Nuclear Medium Effects in the Intranuclear Cascade Calculation.

Abstract

In order to investigate the nuclear medium effects in the intranuclear cascade (INC) model for the nuclear reaction analysis at incident energies between 20 and 200MeV, the ISOBAR code which treats the reflection and refraction was modified to employ the parametrized in-medium nucleon-nucleon (NN) cross sections and the threshold energy for (p, n) and (n, p) reactions. It was found through the calculations of the proton induced reactions on both thin and thick targets of Fe to Pb that ISOBAR with the in-medium NN cross sections gave successful agreement with the experiments for both the neutron and the proton double differential cross sections. In particular, the calculation reproduced the quasi-elastic peak in the neutron energy spectra better than the Bertini-model calculation. Moreover, the accuracy of NMTC/JAERI-MCNP-4A code system for the thick target calculation was also improved significantly by including the ISOBAR code using the in-medium NN cross sections.