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Characterization of incomplete fusion in the reactions Ar + KCl at 32,40,52 and 74 MeV/u; Caracterisation de la fusion incomplete dans les reactions Ar + KCl a 32,40,52 et 74 Mev/u

Abstract

Heavy ion collisions at intermediate energies (10 to 100 A.MeV) have been investigated and gave evidence to the persistence of so-called low energy mechanisms such as incomplete fusion. This thesis aims at determining the energy threshold beyond which such a mechanism does not occur any more. First we investigated the so-called conventional incomplete fusion. This mechanism is well known from low energy studies: a thermalized compound nucleus is formed which further de-excites by evaporating particles. Residues will be therefore detected in coincidence with mainly light particles. Ar + KCl at incident energies of 32, 40, 52 and 74 A.MeV has been selected for this analysis. These experiments have been performed using the INDRA multidetector in GANIL (Caen). The detection performance of INDRA allowed to use new analysis methods via global variables. In a first step, global variables have been compared in order to find the one that is the most appropriate to our study. Then incomplete fusion events have been extracted from raw events recorded at incident energies of 32, 40 and 52 A.MeV. It turned out that the contribution of this mechanisms was very weak at 52. A.MeV. It turned out that the contribution of this mechanism was very  More>>
Authors:
Bisquer, E [1] 
  1. Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire
Publication Date:
Dec 20, 1996
Product Type:
Thesis/Dissertation
Report Number:
LYCEN-T-96-46
Reference Number:
EDB-00:108726
Resource Relation:
Other Information: TH: These (D. es Sc.); 47 refs; PBD: 20 Dec 1996
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ARGON IONS; CESIUM IODIDES; CHARGED PARTICLE DETECTION; COMPOUND NUCLEI; COMPUTERIZED SIMULATION; ELECTRONIC EQUIPMENT; ENERGY SPECTRA; EVAPORATION; FOUR-PI DETECTORS; GANIL CYCLOTRON; GEV RANGE 01-10; HEAVY ION FUSION REACTIONS; IONIZATION CHAMBERS; JUNCTION DETECTORS; MULTIPARTICLE SPECTROMETERS; NUCLEAR FRAGMENTATION; PHOTOMULTIPLIERS; POTASSIUM CHLORIDES; SI SEMICONDUCTOR DETECTORS; SOLID SCINTILLATION DETECTORS; TELESCOPE COUNTERS; TOTAL CROSS SECTIONS; TRIGGER CIRCUITS
OSTI ID:
20056797
Research Organizations:
Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire
Country of Origin:
France
Language:
French; English
Other Identifying Numbers:
TRN: FR9704884017849
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
135 pages
Announcement Date:

Citation Formats

Bisquer, E. Characterization of incomplete fusion in the reactions Ar + KCl at 32,40,52 and 74 MeV/u; Caracterisation de la fusion incomplete dans les reactions Ar + KCl a 32,40,52 et 74 Mev/u. France: N. p., 1996. Web.
Bisquer, E. Characterization of incomplete fusion in the reactions Ar + KCl at 32,40,52 and 74 MeV/u; Caracterisation de la fusion incomplete dans les reactions Ar + KCl a 32,40,52 et 74 Mev/u. France.
Bisquer, E. 1996. "Characterization of incomplete fusion in the reactions Ar + KCl at 32,40,52 and 74 MeV/u; Caracterisation de la fusion incomplete dans les reactions Ar + KCl a 32,40,52 et 74 Mev/u." France.
@misc{etde_20056797,
title = {Characterization of incomplete fusion in the reactions Ar + KCl at 32,40,52 and 74 MeV/u; Caracterisation de la fusion incomplete dans les reactions Ar + KCl a 32,40,52 et 74 Mev/u}
author = {Bisquer, E}
abstractNote = {Heavy ion collisions at intermediate energies (10 to 100 A.MeV) have been investigated and gave evidence to the persistence of so-called low energy mechanisms such as incomplete fusion. This thesis aims at determining the energy threshold beyond which such a mechanism does not occur any more. First we investigated the so-called conventional incomplete fusion. This mechanism is well known from low energy studies: a thermalized compound nucleus is formed which further de-excites by evaporating particles. Residues will be therefore detected in coincidence with mainly light particles. Ar + KCl at incident energies of 32, 40, 52 and 74 A.MeV has been selected for this analysis. These experiments have been performed using the INDRA multidetector in GANIL (Caen). The detection performance of INDRA allowed to use new analysis methods via global variables. In a first step, global variables have been compared in order to find the one that is the most appropriate to our study. Then incomplete fusion events have been extracted from raw events recorded at incident energies of 32, 40 and 52 A.MeV. It turned out that the contribution of this mechanisms was very weak at 52. A.MeV. It turned out that the contribution of this mechanism was very weak at 52 A.MeV and even zero at 74 A.MeV. We then investigated events in which three fragments were detected which could possibly sign multifragmentation. We did not find instantaneous multifragmentation with any expansion contribution. We also performed BNV simulations in order to compare our experimental results to model predictions, solving in a semi-classical way the Vlasov transport equation. A good agreement has been obtained on the size of the compound nucleus formed. However the excitation energy has not been reproduced, as the code seems to overestimate the energy taken away by preequilibrium particles. Incomplete fusion decreases as a function of energy but is not replaced by instantaneous multifragmentation with any expansion contribution. (author)}
place = {France}
year = {1996}
month = {Dec}
}