On Experimental and Theoretical Studies of Dynamics and Particle Production in p+Nucleus and Heavy Ion Reactions

Research output: ThesisDoctoral Thesis (compilation)

Abstract

Several experiments and theoretical models of intermediate energy heavy ion collision physics are presented in this thesis. Statistical and dynamical aspects of nuclear collisions are widely discussed these days, particularly in connection with the multifragmentation phenomenon and the possible link to a liquid-gas phase transition in the spinodal region of nuclear matter phase diagram. Experimental techniques which allow us to measure various parameters of hot and dense (equilibrated) regions (emission sources) formed in a heavy ion collision are well established nowadays. In recent CHIC (Celsius Heavy Ion Collaboration) experiments the properties of such sources were measured using slowly ramping mode of the CELSIUS storage ring. In this thesis the entropy and chaos production in nuclear collisions is discussed in connection with the t/d/p ratios. Subthreshold pion production explores collective effects in heavy ion collisions and brings additional information about the equation of state (EOS) of nuclear matter. Continuous pion production excitation functions were measured in the beam energy region from far below the nucleon-nucleon threshold up to the delta dominant region. Mass and angular dependencies of pion production are discussed. A version of the molecular dynamics (MD) model which includes pion production in direct nucleon-nucleon collisions was developed and experimental data were analysed in the scope of this model. Properties of the emission sources formed in heavy ion collisions at energies below 50A MeV were studied in the experiments of fragmentation type performed by CHIC. Temperatures of these sources were extracted from fragment energy spectra and from "isotopic effect". A version of the quantum molecular dynamics (QMD) model, where the Pauli potential is introduced into the Hamiltonian, was combined with the statistical multifragmentation model (SMM) and used to explore dynamical and statistical properties of the reaction development. The artificial neural networks were utilized for the analysis of data from the CHICSi detector which is described in details in this thesis.

Details

Authors
  • Anton B Fokin
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Subatomic Physics

Keywords

  • heavy-ion collisions, excitation function, subthreshold pion production, collective effects, entropy and chaos production, d/p ratio, molecular dynamics, artificial neural networks, multifragmentation, Physics, Fysik, Fysicumarkivet A:1998:Fokin
Original languageEnglish
QualificationDoctor
Awarding Institution
Supervisors/Assistant supervisor
  • [unknown], [unknown], Supervisor, External person
Award date1998 Dec 18
Publisher
  • Division of Cosmic and Subatomic Physics, Department of Physics, Lund University
Print ISBNs91-7874-040-1
Publication statusPublished - 1998
Publication categoryResearch

Bibliographic note

Defence details Date: 1998-12-18 Time: 14:15 Place: Föreläsningssal B, Fysiska institutionen, Lund External reviewer(s) Name: Oeschler, Helmut Title: Dr Affiliation: Tyskland ---