Linear Energy Transfer estimates for the CRaTER instrument on LRO

To prepare for a safe return of humans to the Moon, proper studies of the lunar radiation environment and its potential hazards to astronauts are necessary. In June 2009, NASA launched a robotic mission, the Lunar Reconnaissance Orbiter (LRO) mission to find potential safe landing sites, locate potential resources for in situ use, and characterize the lunar radiation environment. The last objective is to be carried out with the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument onboard LRO, which will directly measure the linear energy transfer (LET) spectrum. Of particular interests are heavy charged particles, which are a major radiation risk component of the Galactic cosmic ray spectrum and can penetrate deeply into materials depositing energy and fragmenting and/or fragmenting the target atoms that they impinge upon. 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 in tissue-equivalent material of a variety of Galactic cosmic ray ions and their secondary particles that are expected to be seen by the CRaTER instrument during the LRO mission.