Production of Heavy Clusters with an Expanded Coalescence Model in CEM

The production of heavy clusters in nuclear reactions is important in a wide variety of applications: radiation shielding, space engineering and design, medical physics, accelerator design, and more. According to the Cascade Exciton Model (CEM), there are three ways high-energy heavy clusters can be produced. The first way is via coalescence of nucleons produced in the IntraNuclear Cascade (INC). The second way is via the preequilibrium model. The last way is via Fermi breakup. Previous work in CEM examines the impact of expansions of the preequilibrium model and Fermi breakup model on heavy cluster production. The present work studies the impact of expanding the coalescence model on heavy cluster spectra. CEM03.03, the default event generator in the Monte Carlo N-Particle transport code version 6 (MCNP6) for intermediate-energy nuclear reactions, is capable of producing light fragments up to He4 in its coalescence model. In the present study, we have expanded the coalescence model to be able to produce up to Be7. Preliminary results are promising.