Chattaraj Arghya, Selvam T Palani, Vishwakarma R S, Sapra B K
Radiological Physics and Advisory Division, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Mumbai 400 085, India.
Homi Bhabha National Institute, Anushaktinagar, Mumbai 400 094, India.
J Radiol Prot. 2025 Jun 24;45(2). doi: 10.1088/1361-6498/add89c.
This study aims to calculate quality factors () for the radiation environment at low Earth orbit using Monte Carlo-based microdosimetric techniques. This study considers Galactic Cosmic Ray (GCR) ions (= 1-28), trapped protons, and albedo neutrons.is calculated with (2.8 g cmpolyethylene and 10 g cmthick aluminum) and without shielding. FLUKA code is used to model a uniform radiation environment incident on a spherical spacecraft having the above shielding material while a spherical tissue-equivalent proportional counter (TEPC) is positioned at the center of this spherical envelope. The initial fluence spectra of the above radiation fields are based on the OLTARIS code. Microdosimetric distributions in the cavity of the TEPC are calculated separately for GCR ions, trapped protons, and albedo neutrons. Using the microdosimetric distributions,values for these radiations including missionvalues are calculated based on the theory of dual radiation action (TDRA) model, and the formalisms based on ICRP60 and ICRU40.initially increases with theof the ion, but beyond= 22, it becomes insensitive to. Depending on the calculation model, the missionvalue is in the range of 1.91-2.45 for no shielding, 1.67-2.07 for 2.8 g cmpolyethylene shielding, and 1.81-2.48 for 10 g cmaluminum shielding. The microdosimetry-based missionvalues corresponding to 2.8 g cmpolyethylene shielding calculated according to the ICRP60 and ICRU40 models compare well with the published measured values of previous space missions. The calculated TDRA-basedvalues compare well with the values derived from the OLTARIS code. A significant reduction in the dose equivalent is achieved with 10 g cmAl shielding as compared to 2.8 g cmpolyethylene. Overall, the study enhances the understanding of how shielding influencesand dose equivalent.
本研究旨在使用基于蒙特卡罗的微剂量技术计算低地球轨道辐射环境的品质因数（）。本研究考虑了银河宇宙射线（GCR）离子（= 1 - 28）、捕获质子和反照率中子。在有（2.8 g/cm聚乙烯和10 g/cm厚铝）屏蔽和无屏蔽的情况下计算。使用FLUKA代码对入射到具有上述屏蔽材料的球形航天器上的均匀辐射环境进行建模，同时将球形组织等效正比计数器（TEPC）放置在该球形包层的中心。上述辐射场的初始注量谱基于OLTARIS代码。分别针对GCR离子、捕获质子和反照率中子计算TEPC腔内的微剂量分布。利用这些微剂量分布，基于双辐射作用（TDRA）模型理论以及基于ICRP60和ICRU40的形式体系，计算包括任务值在内的这些辐射的 值。最初随离子的 增加而增加，但超过 = 22后，它对 变得不敏感。根据计算模型，无屏蔽时任务值在1.91 - 2.45范围内，2.8 g/cm聚乙烯屏蔽时为1.67 - 2.07，10 g/cm铝屏蔽时为1.81 - 2.48。根据ICRP60和ICRU40模型计算的与2.8 g/cm聚乙烯屏蔽相对应的基于微剂量学的任务值与先前太空任务公布的测量值比较吻合。基于TDRA计算的 值与从OLTARIS代码得出的值比较吻合。与2.8 g/cm聚乙烯相比，10 g/cm铝屏蔽可显著降低剂量当量。总体而言，该研究增进了对屏蔽如何影响 和剂量当量的理解。
