawford, M.Cronqvist,
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Neutron Production at 0o from the 40 Ca + H Reaction at Elab = 357 and 565
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51. C.-X.Chen, S.Albergo, Z.Caccia, S.Costa, H.J.Crawford, M.Cronqvist, J.Engelage,
L.Greiner, T.G.Guzik, A.Insolia, C.N.Knott, P.J.Lindstrom, M.McMahon, J.W.Mitchell,
R.Potenza, G.V.Russo, A.Soutoul, O.Testard, C.E.Tull, C.Tuvé, C.J.Waddington,
W.R.Webber and J.P.Wefel (The Transport Collaboration)
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O.Testard, C.E.Tull, C.Tuvé, C.J.Waddington, W.R.Webber and J.P.Wefel (The
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A Heavy Ion Spectrometer System for the Measurement of Projectile Fragmentation
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53. J.A.Hauger P. Warren, S.Albergo, F.Bieser, F.P.Brady, Z. Caccia, D.A.Cebra, A.D.Chacon,
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M.Justice, D.Keane, J.C.Kintner, V.Lindenstruth, M.A.Lisa, H.S.Matis, M.McMahan,
C.McParland, W.F.J.Müller, D.L.Olson, M.D.Partlan, N.T.Porile, R.Potenza, G.Rai,
J.Rasmussen, H.G.Ritter, J.Romanski, J.L.Romero, G.V.Russo, H.Sann, R.P.Scharenberg,
A.Scott, Y.Shao, B.K.Srivastava, T.J.M.Symons, M.Tincknell, C.Tuvé, S.Wang,
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Multifragmentation of the Remnant Produced in the Reaction of 1A GeV Gold with
Carbon
94
54. J.Lauret, S.Albergo, F.Bieser, N.N.Ajitanand, John M.Alexander, F.P.Brady, Z.Caccia,
D.Cebra, A.D.Chacon, J.L.Chance, Y.Choi, P.Chung, S.Costa, P.Danielewicz, J.B.Elliott,
M.Gilkes, J.A.Hauger, A.S.Hirsch, E.L.Hjort, A.Insolia, M.Justice, D.Keane, J.Kintner,
Roy A.Lacey, V.Lindenstruth, M.A.Lisa, H.S.Matis, R.McGrath, M.McMahan, C.McParland,
W.J.F.Müller, D.L.Olson, M D.Partlan, N.T.Porile, R.Potenza, G.Rai, J.Rasmussen,
H.G.Ritter, J.Romanski, J.L.Romero, G.V.Russo, H.Sann, R.Scharenberg, A.Scott,
Y.Shao, B.K.Srivastava, T.J.M.Symons, M.Tincknell, C.Tuvé, S.Wang, P.Warren,
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S.Costa, J.B.Elliott, M.Gilkes, J.A.Hauger, A.S.Hirsch, E.L.Hjort, A.Insolia, M.Justice,
D.Keane, J.C.Kintner, M.A.Lisa, H.S.Matis, M.McMahan, C.McParland, D.L.Olson,
M.D.Partlan, N.T.Porile, R.Potenza, G.Rai, J.Rasmussen, H.G.Ritter, J.Romanski,
J.L.Romero, G.V.Russo, R.Scharenberg, A.Scott, Y.Shao, B.Srivastava, T.J.M.Symons,
M.Tincknell, C.Tuvé, S.Wang, P.Warren, H.H.Wieman, K.Wolf (EOS Collaboration)
The Energy Dependence of Flow in Ni Induced Collisions from 400A to 1970A MeV
56. J.C.Kintner, S.Albergo, F.Bieser, F.P.Brady, Z.Caccia, D.Cebra, A.D.Chacon, J.L.Chance,
Y.Choi, S.Costa, J.B.Elliott, M.L.Gilkes, J.A.Hauger, A.S.Hirsch, E.L.Hjort, A.Insolia,
M.Justice, D.Keane, M.A.Lisa, H.S.Matis, M.McMahan, C.McParland, D.L.Olson,
J.L.Romero, G.V.Russo, R.Scharenberg, A.Scott, Y.Shao, B.Srivastava, T.J.M.Symons,
M.Tincknell, C.Tuvé, S.Wang, P.Warren, H.H.Wieman, T.Wienold, K.Wolf (EOS
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Pion Flow and Anti-Flow in 1.15 A GeV Au + Au
57. E.L.Hjort, S.Albergo, F.Bieser, F.P.Brady, Z.Caccia, D.A.Cebra, A.D.Chacon, J.L.Chance,
Y.Choi, S.Costa, J.B.Elliott, M.L.Gilkes, J.A.Hauger, A.S.Hirsch, A.Insolia, M.Justice,
D.Keane, J.C.Kintner, M.A.Lisa, H.S.Matis, M.McMahan, C.McParland, D.L.Olson,
J.L.Romero, G.V.Russo, R.P.Scharenberg, A.Scott, Y.Shao, B.K.Srivastava, T.J.M.Symons,
M.Tincknell, C.Tuvé, S.Wang, P.G.Warren, H.H.Wieman, T.Wienold, and K.Wolf
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∆ Resonance Production in 58 Ni + Cu Collisions at E=1.97 A GeV
58. Morton Kaplan for the E896 Collaboration
Search for a Short-Lived Dibaryon in Au + Au Collisions: Status of AGS Experiment 896
13th Winter Workshop on Nuclear Dynamics
Marathon, Florida, USA, 1 - 8 February 1997
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J.Engelage, L.Greiner, T.G.Guzik, A.Insolia, C.N.Knott, P.J.Lindstrom, J.W.Mitchell,
95
Neutron Production at 0o from 40 Ca + H at Elab = 357 and 565 A MeV
6th International Conference on Nucleus Nucleus Collisions
Gatlinburg, Tennessee, USA, June 2-6, 1997
Contributed Papers, pag. P-005
J.Engelage, L.Greiner, T.G.Guzik, A.Insolia, C.N.Knott, P.J.Lindstrom, J.W.Mitchell,
Neutron Production at 0o from 40 Ca + H at Elab = 357 and 565 A MeV
25th International Cosmic Ray Conference
Durban, South Africa, 30 July - 6 August 1997
Contributed Papers, Volume 4, pag. 313
61. the Transport Collaboration
The Systematics of Isotopic Production Cross Sections and Implications for Cosmic
Ray Astrophysics
Isotopic Production Cross Sections of Relativistic
40
Ca in Hydrogen
Isotope Production in Hydrogen by Relativistic 36 Ar and
40
Ar Nuclei
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G.Cardella, M.Papa, G.Pappalardo, F.Rizzo, N.Alamanos, F.Auger, A.Gilibert.
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A.Ordine, D.Pierroutsakou, V.Roca, M.Romano, M.Romoli, F.Terrasi, M.Trotta,
G.Cardella, M.Papa, G.Pappalardo, F.Rizzo, N.Alamanos, F.Auger, A.Gilibert.
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68. M.Romoli, A.Boiano, L.Campaiola, A.De Rosa, A.D’Onofrio, G.Inglima, M.La Commara, A.Ordine, D.Pierroutsakou, V.Roca, M.Sandoli, F.Rizzo, F.Amorini, S.Tudisco.
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70. M.Papa, F.Amorini, M.Cabibbo, G.Cardella, A.Di Pietro, P.Figuera, A.Musumarra,
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- Nuclear Physics A622, 226-238, (1997).
77. B. Jakobsson, M.Berg, L.Carlen, A. Fokin, R. Ghetti, J. Martensson, B. Noren, A.
Oskarsson, H.J. Whitlow, C. Ekstrom, G. Ericsson, J. Romanski, E.J. van Veldhuizen, L. Westerberg, J, Julien, O. Skeppstedt, K. Nybo, T.F. Thorsteinsen, S.
Amirelmi, M. Guttormsen, G. Lovhoiden, V. Bellini, F. Palazzolo, M.L. Sperduto,
J.P. Bondorf, I. Mishustin, V. Avdeichikov, O.V. Lozhkin, Yu. Murin:
GROSS AND FINE STRUCTURE OF PION PRODUCTION EXCITATION FUNCTIONS IN p-NUCLEUS AND NUCLEUS-NUCLEUS REACTIONS”
- Phys. Rev. Lett., 78 (1997) 3828
98
Chapter 22
Publications in THEORETICAL
PHYSICS 1997
78. A. Bonanno, J. Polonyi e D. Zappalà:
”Renormalization group analysis of the heavy field decoupling in a scalar theory”,
in Proceedings of Quark Confinement and Hadron Spectrum II, Como, Italy, June
1996, Eds. N. Brambilla and G. Prosperi, World Scientific (1997), pg. 250.
79. A.Bonanno e D. Zappalà,
”Nonperturbative renormalization Group approach for a scalar theory in higherderivative gravity”,
Phys. Rev. D 55 (1997), 6135.
80. A.Bonanno e D. Zappalà,
”Fixed point analysis of a scalar theory with external field”,
Phys. Rev. D 56 (1997) 3759.
81. A.Sedrakian, T.Alm, U.Lombardo
Superfluidity in Asymmetric Nuclear Matter
Phys.Rev. C55 (1997) R582.
82. H.J.Schulze, A. Schnell, G.Roepke and U.Lombardo
Nucleon-Nucleon cross sections in nuclear matter
Phys.Rev.C55 (1997)3006
83. H.J. Schulze and U. Lombardo
In-medium Nucleon Cross Sections from Bruckner Theory
Proc.of the XXXV Int. Winter Meeting on Nuclear Physics, Bormio 1997. Ed I.Iori,
Universita Milano 1997.
84. V.M.Kolomietz, A.B.Larionov and M.DiToro
”Collisionless damping of nuclear sound at finite temperature”
Nucl.Phys. A613 (1997) 1
99
85. V.Baran, M.Cabibbo, Y.Cai, M.Colonna, M.DiToro and A.Guarnera
”Mass and charge symmetry in fusion dynamics
Journal of Physics G: Nucl.Part.Phys. 23 (1997) 1341
86. V.Baran, A.Bonasera, M.Colonna, M.DiToro and A.Guarnera
”Giant resonances built on highly excited states: a test-ground for nuclear dynamics”
Prog.Part.Nucl.Phys. 38 (1997) 263
87. B.Jacquot,M.Colonna,S.Ayik,Ph.Chomaz,
Nucl.Phys. A617 (1997) 356.
88. M.Colonna, J.Cugnon, E.C. Pollacco,
Phys. Rev. C55 (1997) 1404.
89. J.Lukasik et al., M.Colonna et al.,
Phys. Rev. C55 (1997) 1906.
90. A.Guarnera, Ph.Chomaz, M.Colonna and J.Randrup,
Phys. Lett. B403 (1997) 191.
91. H.Q.Song, M.Baldo, G.Giansiracusa and U.Lombardo
Three hole-line contribution in nuclear matter revisited
Phys.Letters B411 (1997) 237.
92. A. Schnell, H.J.Schulze, G.Roepke and U.Lombardo
Elastic nucleon-nucleon scattering cross sections in nuclear matter
Phys.Rev.C57 (1998) 806.
93. H.J.Schulze,M.Baldo,U.Lombardo,J.Cugnon,A.Lejeune.
Hyperonic Nuclear Matter in Brueckner Theory
Phys.Rev. C57 (1998) 704.
94. A.Bonasera and A.Iwamoto:
Spontaneous Fission: A Kinetic Approach
PRL 78(1997)187.
95. A. Bonasera, V. Kondratiev and A. Iwamoto:
Nuclear Dynamics Below the Coulomb Barrier
Journ.Phys.G23(1997)1297.
96. A.Bonasera and A.Iwamoto:
Reply to the Comment on Spontaneous Fission: A Kinetic Approach by G.Bertsch
and A.Bulgac
PRL79(1997)3537.
100
97. V.Baran, M.Cabibbo, Y.Cai, M.Colonna, M.DiToro, A.Guarnera and T.I.Mikhailova
”Fusion-Fission dynamics: entrance channel effects and dissipation”
Proc. Large scale collective motion of atomic nuclei, Ed.G.Giardina et al., World.Sci.
1997, p.104-119
98. M.Colonna, M.DiToro, V.Baran, G.Fabbri, A.Larionov, S.Maccarone and H.Sagawa
”Isospin effects on nuclear dynamics”
Proc. ”Perspectives in Heavy Ion Physics” Ed.C.Signorini et al., Compositori
Bologna 1997
99. V.Baran, M.Colonna, M.DiToro, G.fabbri, A.B.Larionov, S.Maccarone and H.Sagawa,
”Charge asymmetry effects on reaction mechanisms”
Proc.VI International School Seminar on Heavy Ion Physics, Dubna Sett.97, Ed.
Y.Oganessian in press
100. M.DiToro, V.M.Kolomietz and A.B.Larionov
”Isovector vibrations in hot nuclear matter”
Proc.VI International School Seminar on Heavy Ion Physics, Dubna Sett.97, Ed.
Y.Oganessian in press
101. V.Baran, M.Cabibbo, Y.Cai, M.Colonna, M.DiToro, A.Guarnera and T.I.Mikhailova
”New results in Fusion-Fission dynamics:entrance channel effects and dissipation”
Proc. Nuclear data for science and technology Ed.G.Reffo et al., Compositori
Bologna 1997 in press
102. H.J. Schulze and U. Lombardo
In-medium Nucleon Cross Sections from Bruckner Theory
Proc.of the XXXV Int. Winter Meeting on Nuclear Physics, Bormio 1997. Ed I.Iori,
103. M. Baldo, U. Lombardo, P. Schuck and A. Sedrakian
Superfluidity in Nuclear Matter
Proceedings of the Workshop on ” Bose-Einstein Condensation” Pune december
1996. In press.
104. U. Lombardo
Crossover from a Superfluid Fermi System to a Bose Condensate as a Mechanism
for Deuteron Production in HIC.
Proc.of the XXXV Int.Winter Meeting on Nuclear Physics, Bormio 1997.Ed I.Iori,
105. A.Bonasera and J.Schulte
Scaling of Large Fluctuations In Finite Systems
Proc.of Tsukuba conf.on ”Similarities and Differences between Nuclei and Metallic
Clusters”, World Sci.(1997), in stampa.
101
106. A.Iwamoto, V. Kondratiev and A. Bonasera
Vlasov Treatment of Spontaneous Fission and Sub-barrier Fusion
Proc.of Tours meeting on Nuclear Physics, World Sci.(1997), in stampa.
107. A.Bonasera, M.Bruno and M.D’Agostino
”Searching for Critical Phenomena in Nuclear Dynamics”,
Snowbird (1998) in press.
108. U. Lombardo,P. Schuck and Z. Wei
Isospin Effects in Nuclear Binding Energy
Proc.of the XXXVI Int.Winter Meeting on Nuclear Physics, Bormio 1998.Ed I.Iori,
Universita’ Milano 1998.
109. M.DiToro, V.Baran, M.Colonna, G.Fabbri, A.Larionov, S.Maccarone and H.Sagawa
”Isospin effects on nuclear dynamics”
Proc.of the XXXVI Int.Winter Meeting on Nuclear Physics, Bormio 1998.Ed I.Iori,
Universita’ Milano 1998.
110. M. Sambataro e J. Suhonen,
QRPA and beta decay physics: higher-order approximations in a boson formalism
Phys. Rev C56(1997)782
111. E.G.Lanza, M.V.Andres, F.Catara, Ph.Chomaz, C.Volpe
Role of anharmonicities and non linearities in heavy ion collisions. A microscopic
approach,
Nucl.Phys. A613(1997)445
112. F.Catara, E.G.Lanza, M.A.Nagarajan, A.Vitturi
Collective transition densities in neutron rich nuclei
Nucl.Phys. A614(1997)87
113. E.Kwasniewicz, F.Catara e M.Sambataro
Structure of odd A 1s0d- and 1p0f-shell nuclei in the Collective Pair Approximation
Journal of Physics G23(1997)911
114. F.Catara, E.G.Lanza, M.A.Nagarajan, A.Vitturi
Effect of large neutron excess on the dipole response in the of the giant dipole resonance
Nucl.Phys. A614(1997)449
115. F.Catara, Ll.Serra, N.Van Giai
Ground state correlations of jellium metal clusters in local spin-density approximation
Z.Phys. D39(1997)153
102
116. M. Sambataro e J. Suhonen
On the interdependence between ground and one-phonon RPA states Preprint 97,
inviato a Phys. Lett. B
117. M. Sambataro
pn-QRPA and higher-order approximations
Preprint 97, in corso di stampa sui Proceedings del Workshop on calculation of
double-beta-decay matrix elements, Praga (1997)
118. M. Sambataro
QRPA in a boson formalism: an application to beta decay physics
Preprint 97, in corso di stampa sui Proceedings del Sixteenth International Workshop on Nuclear Physics, Rila (Sofia, 1997)
119. A.Insolia, R. Lovas, K. Varga, R.J. Liotta e D.S. Delion
Microscopic theory of cluster radioactivity
Physics Reports (1997) (in press)
120. D.S. Delion, A. Insolia e R.J Liotta,
Pairing Correlation and Quadrupole Deformation Effects on the C1 4 Decay
Phys. Rev. Lett. 78 (1997) 236
121. D.S. Delion, A. Florescu, A. Insolia and R.J. Liotta
Alpha and exotic cluster decay
Proceedings of the Int. Conference on Nuclear Physics, Sanibel Island (Florida,
1997)
122. F. Siringo
Low dimensional ordering on a lattice model
Phys. Lett. A226, 378 (1997)
123. F. Siringo
Variational Migdal-Kadanoff approach to molecular ordering on a lattice
Int. Journal of Mod. Phys. B11, 2183 (1997)
124. F. Siringo, R. Pucci, G.G.N. Angilella
Are light alkali metals still metals under high pressure?
High Press. Research 15, 255 (1997)
125. F. Siringo
Superconductivity in disordered materials
Il Nuovo Cimento D19, 1853 (1997)
126. A. La Magna, R. Pucci
One particle interacting with the acoustical phonons in a discrete chain
Phys. Rev. B55, 6296 (1997)
103
127. A. La Magna, R. Pucci
Mobile intersite bipolarons in the discrete Holstein-Hubbard model
Phys. Rev. B55, 14886 (1997)
128. V. Ivanov, R. Pucci, V. Yarunin, M. Zhuravlev
Psth-integral treatment for localized electrons in the periodic anderson model
Int. Journal of Mod. Phys. B11, 1023 (1997)
129. A.Degasperis, S.V.Manakov and P.M.Santini:
”Multiple-Scale Perturbation beyond the Nonlinear Schroedinger Equation. I”,
Physica D, 100, 187-211 (1997).
130. M. Manas and P. M. Santini:
“Solutions of the Davey - Stewartson II equation with arbitrary rational localization
and nontrivial interaction”;
Physics Letters A 227, 325-334 (1997).
131. A. Doliwa and P. M. Santini:
”Multidimensional quadrilateral lattices are integrable”;
132. M. Manas, A. Doliwa and P. M. Santini:
”Darboux transformations for multidimensional quadrilateral lattices”;
133. A. Doliwa, M. Manas and P. M. Santini:
”Transformations of quadrilateral lattices”;
Preprint ROME1, 1997.
134. J. Cieslinski, A. Doliwa and P. M. Santini:
”The integrable discrete analogues of orthogonal coordinate systems are multidimensional circular lattices”.
135. A. Doliwa, S. V. Manakov and P. M. Santini:
”∂¯ - reductions of the multidimensional quadrilateral lattice I: the multidimensional
circular lattice”.
Preprint ROME1-1172/97. Commun. Math. Phys. (in press).
104
Chapter 23
Publications in SOLID STATE
PHYSICS 1997
136. G. Franzó, S. Coffa, F. Priolo, C. Spinella
Mechanisms and Performances of Forward and Reverse Bias Electroluminescence
at 1.54 µm from Er-doped Si Diodes;
J. Appl. Phys. 81, 2784 (1997)
137. E. Rimini, A. La Ferla, G. Galvagno, S. Coffa, G. Franzó, F. Priolo
Oxygen-Impurity Interactions in Crystalline Silicon: The Cases of Aluminum and
Erbium;
138. F. Priolo, V. Privitera, S. Coffa and S. Libertino,
”Ion beam injected point defects in crystalline silicon: migration, interaction and
trapping phenomena”
139. G. Franzò, S. Coffa and F. Priolo
”Excitation and de-excitation processes in Er-implanted light emitting Si devices”
Mat. Res. Soc. Symp. Proc. Vol. 438, Materials Modifications and Synthesis by
Ion Beam Processing, edited by D. E. Alexander, N. W. Cheung, B. Park, and W.
Skorupa, pag. 459 (1997);
140. M.G. Grimaldi, F. La Via and V. Raineri,
”Reduction of the C49-C54 Ti Si2 phase transformation temperature by reactive Ti
deposition”
Europhysics Letters, Vol. 40, pag. 581 (1997);
141. M.G. Grimaldi, F. La Via, S. Bocelli, M. Galli, F. Marabelli, L. Miglio and F.
Bonoli.
”Kinetics of the C49-C54 Phase Transition in TiSi2: New Indications from Sheet
Resistance, Infrared Spectroscopy and Molecular Dynamics Simulations”
Microelectronics Engineering, Vol. 37/38, pag. 441 (1997);
105
142. A. Terrasi, G. Franzó, S. Coffa, F. Priolo, F. D’Acapito, S. Mobilio
Evolution of the Local Environment around Er upon Thermal Annealing in Er and
O Co-Implanted Silicon;
Appl. Phys. Lett. 70, 1712 (1997)
143. G. Franzó, S. Coffa, F. Priolo
Excitation and De-Excitation Processes in Erbium Implanted Light Emitting Silicon
Devices; in Materials Modification and Synthesis by Ion Beam Processing, edited by
D.E. Alexander, N.W. Cheung, B. Park, W. Skorupa (Materials Research Society,
Pittsburgh, USA, 1997) Mat. Res. Soc. Symp. Proc. 438, 459 (1997)
144. G. Faraci, A. R. Pennisi, J.L. Hazemann:
”XANES of high pressure Kr Clusters in Be and Si”
PHYS. REV. B 56, 12553, 1997.
106
Chapter 24
ACTIVITY OF TECHNICAL AND
AMINISTRATIVE SERVICES
24.1
ACCOUNTING OFFICE
Responsible Person: Dr. C. Mazzeo
The Department budget for 1997 has been of 4,100,000,000 Lit. It has been used to
operate 20 Services, the teaching activity and to support 35 research groups.
Department Services are funded taking into account the total available budget, and
the destination for which funds are granted to the Department.The accounting Office
cares procurements for the normal activity of Services and research groups both within
the Department and at external laboratories.
The total number of people (professors, PhD students, CNR fellows, administrative
and technical personnel, external personel, who are users of the Accounting Office services,
is about 250.
24.2
VAN DE GRAAFF ACCELERATOR
Responsible Person: Salvatore Leotta
L’acceleratore Van de Graaff è utilizzato per misure di interesse nel campo della fisica
dello stato solido, della fisica ambientale e come supporto didattico.
L’apparecchiatura, finanziata del Ministero della Ricerca Scientifica e Tecnologica
all’interno del programma ”Rete di Piccoli Acceleratori”, può accelerare ioni positivi leggeri come protono, deutoni e particelle alfa sino ad un’energia di 2.5 MeV e supporta 2
”beam line”.
Nel corso del 1996 si è attrezzata la linea di fascio n.1 di camera per microanalisi di
profili di idrogeno e di deuterio in targhette solide in configurazione ERDA (Energy Recoil
Diagnostic Analysis). Pertanto la configurazione attuale del V.d.G. risulta:
• Beam line 1: ERDA
• Beam line 2: camera di scattering con sistema goniometrico, utilizzata principalmente per Channeling (una tecnica usata in studi di struttura cristallina e di dan107
neggiamenti dei solidi, etc.) e misure di Backscattering (RBS).
Il personale addetto al V.d.G. cura la manutenzione dell’acceleratore e contribuisce al suo
continuo ”upgrading”, ad es. per ciò che riguarda il sistema da vuoto e di raffreddamento.
Viene inoltre fornita assistenza per modificare o aggiornare gli apparati sperimentali, di
controllo e di acquisizione dati. Il personale garantisce il proprio aiuto ai gruppi di ricerca
nella fase di progettazione di una misura.
Nel 1996 il tempo totale di fascio reso disponibile agli utenti è stato di 1100 ore.
24.3
CRYOGENICS
Responsible Person: Carmelo La China
l servio di criogenia è dotato di un liquefattore di elio Philips PLE 210 equipaggiato
con un ”recover system”, e di due liquefattori di azoto Philips PLN 106. La produzione
annuale di liquidi criogenici è di 1500 litri di elio e 30000 litri di azoto. Il servizio di
criogenia fornisce elio ed azoto liquidi non solo al Dipartimento di Fisica di Catania,
ma anche ad altri istituti di ricerca che operano all’interno del Dipartimento stesso o
presso altri Dipartimenti dell’Università di Catania. Inoltre il reparto fornisce elio liquido
al Dipartimento di Fisica dell’Università di Messina. Il personale tecnico del reparto
garantisce l’assistenza tecnica ai ricercatori per tutta la durata degli esperimenti.
24.4
ELECTRONICS
Responsible Person: Domenico Nicotra
Il servizio elettronica opera all’interno degli Istituti di Fisica e nell’ambito dei temi
specifici fornisce principalmente il supporto ai gruppi di ricerca sperimentali per le loro
attivita’. A tale scopo vengono progettati e realizzati sistemi o parti di essi provvedendo
alla loro installazione nelle sedi operative. Il Servizio dispone anche di sistemi informatici
autonomi che consentono la progettazione con l’ausilio di sofisticati software di CAD
elettonico. Viene fornito altresi’, per i programmi pertinenti, il necessario supporto per
l e attivita’ didattiche e per il funzionamento delle strutture comuni degli Istituti. In
particolare nell’anno 1996 sono state svolte le seguenti attivita’:
- Test, messa a punto e studio configurazioni per il rivelatore CHIMERA;
- Collaudo sotto fascio 1 corona del rivelatore CHIMERA;
- Programmi connessi alle attivita’ del gruppo CLAMKA nella manutenzione ordinaria dello spettrometro magnetico nella sede di esperimento di Uppsala, durante le fasi
preliminari dei turni di misura. Per tale attivita’ sono in fase di realizzazione due circuiti
di controllo per le protezioni contro i sovraccarichi sulle alimentazioni;
- Test di caratterizzazione di PM di nuova concezione;
- Realizzazione di n. 2 partitori passivi per PM R5505 per programmi ”Cluster Metallici”;
- Realizzazione matrici per rivelatore telescopi monolitici esp. TRASMA;
- Test su PM 1398: determinazione risposta segnali luminosi sottosoglia;
108
- Ottimizzazione dello stadio di uscita e realizzazione, in prototipo, di modulo NIM di
”Gate Generator” a 16 canali;
- Manutenzione ordinaria per utenza multipla.
24.5
ION IMPLANTATION
Responsible Person: Orazio Parasole
Nell’anno 1997 l’Impiantatore ionico ha effettuato circa 750 ore di Impianti con vari
elementi quali: H,He,Ge,P, Ar,Kr,N,Ne,Fe,Cu,Zn,As,C,Ni,O.
Tra le attività di ricerca condotte con l’ausilio dell’I.I. sono da sottolineare:
• Impiantazione ionica con He,Ar,Kr su monocristalli di Carburo di Silicio lo studio
della produzione di difetti e amorfizzazione. Inoltre sono stati effettuati impianti di
C2 − H2 su Si ad alta dose (3 1017 ) per sintetiz film di Carburo di Silicio idrogenati;
• Impianti su polimeri (Polistirene, PMMA) per lo studio di modifica di distribuzioni
di pesi molecolari. Sono stati usati vari tipi di Ioni a varie energie per ricavare la
resa di Scission (Rottura di Legami) e Cross Links (Produzione di nuovi legami in
funzione della paerdita di energia dello Ione incidente);
• Irraggiamento di H su Carbone per misure di scattering elastico a bassa energia
(30-100 Kev);
Inoltre sono stati effettuati impianti come processi integrativi a lavori di ricerca presso
l’Istituto di Metodologie e Tecnologie per la Microelettronica (IMETEM) del CNR di
Catania e consistenti principalmente in:
• Studio delle interazioni delle superfici interne alle cavità in Silicio. Lo studio su tali
cavità ottenute appunto nel nostro Dipartimento di Fisica mediante Impiantazione
Ionica di He a varie energie (30-300 Kev) e successivamente trattate con altri processi
presso la ST Microelectronics di Catania ha permesso la determinazione dell’energia
di legame di impurezze di superficie ed alla definizione del meccanismo di cattura.
I dati ottenuti hanno permesso di applicare le cavità all’ingegneria dei difetti nella
progettazione di dispositivi elettronici realizzati con la tecnologia planare in Silicio;
• Studio sulla formazione di strati epitassiali di leghe Gex − Si1−x su Si (100) per
la fabbricazione di transistor ad eterogiunzione Si/Gex Si1−x . Uno dei processi di
realizzazione di tali dispositivi è consistito appunto in impianti di Ge a varie energie
(80-130 Kev) effettuati nel nostro Dipartimento.
24.6
MECHANICAL SHOP
Responsible Person: Mario Mazzeo
109
24.7
VACUUM
Responsible Person: Alfredo Trovato
24.8
LASER LABORATORY
Responsible Person: Natale Marino
Nell’ambito delle direttive formulate dagli organi universitari è stato curato e coordinato il regolare funzionamento del laboratorio laser per le attività di ricerca a medio e
lungo termine che si svolgono lungo due distinte direzioni:
• studio della dinamica delle transizioni di fase solido-liquido-solido indotte sulle superfici dei materiali di interesse per la microelettronica attraverso tecniche specialistiche complesse e ultraveloci (3-30 nanosecondi) di misure in situ di riflettività
risolta nel tempo come potente mezzo di analisi.
• studio dei fenomeni di ablazione e deposizione di materiali diversi, in ambito controllato, di interesse nella medicina e nella microelettronica dove la formazione del
deposito di materiale fà della deposizione laser una tecnica fortemente innovativa di
deposizione di strati sottili e controllati.
Nell’ambito dell’utilizzo dei fondi strutturali della comunità europea si inserisce il progetto
De.L.E (deposizione mediante laser ad eccimeri) responsab il Prof. G. Foti, finalizzato
alla deposizione di idrossiapatite su piccole protesi di interesse medico e tutti i risultati
preliminari sono stati ottenuti in questo laboratorio.
Negli ultimi mesi questa attività ha subito un’attenuazione a causa della riduzione
dell’energia massima disponibile dovuta a problemi di usura della cavità ad eccimeri ed
ai lunghi tempi di consegna dei materiali di ricambio.
È stato curato lo studio e lo sviluppo degli apparati sperimentali utilizzati per le
prove pratiche in due distinti concorsi per ricercatore universitario ed ha collaborato allo
sviluppo dell’apparato sperimentale per le misure su materiali fotoluminescenti presso
l’IMETEM (CNR).
Infine un notevole impegno ha coinvolto lo studio ai fini del recupero ed il restauro
di una parte dell’antico patrimonio strumentale scientifico del Dipartimento in occasione
della mostra allestita per l’innaugurazione del nuovo anno accademico.
24.9
COMPUTER CENTRE
Responsible Person: Ernesto Cangiano
È stata cura del servizio di proporre e cercare di promuovere il potenziamento delle
risorse di calcolo e di trasmissione dati ai livelli piú avanzati e mantenere sempre l’efficenza
del collegamento con tutto il mondo della ricerca scientifica.
Una rete locale ha assicurato agli utenti la possibilità di avvalersi del calcolo centralizzato e distribuito. I mezzi trasmissivi di questa rete locale sono l’Ethernet per i Cluster
Sun e Vax, per i Pc ed i terminali X, e la fibra ottica per il Cluster Alpha Vms e Unix.
110
Esistono tre collegamenti con linee dedicate. Il principale di essi assicura un link
nazionale ed internazionale ed è realizzato con linea CLan frame relay plus con il CNAF
di Bologna con velocità di trasmissione di 512Kb/s. Sono in fase di attivazione due PVC
(circ. virt.) con il CUC di Palermo ed il CISCA (univ. di CT) a 128Kb/s. Gli altri
due collegamenti sono rispettivamente con il LNS (2 Mb/s) e con il gruppo collegato a
Messina (19.2 Kb/s). Sono state attivate anche due linee commutate che consentono agli
utenti un collegamento remoto alla rete locale da una normale linea telefonica.
I principali compiti del servizio sono
• Coordinamento reti geografiche e metropolitane (INFNET, GARR);
• Management dei sitemi centrali e distribuiti;
• Management del Network (Protocolli Decnet, Tcp/Ip, Lat, Netbeui, etc.);
• Management sistemi per Cad/Cam e Cad/Cae;
• Gestione programmi contabilità meccanizzata;
• Consulenza utenti.
Fra i servizi che i Centro di Calcolo mette a disposizione dell’utenza vi sono:
• Applicativi grafici;
• Programmi per analisi dati;
• Word processing (Tex, Latex, etc.);
• Browser Internet (Mosaic, Netscape,etc.);
• Compilatori (Fortran, C, C++, Pascal,etc.);
• Librerie matematiche (Cern, Nag, etc.);
• Posta elettronica;
• File transfer con vari protocolli.
111

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