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Title: Projectile fragmentation of {sup 40,48}Ca and isotopic scaling in a transport approach

Abstract

We investigate theoretically projectile fragmentation in reactions of {sup 40,48}Ca on {sup 9}Be and {sup 181}Ta targets using a Boltzmann-type transport approach, which is supplemented by a statistical decay code to describe the de-excitation of the hot primary fragments. We determine the thermodynamical properties of the primary fragments and calculate the isotope distributions of the cold final fragments. These describe the data reasonably well. For the pairs of projectiles with different isotopic content we analyze the isotopic scaling (or isoscaling) of the final fragment distributions, which has been used to extract the symmetry energy of the primary source. The calculation exhibits isoscaling behavior for the total yields as do the experiments. We also perform an impact-parameter-dependent isoscaling analysis in view of the fact that the primary systems at different impact parameters have very different properties. Then the isoscaling behavior is less stringent, which we can attribute to specific structure effects of the {sup 40,48}Ca pair. The symmetry energy determined in this way depends on these structure effects.

Authors:
; ;  [1];  [2];  [3]
  1. Joint Institute for Nuclear Research (Russian Federation)
  2. Laboratori Nazionali del Sud, INFN (Italy)
  3. University of Munich, Faculty of Physics (Germany)
Publication Date:
OSTI Identifier:
22612635
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Atomic Nuclei; Journal Volume: 79; Journal Issue: 4; Other Information: Copyright (c) 2016 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; BERYLLIUM 9 TARGET; BOLTZMANN EQUATION; CALCIUM 40 REACTIONS; CALCIUM 48 REACTIONS; DE-EXCITATION; IMPACT PARAMETER; ISOTOPE RATIO; NUCLEAR FRAGMENTATION; SCALING; TANTALUM 181 TARGET; TRANSPORT THEORY

Citation Formats

Mikhailova, T. I., E-mail: tmikh@jinr.ru, Erdemchimeg, B., Artukh, A. G., Toro, M. Di, and Wolter, H. H. Projectile fragmentation of {sup 40,48}Ca and isotopic scaling in a transport approach. United States: N. p., 2016. Web. doi:10.1134/S1063778816040165.
Mikhailova, T. I., E-mail: tmikh@jinr.ru, Erdemchimeg, B., Artukh, A. G., Toro, M. Di, & Wolter, H. H. Projectile fragmentation of {sup 40,48}Ca and isotopic scaling in a transport approach. United States. doi:10.1134/S1063778816040165.
Mikhailova, T. I., E-mail: tmikh@jinr.ru, Erdemchimeg, B., Artukh, A. G., Toro, M. Di, and Wolter, H. H. Fri . "Projectile fragmentation of {sup 40,48}Ca and isotopic scaling in a transport approach". United States. doi:10.1134/S1063778816040165.
@article{osti_22612635,
title = {Projectile fragmentation of {sup 40,48}Ca and isotopic scaling in a transport approach},
author = {Mikhailova, T. I., E-mail: tmikh@jinr.ru and Erdemchimeg, B. and Artukh, A. G. and Toro, M. Di and Wolter, H. H.},
abstractNote = {We investigate theoretically projectile fragmentation in reactions of {sup 40,48}Ca on {sup 9}Be and {sup 181}Ta targets using a Boltzmann-type transport approach, which is supplemented by a statistical decay code to describe the de-excitation of the hot primary fragments. We determine the thermodynamical properties of the primary fragments and calculate the isotope distributions of the cold final fragments. These describe the data reasonably well. For the pairs of projectiles with different isotopic content we analyze the isotopic scaling (or isoscaling) of the final fragment distributions, which has been used to extract the symmetry energy of the primary source. The calculation exhibits isoscaling behavior for the total yields as do the experiments. We also perform an impact-parameter-dependent isoscaling analysis in view of the fact that the primary systems at different impact parameters have very different properties. Then the isoscaling behavior is less stringent, which we can attribute to specific structure effects of the {sup 40,48}Ca pair. The symmetry energy determined in this way depends on these structure effects.},
doi = {10.1134/S1063778816040165},
journal = {Physics of Atomic Nuclei},
number = 4,
volume = 79,
place = {United States},
year = {Fri Jul 15 00:00:00 EDT 2016},
month = {Fri Jul 15 00:00:00 EDT 2016}
}
  • The equilibration of N/Z in heavy-ion reactions is examined by varying the N/Z of the projectile. The reactions studied were {sup 40,48}Ca + {sup 112}Sn at E/A = 35 MeV. Inclusive measurements of light charged particles (LCP: Z{le}2) and intermediate mass fragments (IMF:3{le}Z{le}20) were performed using low threshold ionization chamber-Si-CsI(Tl) detector telescopes and silicon surface barrier telescopes. The kinetic energies, angular distributions, element distributions, mass distributions and the yields of the emitted particles were measured. The influence of the N/Z of the projectile on the relative yields of light charged particles and intermediate mass fragments will be examined. The isotopicmore » ratios of products from the two reactions will be related to N/Z equilibration.« less
  • Capture-fission cross sections for {sup 40,48}Ca+{sup 197}Au and {sup 40,48}Ca+{sup 208}Pb have been measured at beam energies ranging from 195 to 416 MeV. The fissionlike fragments were detected in a pair of position-sensitive multiwire proportional counters and were identified from measurements of position and time using two-body kinematics. The data taken at energies above the barrier (up to 2.4 times the Coulomb barrier) were analyzed in terms of the extra push model showing a strong dependence on the Ca isotope. This dependence was also observed at energies below the barrier, where the results have been interpreted using a schematic coupled-channelmore » code.« less
  • We have measured fragment cross-sections of projectile fragmentation reactions using primary beams of {sup 40}Ca, {sup 48}Ca, {sup 58}Ni, and {sup 64}Ni at 140 MeV/nucleon on {sup 9}Be and {sup 181}Ta targets. The cross-sections were obtained by integrating the momentum distributions of isotopes with Z{>=}5 measured in the A1900 fragment separator. We compare the extracted cross-sections to the predictions of the empirical parametrization of fragmentation cross-sections (EPAX)
  • Ternary breakup of an excited projectile-like fragment produced in mid-peripheral collisions of {sup 124}Xe projectiles with {sup 112}Sn nuclei at E/A=50 MeV is examined. Charge correlations reveal that symmetric breakups occur with significant probability. By selecting on the parallel velocity of the heaviest fragment we minimize the entrance channel dynamics. Calculations with the statistical decay code GEMINI failed to reproduce the experimental charge correlations for any suitable combination of excitation energy and spin considered. A statistical multifragmentation model (SMM) in which breakup of low-density nuclear matter is assumed was able to reproduce the observed charge correlations. The <N>/Z and isotopemore » distributions of fragments were compared to the results of the SMM calculations. Describing the <N>/Z of heavy fragments (Z>6) within SMM suggests that a reduction of the symmetry energy parameter from {gamma}=25 to 14 MeV is necessary. We observe that the yield of neutron-rich isotopes of heavy fragments is particularly sensitive to the symmetry energy.« less
  • The mass of the short-lived radio nuclide {sup 38}Ca (T{sub 1/2}=440 ms) has been measured with the 9.4-T Penning trap mass spectrometer of the Low-Energy Beam and Ion Trap Facility. A mass uncertainty of {delta}m=280 eV has been achieved, corresponding to {delta}m/m=8x10{sup -9}. The result makes {sup 38}Ca, a superallowed beta emitter, a new candidate to test the conserved-vector-current hypothesis. The experiment is also the first demonstration that short-lived radioactive isotopes produced by projectile fragmentation of relativistic heavy-ion beams can be slowed down and prepared such that precision experiments of this kind are possible.