Merging the CEM2K and LAQGSM Codes with GEM2 to Describe Fission and Light-fragment Production

Abstract

We present the current status of the improved Cascade-Exciton Model (CEM) code CEM2k and of the Los Alamos version of the Quark-Gluon String Model code LAQGSM. To describe fission and light-fragment (heavier than He4) production, both CEM2k and LAQGSM have been merged with the GEM2 code of Furihata. We present some results on proton- and deuteron-induced spallation, fission, and fragmentation reactions predicted by these extended versions of CEM2k and LAQGSM. We show that merging CEM2k and LAQGSM with GEM2 allows us to describe many fission and fragmentation reactions in addition to the spallation reactions which are already relatively well described. Nevertheless, the standard version of GEM2 does not provide a completely satisfactory description of complex particle spectra, heavy-fragment emission, and spallation yields, and is not yet a reliable tool for applications. We conclude that we may choose to use a model similar to the GEM2 approach in our codes, but it must be significantly extended and further improved. We observe that it is not sufficient to analyze only A and Z distributions of the product yields when evaluating this type of model, as is often done in the literature; instead it is important to study all the separate isotopic yields as well as the spectra of light particles and fragments.