NASA/TP-2010-21633, NASA TECHNICAL PUBLICATION: SPACECRAFT SOLAR PARTICLE EVENT (SPE) SHIELDING - SHIELDING EFFECTIVENESS AS A FUNCTION OF SPE MODEL AS DETERMINED WITH THE FLUKA RADIATION TRANSPORT CODE (SEP 2010)

NASA/TP-2010-21633, NASA TECHNICAL PUBLICATION: SPACECRAFT SOLAR PARTICLE EVENT (SPE) SHIELDING - SHIELDING EFFECTIVENESS AS A FUNCTION OF SPE MODEL AS DETERMINED WITH THE FLUKA RADIATION TRANSPORT CODE (SEP 2010)., In this paper, we report the results of modeling and simulation studies in which the radiation transport code FLUKA (FLUktuierende Kaskade) is used to determine the changes in total ionizing dose (TID) and single-event effect (SEE) environments behind aluminum, polyethylene, carbon, and titanium shielding masses when the assumed form (ie, Band or Exponential) of the solar particle event (SPE) kinetic energy spectra is changed. FLUKA simulations have fully three spatial dimensions with an isotropic particle flux incident on a concentric spherical shell shielding mass and detector structure. The effects are reported of both energetic primary protons penetrating the shield mass and secondary particle showers caused by energetic primary protons colliding with shielding mass nuclei. SPE heavy ion spectra are not addressed. Our results, in agreement with previous studies, show that use of the Exponential form of the event spectra can seriously underestimate spacecraft SPE TID and single-event environments in some, but not all, shielding mass cases.