Comparison of nonequilibrium processes inp+Niandp+Aucollisions at GeV energies

Abstract

The energy and angular dependence of double differential cross sections d 2 σ/d dE were measured for p, d, t, 3,4,6 He,6,7,8 Li,7,9,10 Be, 10,11 B, and C produced in collisions of 1.2, 1.9, and 2.5 GeV protons with a Ni target. The shape of the spectra and angular distributions almost does not change whereas the absolute value of the cross sections increases by a factor ∼1.7 for all ejectiles in this beam energy range. It was found that energy and angular dependencies of the cross sections cannot be reproduced by microscopic models of intranuclear cascade including coalescence of nucleons coupled to statistical model for evaporation of particles from excited, equilibrated residual nuclei. The inclusion of nonequilibrium processes, described by a phenomenological model of the emission from fast and hot moving sources, resulting from break up of the target nucleus, leads to very good reproduction of data. Cross sections of these processes are quite large, exhausting approximately half of the total production cross sections. Due to good reproduction of energy and angular dependencies of d 2 σ/d dE it was possible to determine total production cross sections for all studied ejectiles. Results obtained in this work point to the analogous reaction mechanism for proton induced reactions on Ni target as that observed previously for Au target in the same beam energy range.

Production of energetic light fragments in extensions of the CEM and LAQGSM event generators of the Monte Carlo transport code MCNP6

“…18, which compares experimental data for the 7 Li spectrum at 15.6 • from 1.2 GeV p + Ni [21] with results from CEM03.03 and CEM03.03F. Similar results from MCNP6 are presented below in Sec.…”

“…Fig. 25 demonstrates the results for 2500 MeV p + nat Ni → t, 7 Li at 100 • , compared to experimental data measured by Budzanowski et al [21]. The triton spectra again illustrate that MCNP6-F achieves increased production of heavy clusters without "destroying" the established spectra of nucleons and LF with A < 5.…”

“…[19][20][21]). Such simplified moving-source prescriptions are fitted to describe as well as possible only their own measured LF spectra, and have not been developed further to become universal models with predictive power for spectra of LF from arbitrary reactions.…”

Ranking and validation of the spallation models for description of intermediate mass fragment emission from p + Ag collisions at 480 MeV incident proton beam energy

“…It is well known for proton-induced reactions that the qualitative properties of the spectra and angular distributions of the spallation products indicate the presence of two different processes [1][2][3][4][5][6][7][8][9][10][11][12]. One of them contributes to low-energy part of the spectra (energy range smaller than 30-50 MeV), has evaporative-like character and therefore produces isotropic angular distributions.…”

Non-equilibrium processes in p + Ag collisions at GeV energies

“…The double differential spectra d 2 σ/d dE of p, d, t, 3,4,6 He, 6,7,8,9 Li, 7,9,10 Be, and 10,11,12 B were measured at seven scattering angles, 15.6 • , 20…”