Comparisons between transport model calculations and experimental data

A number of transport models such as HETC-HEDS, MCNP-X, HZETRN, PHITS, FLUKA, GEANT, MARS, and SHIELD-HIT have all recently incorporated heavy-ion interactions, and as such they can provide a complete description of Galactic Cosmic Ray (GCR) transport. These models are essential tools for the design of spacecraft, habitats, and instrumentation used in space. In the past decade, benchmark comparisons between experimental data and model calculations have been performed in order to provide a measure of the accuracy of those calculations. There is a large range of data which can be selected for comparison, data that includes measurements of accelerator-based cross sections and thick-target yields. We discuss some of the trends seen in the comparisons, with a focus on the sensitivity of the trends as a function of the projectile/ion system being studied, as well as the charge and mass of the secondary particle. Results indicate the models do well, in general, for heavy and intermediate-mass charged secondaries, but don´t do well for light ion secondaries. In addition, there are significant differences between the models, indicating more work is needed.