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利用香农信息熵的方法验证空间辐射屏蔽后各向同性
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Abstract:
空间辐射是制约载人深空飞行的重要环境因素之一，而人体器官所受的辐射剂量是评估辐射风险和研究防护方法的重要参数。但是，航天员深部器官的剂量只能通过计算得到，无法直接测量。器官剂量计算有直接和分步两种方法，后者可极大减少计算耗时。而经过飞行器屏蔽后舱内辐射能谱是否仍为各向同性，是决定分步计算方法准确性的关键。本文提出了一种利用香农信息熵理论对各向同性进行验证的方法。结果表明虽然屏蔽结构和统计位置会影响粒子分布，但出射粒子仍近似满足各向同性条件，并适用于分步计算的要求。
Space radiation is one of the major factors that limit manned spaceflight. Organ doses are the important parameters for evaluating the health risks encountered by astronauts due to radiation, and are useful parameters in space radiation protection research. However, these organ doses cannot be directly measured in the bodies of astronauts, and can only be calculated. The direct and step-by-step calculation methods are used for calculating organ doses, and the latter method can reduce the calculation time considerably. But the validation of the particle isotropic distribution after shielding by spacecraft is critical in the step-by-step calculation method. In this paper, a method for testing the isotropy of the space radiation spectrum using Shannon entropy is proposed. The results demonstrate that although the shielding structure and statistical position can affect the isotropic distribution of particles, the spectrum of the emergent particles still satisfies an isotropic distribution approximately, and the requirements of the simulation calculation.
| [1] | Kim, M.H.Y., Angelis, G.D. and Cucinotta, F.A. (2011) Probabilistic Assessment of Radiation Risk for Astronauts in Space Missions. Acta Astronautica, 68, 747-759. https://doi.org/10.1016/j.actaastro.2010.08.035 |
| [2] | Gang, B. (2012) The Simulation of Radiation Effects to Astronauts Due to Solar Energetic Particles in Deep Space. Acta Astro-nautica, 71, 32-37. https://doi.org/10.1016/j.actaastro.2011.08.007 |
| [3] | Xu, F., Jia, X., Lu, W., et al. (2017) Utili-zation of Trash for Radiation Protection during Manned Space Missions. Acta Astronautica, 151, 585-594. https://doi.org/10.1016/j.actaastro.2017.12.041 |
| [4] | 祁章年. 载人航天的辐射防护与监测[M]. 北京: 国防工业出版社, 2003. |
| [5] | Xu, F., Jia, X.H., Liu, Q., et al. (2016) Comparison of Organ Doses in Human Phantoms: Varia-tions Due to Body Size and Posture. Radiation Protection Dosimetry, 174, ncw081. https://doi.org/10.1093/rpd/ncw081 |
| [6] | Sun, W., Jia, X., Xie, T., et al. (2012) Construction of Bounda-ry-Surface-Based Chinese Female Astronaut Computational Phantom and Proton Dose Estimation. Journal of Radiation Research, 54, 383-397.
https://doi.org/10.1093/jrr/rrs100 |
| [7] | 张斌全, 余庆龙, 梁金宝, 等. 航天员受银河宇宙线辐射的剂量计算[J]. 北京航空航天大学学报, 2015, 41(11): 2044-2051. |
| [8] | Dietze, G., Bartlett, D.T., Cool, D.A., et al. (2013) ICRP Pub-lication 123. Assessment of Radiation Exposure of Astronauts in Space. Annals of the ICRP, 42, 1-339. https://doi.org/10.1016/j.icrp.2013.05.004 |
| [9] | 中国科学院空间科学与应用研究中心. 宇航空间环境手册[M]. 北京: 中国科学技术出版社, 2000. |
| [10] | Agostinelli, S., Allison, J., Amako, K., et al. (2003) Geant4—A Simulation Toolkit. |
| [11] | 詹青. DNA序列分析中的信息熵应用现状[J]. 生物信息学, 2012, 10(1): 44-49. |
| [12] | 高佛佑. 自然科学与社会科学的交叉点——熵[J]. 天津商业大学学报, 1996, 16(3): 23-26. |
| [13] | Shannon, C.E. (2001) A Mathematical Theory of Communication. The Bell System Technical Journal, 5, 3-55. |
| [14] | Pandey, B. (2013) A Method for Testing the Cosmic Homogeneity with Shannon Entropy. Monthly Notices of the Royal Astronomical Society, 430, 3376-3382. https://doi.org/10.1093/mnras/stt134 |
| [15] | Pandey, B. (2015) A Novel Method for Testing Isotropy with Shannon Entropy. Monthly Notices of the Royal Astronomical Society, 462, 1630-1641. https://doi.org/10.1093/mnras/stw1788 |
| [16] | Sarkar, S. and Pandey, B. (2016) An Information Theory Based Search for Homogeneity on the Largest Accessible Scale. Monthly Notices of the Royal Astronomical Society Letters, 463, L12-L16.
https://doi.org/10.1093/mnrasl/slw145 |
