本文關(guān)鍵詞： 空間輻射 空間站 航天員 關(guān)鍵器官 GCR重離子 中樞神經(jīng)系統(tǒng)　出處：《南京航空航天大學》2013年碩士論文　論文類型：學位論文

【摘要】：載人航天是各種航天活動中安全措施要求和標準很高、技術(shù)先進程度很高、技術(shù)系統(tǒng)最為復雜的航天活動�？臻g站是一種長期的、技術(shù)更加先進的載人航天活動。載人航天活動的快速發(fā)展，使得人類可以逐漸地實現(xiàn)十幾個小時的太空旅行到長期工作于空間站。對人體關(guān)鍵器官的輻射劑量學研究，不僅對我國長期載人航天活動的深入發(fā)展、我國航天能力的提升是必需的，而且對我國航天事業(yè)走向深空、持續(xù)前進是必不可少的。 首先，本文分析了空間站所在近地軌道的輻射場特點，總結(jié)歸納了國內(nèi)外普遍使用的地磁俘獲帶、宇宙射線模型。基于輻射場模型，得到了空間站所在軌道的捕獲帶電子、質(zhì)子和銀河宇宙射線GCR粒子譜分布。文章介紹了輻射場粒子與物質(zhì)的相互作用，文中采用Al材料作為艙體屏蔽材料，選取2g/cm2、5g/cm2、10g/cm2的質(zhì)量厚度，借助Mulassis一維多層輻射屏蔽仿真程序，計算得到了電子、質(zhì)子及重離子穿入不同厚度的艙體Al材料，次級電子、γ、核碎片的譜分布。 其次，文中詳細介紹了數(shù)字化人體模型的分類，在人體程式化模型、體素模型和邊界表述模型方面，國內(nèi)外人體模型的特點及發(fā)展現(xiàn)狀。本文根據(jù)中國成年男性數(shù)字化人體模型參考值，建立了航天員關(guān)鍵器官（造血器官、皮膚、男性性腺和中樞神經(jīng)系統(tǒng)）的數(shù)學參數(shù)化模型。中樞神經(jīng)系統(tǒng)由腦和脊髓組成，，皮膚由1.741mm厚度的圓柱體、軟組織等效材料構(gòu)成，內(nèi)嵌人體關(guān)鍵器官，其余部分用軟組織填充。 再次，采用蒙特卡羅Geant4仿真平臺將輻射粒子的能譜作為輸入，基于本文人體關(guān)鍵器官模型，對捕獲帶電子、1972年特大太陽質(zhì)子事件、太陽活動極小年、極大年GCR質(zhì)子、典型的重離子在人體關(guān)鍵器官中的能量沉積、吸收劑量、當量劑量量參數(shù)，進行了模擬計算和數(shù)據(jù)分析。研究表明，對于捕獲帶電子和太陽質(zhì)子事件，男性性腺的吸收劑量和當量劑量大；對于空間輻射高能GCRs，脊髓和腦中的吸收劑量和當量劑量大，且質(zhì)子、氦離子對人體關(guān)鍵器官的當量劑量貢獻占主要作用；由于GCR重離子輻射權(quán)重因子高，其對人體關(guān)鍵器官的當量劑量貢獻和累積效應不可忽視。
[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, 緯 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.
【學位授予單位】：南京航空航天大學
【學位級別】：碩士
【學位授予年份】：2013
【分類號】：R85;V527

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本文編號：1481414