LET estimate improvements for the CRaTER instrument using HETC-HEDS

摘要

NASA launched a robotic mission to Earth's moon called the Lunar Reconnaissance Orbiter (LRO), in June 2009. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> LRO's objectives are to find potential safe landing sites, locate potential resources for in situ use, and characterize the lunar radiation environment. The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument, which is on the LRO, is directly measuring the Linear Energy Transfer (LET) spectra in the vicinity of the moon. This is necessary for the safe return to the moon of future astronauts. The galactic cosmic ray spectrum has many charged particle components, but particles heavier than helium are a major radiation concern because of their high LET values. They are able to fragment target materials and to fragment themselves, depositing large quantities of energy locally in small volumes. In this work, the radiation transport code HETC-HEDS (High Energy Transport Code - Human Exploration and Development in Space) is used to investigate the LET distributions of primary and secondary particles of the types that are expected to be seen by the CRaTER instrument during the LRO mission.