A Model Comparison Study of Fragment Production in 140AMeV^58,64Ni+⁹Be Reactions

Abstract

The cross sections of fragments produced in the 140 A MeV58,64Ni+9 Be projectile fragmentation reactions are calculated by using the antisymmetrized molecular dynamics (AMD) model, the modified statistical abrasion-ablation (SAA) model, and the empirical EPAX2/EPAX3 formulae. The Gogny-g0 interaction is taken as the effective nucleon-nucleon interaction in the AMD calculation, and the decays of fragments obtained from the AMD results are calculated by using the GEMINI code. The calculated cross sections of fragments are compared.

Isobaric yield ratio difference between the140AMeVNi58+BeQiao1, Wei2, Ma3 et al. 2015Phys. Rev. C12070View full textAdd to dashboardCite

“…The isotopic distributions in the 140A MeV 58,64 Ni + 9 Be reactions calculated by the SAA, AMD, AMD + GEMINI and EPAX2/EPAX3 models have been compared in our recent work [25,40]. The AMD and AMD + GEMINI simulations can reproduce the cross sections for the symmetric fragments, but overestimate the cross sections of the neutron-rich fragments.…”

“…The IBD plateaus for the measured 140A MeV 48 Ca/ 48 Ca + 9 Be reactions [18] have been estimated to be around 1.85 ± 0.25 [3,7,20]. Assuming that for the 40 Ca reaction ρ n /ρ p =1, for the 48 Ca reaction, one has ∆lnρ np = 1.85. A relationship between ∆µ/T and ∆ρ np for the calcium reactions has been roughly shown [6], in which ∆µ/T = 1.85, 1, and 0.5 correspond to ∆ρ np of 0.015, 0.009, and 0.004 fm −3 , respectively.…”

“…Based on the isobaric yield ratio (IYR), the IBD method provides cancellation of both the system dependence parameters [8][9][10][11], the free energies of isobars [3], and the terms contributing to the free energy of fragments [8,[12][13][14][15][16] in the formula determining the cross sections of fragment. The target dependence of IBD has been studied by investigating the measured fragments in 140A MeV 40,48 Ca and 58,64 Ni projectile fragmentation reactions on the 9 Be and 181 Ta targets [17], which have been performed by Mocko et al at the National Superconducting Cyclotron Laboratory (NSCL) in Michigan State University [18]. In addition, the Shannon information entropy theory is also adopted to explain the IBD method for a better understanding of it [19,20].…”

Shannon information entropy in heavy-ion collisions

“…A comparison among the cross sections of fragments by the SAA, expax2 [289] and epax3 [290], as well as the measured results for the 140 MeV/u 64 Ni, 58 Ni + 9 Be reactions can be found in Ref. [117]. Some isobaric yield distributions for the fragments in the simulated reactions can be found in Ref.…”

“…In Refs. [117,118], it can be seen that the cross sections of the primary fragments simulated by the AMD model have a large difference to those of the measured results. It is easy to find in Figure 17 that, a relatively large fluctuation in ∆In (I+2m,I,A) /m for the primary fragments obtained by the AMD simulations.…”