Benchmarking OLTARIS For Deep Space Dose Analyses Using MCNP6

Abstract

OLTARIS, the On-Line Tool for the Assessment of Radiation In Space, is a one-dimensional nuclear transport code developed and utilized by NASA scientists to “study the effects of space radiation on shielding materials, electronics, and biological systems.” While the program has fast run times, and its radiation dose estimates have been validated via certain in situ TLD-100 dosimeter readings aboard the ISS, there are presently no validation methods for deep space environments where there is no geomagnetic protection from GCRs and SPEs.

To provide the groundwork for uncertainty analyses in such scenarios, the author has recreated OLTARIS environments and its 1-D ray-trace method of equivalent dose calculation within MCNP6, a well-validated and verified transport code supported by Los Alamos National Laboratory. MCNP codes include renowned statistical analyses, and with the release of MCNP6 it is now possible to transport exotic deep space particles through a latticed voxel phantom.

The results suggest that, even when limiting MCNP6’s functions to an OLTARIS-like transport, organ equivalent doses and whole body effective dose equivalent calculations in OLTARIS underestimate MCNP6 results by a factor of two. This suggests necessary follow-up studies of the potential sources of error for both codes: for OLTARIS, calculations for deep space environments; and for MCNP6, continued improvement of its deep space geometry.