Event generators for simulating heavy ion interactions to evaluate the radiation risks in spaceflight

Simulating the space radiation environment with Monte Carlo codes, such as FLUKA, requires the ability to model the interactions of heavy ions as they penetrate spacecraft and crew member's bodies. Monte-Carlo-type transport codes use total interaction cross sections to determine when a particular type of interaction has occurred. Then, at that point, a distinct event generator is employed to determine separately the results of that interaction. The space radiation environment contains a full spectrum of radiation types, including relativistic nuclei, which are the most important component for the evaluation of crew doses. Interactions between incident protons with target nuclei in the spacecraft materials and crew member's bodies are well understood. However, the situation is substantially less comfortable for incident heavier nuclei (heavy ions). We have been engaged in developing several related heavy ion interaction models based on a quantum molecular dynamics-type approach for energies up through about 5 GeV per nucleon (GeV/A) as part of a NASA consortium that includes a parallel program of cross section measurements to guide and verify this code development