National Institute of Radiological Sciences, National Institutes for Quantum Science and Technology, Chiba, 263-8555, Japan.
Sci Rep. 2022 Aug 10;12(1):13617. doi: 10.1038/s41598-022-17079-1.
Shielding from space radiation, especially galactic cosmic rays (GCRs), is a significant safety challenge for future human activities in deep space. In this study, the shielding performances of potential materials [aluminum (Al), polyethylene (PE), and carbon fiber reinforced plastic (CFRP)] were investigated using Geant4 Monte Carlo simulation considering two types of biological scale parameters, the International Commission on Radiological Protection (ICRP) quality factor (QF) and the plausible biological effectiveness (RBE), for GCRs. The effective dose equivalent was reduced by 50% for QF and 38% for RBE when shielding using 20 g/cm of CFRP. A spacecraft made from CFRP will have a better radiation shielding performance than conventional Al-based spacecraft. The contribution of heavy ions for QF based effective dose equivalent was larger by a factor of ~ 3 compared to that for RBE based effective dose equivalent. The shielding materials efficiently reduced the effective dose equivalent due to ions with QF > 3.36 and RBE > 2.26. QF and RBE have advantages and disadvantages in quantifying the dose equivalent of space radiation, and the establishment of a standard parameter specified for a mixed radiation environment occupied by protons and heavy ions is necessary for practical dose assessment in deep space.
为了未来人类在深空的活动，屏蔽来自太空的辐射，特别是银河宇宙射线（GCRs），是一个重大的安全挑战。在这项研究中，使用 Geant4 蒙特卡罗模拟，考虑了两种生物尺度参数（国际辐射防护委员会（ICRP）质量因子（QF）和合理生物效应（RBE）），研究了潜在材料（铝（Al）、聚乙烯（PE）和碳纤维增强塑料（CFRP））的屏蔽性能，用于 GCRs。当使用 20g/cm 的 CFRP 进行屏蔽时，QF 的有效剂量当量减少了 50%，RBE 的有效剂量当量减少了 38%。由 CFRP 制成的航天器将比传统的基于 Al 的航天器具有更好的辐射屏蔽性能。与基于 RBE 的有效剂量当量相比，基于 QF 的有效剂量当量的重离子贡献大了约 3 倍。屏蔽材料有效地降低了 QF>3.36 和 RBE>2.26 的离子的有效剂量当量。QF 和 RBE 在量化空间辐射的剂量当量方面各有优缺点，为了在深空进行实际剂量评估，有必要建立一个针对质子和重离子混合辐射环境的标准参数。
