Improvements to neutron data relevant to GCR transport

There is an existing database of secondary neutron production cross sections and thick-target yields from heavy-ion interactions that have been used extensively for benchmarking transport model calculations such as PHITS, MARS, FLUKA, GEANT4, HETC-HEDS, MCNPX-HI, and SHIELD-HIT. These data are especially relevant to the development of transport models used to simulate Galactic Cosmic Ray (GCR) transport through shielding. Improvements have been made recently to neutron detection efficiency codes that are used to produce the experimental data base. We have re-evaluated some of the existing secondary neutron data using the updated neutron detection efficiency code, and will soon compare the re-evaluated data with PHITS model calculations. The re-evaluation may have an impact for high-energy neutrons that dominate the spectra at forward angles. Based on the data shown in this paper, it appears that the re-evaluation will have a small, negative impact on the overall agreement between data and calculation.