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Polyethylene as a radiation shielding standard in simulated cosmic-ray environments

Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States; Japanese Aerospace Exploration Agency, 2-1-1 Tskuba-shi, Ibaraki 305-8505, Japan; National Institute of Radiological Science, 4-9-1 Anagawa, Chiba, Japan; National Space Science and Technology Center, 320 Sparkman Drive, Huntsville, AL 35805, United States
Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms (Impact Factor: 1.19). 01/2006; DOI: 10.1016/j.nimb.2006.08.019

ABSTRACT Radiation risk management for human space missions depends on accurate modeling of high-energy heavy ion transport in matter. The process of nuclear fragmentation can play a key role in reducing both the physical dose and the biological effectiveness of the radiation encountered in deep space. Hydrogenous materials and light elements are expected to be more effective shields against the deleterious effects of galactic cosmic rays (GCR) than aluminum, which is used in current spacecraft hulls. NASA has chosen polyethylene, CH2, as the reference material for accelerator-based radiation testing of multi-function composites that are currently being developed. A detailed discussion of the shielding properties of polyethylene under a variety of relevant experimental conditions is presented, along with Monte Carlo simulations of the experiments and other Monte Carlo calculations in which the entire GCR flux is simulated. The Monte Carlo results are compared to the accelerator data and we assess the usefulness of 1 GeV/amu 56Fe as a proxy for GCR heavy ions. We conclude that additional accelerator-based measurements with higher beam energies would be useful.

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