@article{oai:repo.qst.go.jp:00046773,
 author = {Hu, Wentao and Pei, Hailong and Li, He and Ding, Nan and Wang, Jufang and He, Jinpeng and Furusawa, Yoshiya and Hirayama, Ryoichi and Matsumoto, Yoshitaka and Liu, Cuihua and Li, Yinghui and Kawata, Tetsuya and Zhou, Guangming and 古澤 佳也 and 平山 亮一 and 松本 孔貴 and 劉 翠華},
 issue = {1},
 journal = {Journal of radiation research},
 month = {May},
 note = {High atomic number and high-energy (HZE) particles in deep space are of low abundance but substantially contribute to the biological effects of space radiation. Shielding is so far the most effective way to partially protect astronauts from these highly penetrating particles. However, simulated calculations and measurements have predicted that secondary particles resulting from the shielding of cosmic rays produce a significant fraction of the total dose and dose equivalent. In this study, we investigated the biological effects of secondary radiation with two cell types, and with cells exposed in different phases of the cell cycle, by comparing the biological effects of a 200 MeV/u iron beam with a shielded beam in which the energy of the iron ion beam was decreased from 500 MeV/u to 200 MeV/u with PMMA, polyethylene (PE), or aluminum. We found that beam shielding resulted in increased induction of 53BP1 foci and micronuclei in a cell-type-dependent manner compared with the unshielded 200 MeV/u Fe ion beam. These findings provide experimental proof that the biological effects of secondary particles resulting from the interaction between HZE particles and shielding materials should be considered in shielding design.},
 pages = {10--16},
 title = {Effects of shielding on the induction of 53BP1 foci and micronuclei after Fe ion exposures.},
 volume = {55},
 year = {2013}
}