空间站航天员关键器官辐射剂量学研究

发布时间：2018-02-01 08:27

本文关键词： 空间辐射空间站航天员关键器官 GCR重离子中枢神经系统　出处：《南京航空航天大学》2013年硕士论文　论文类型：学位论文

【摘要】：载人航天是各种航天活动中安全措施要求和标准很高、技术先进程度很高、技术系统最为复杂的航天活动。空间站是一种长期的、技术更加先进的载人航天活动。载人航天活动的快速发展，使得人类可以逐渐地实现十几个小时的太空旅行到长期工作于空间站。对人体关键器官的辐射剂量学研究，不仅对我国长期载人航天活动的深入发展、我国航天能力的提升是必需的，而且对我国航天事业走向深空、持续前进是必不可少的。首先，本文分析了空间站所在近地轨道的辐射场特点，总结归纳了国内外普遍使用的地磁俘获带、宇宙射线模型。基于辐射场模型，得到了空间站所在轨道的捕获带电子、质子和银河宇宙射线GCR粒子谱分布。文章介绍了辐射场粒子与物质的相互作用，文中采用Al材料作为舱体屏蔽材料，选取2g/cm2、5g/cm2、10g/cm2的质量厚度，借助Mulassis一维多层辐射屏蔽仿真程序，计算得到了电子、质子及重离子穿入不同厚度的舱体Al材料，次级电子、γ、核碎片的谱分布。其次，文中详细介绍了数字化人体模型的分类，在人体程式化模型、体素模型和边界表述模型方面，国内外人体模型的特点及发展现状。本文根据中国成年男性数字化人体模型参考值，建立了航天员关键器官（造血器官、皮肤、男性性腺和中枢神经系统）的数学参数化模型。中枢神经系统由脑和脊髓组成，，皮肤由1.741mm厚度的圆柱体、软组织等效材料构成，内嵌人体关键器官，其余部分用软组织填充。再次，采用蒙特卡罗Geant4仿真平台将辐射粒子的能谱作为输入，基于本文人体关键器官模型，对捕获带电子、1972年特大太阳质子事件、太阳活动极小年、极大年GCR质子、典型的重离子在人体关键器官中的能量沉积、吸收剂量、当量剂量量参数，进行了模拟计算和数据分析。研究表明，对于捕获带电子和太阳质子事件，男性性腺的吸收剂量和当量剂量大；对于空间辐射高能GCRs，脊髓和脑中的吸收剂量和当量剂量大，且质子、氦离子对人体关键器官的当量剂量贡献占主要作用；由于GCR重离子辐射权重因子高，其对人体关键器官的当量剂量贡献和累积效应不可忽视。
[Abstract]:Manned spaceflight is a kind of spaceflight activity in which the safety measures and standards are very high, the technology is advanced and the technology system is the most complex in all kinds of spaceflight activities. The space station is a kind of long-term space activity. More advanced technology of manned space activities. Rapid development of manned space activities. So that human beings can gradually realize more than ten hours of space travel to long-term work on the space station. The radiation dosimetry of key organs of human body is not only the in-depth development of long-term manned spaceflight activities in China. The improvement of China's aerospace capability is necessary, and it is necessary for China's aerospace industry to go deep into space and continue to advance. Firstly, this paper analyzes the radiation field characteristics of the space station in low Earth orbit, and summarizes the geomagnetic capture zone and cosmic ray model, which are widely used at home and abroad, based on the radiation field model. The trapped band electron, proton and galactic cosmic ray GCR particle spectrum distribution in the orbit of the space station are obtained. The interaction between particles and matter in the radiation field is introduced in this paper. In this paper, Al material is used as the shielding material of the cabin, and the mass thickness of 2 g / cm 2 / 5 g / m 2 or 10 g / cm 2 is selected, and the simulation program of Mulassis one-dimensional multilayer radiation shielding is used. The spectral distributions of electrons, protons and heavy ions penetrating into different thickness of Al materials, secondary electrons, 纬 and nuclear fragments have been calculated. Secondly, this paper introduces the classification of digital human model in detail, in human programming model, voxel model and boundary representation model. According to the reference value of Chinese adult male digital mannequin model, the key organs (hematopoietic organ, skin) of astronauts were established. The central nervous system is composed of the brain and spinal cord, the skin is made up of a cylindrical body of 1.741mm thickness and the equivalent material of soft tissue. The key organs of the human body are embedded and the rest is filled with soft tissue. Thirdly, using Monte Carlo Geant4 simulation platform, the energy spectrum of radiation particles is taken as input, based on the human body key organ model, the capture band electron, the extraordinarily large solar proton event in 1972. The solar activity is very small and the GCR proton is maximal. The energy deposition, absorption dose, equivalent dose parameters of typical heavy ions in the key organs of human body are simulated and calculated and the data are analyzed. For the capture of electron and solar proton events, the absorbed dose and equivalent dose of male gonad were high. For high energy space radiation GCRs, the absorbed dose and equivalent dose in spinal cord and brain are large, and the contribution of protons and helium ions to the equivalent dose of key organs of human body is dominant. Due to the high weight factor of GCR heavy ion radiation, its equivalent dose contribution and cumulative effect to key organs of human body can not be ignored.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R85;V527

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