本文關鍵詞： 空間輻射 Geant4 次級粒子 屏蔽材料 高能重離子　出處：《新疆大學》2016年碩士論文　論文類型：學位論文

【摘要】：空間輻射主要由銀河宇宙輻射、太陽粒子事件和范艾倫地球輻射帶組成�？臻g輻射環(huán)境中的質子、電子、高能重粒子等射線共同作用在航天器上,會對航天器內的宇航員和電子器件系統(tǒng)造成嚴重的影響。當宇航員長時間工作在空間輻射環(huán)境或進行太空行走工作時,射線穿過人體組織與組織細胞發(fā)生相互作用而傳遞能量時,將會誘導基因突變,對人體造成不可修復的嚴重損傷。GEANT4是歐洲核子中心(CERN)開發(fā)的一個用于模擬粒子在物質中輸運過程的工具包,可以用來模擬各種常見的粒子與物質的相互作用,是一種常用的功能強大的蒙卡程序。在此我們根據(jù)需要,選擇合適的相互作用過程和物理模型,并構建不同幾何形狀的屏蔽層,以達到最佳的仿真效果空間輻射環(huán)境。對各種粒子和射線在不同屏蔽體中的輸運過程進行模擬,并計算屏蔽體后吸收體模型內的能量沉積、深度劑量分布、入射的初級次級粒子類型及能譜等。得到航天員在空間輻射下屏蔽后太空艙內的輻射環(huán)境,為進一步分析太空艙中宇航員及電子器件的吸收劑量提供模擬數(shù)據(jù),為保障航天員在軌飛行的人身安全提供數(shù)據(jù)支持。本文使用基于蒙特卡羅方法的GEANT4軟件模擬空間高能1GeV/n~(56)Fe離子入射質量厚度為1.35g/cm~2的鋁、聚乙烯、碳和水四種屏蔽材料,分析透射屏蔽體的初級粒子及由屏蔽材料產生的次級電子、次級中子、次級質子和次級γ的能譜,屏蔽體產生的次級粒子入射水吸收體中的能量沉積及其深度劑量分布。分析產生的次級重粒子類型和能量,比較四種屏蔽材料對高能~(56)Fe離子的屏蔽性能。結果發(fā)現(xiàn):1:對于空間高能1GeV/n ~(56)Fe離子入射質量厚度為1.35g/cm~2的鋁、聚乙烯、碳和水四種屏蔽材料,聚乙烯材料的對高能Fe粒子的阻止本領最強,吸收能量最多為2.16×10~7MeV,初級粒子穿過屏蔽材料的能量最小,其次是液態(tài)水屏蔽效果較好,對高能Fe粒子屏蔽效果最差的為鋁材料,僅吸收能量1.67×10~7MeV。2:由屏蔽材料產生的次級粒子中,次級中子和次級質子的能譜范圍較廣,能量較大,次級電子和次級γ射線的能譜相似,主要能量集中在0.1MeV處和30keV處。3:對于次級粒子在水吸收體中的能量沉積,次級電子和次級γ射線主要將能量沉積在吸收體表面,而次級中子和次級質子能夠到達吸收體內部,沉積能量隨吸收體深度的變化較緩。4:對于質量厚度為1.35g/cm~2的鋁、聚乙烯、碳和水四種屏蔽材料,產生的次級重荷主要為靠近Fe原子序數(shù)在22到26之間的次級重核。原子序數(shù)在3到10之間的次級粒子產生較少。
[Abstract]:Space radiation is mainly composed of galactic cosmic radiation, solar particle events and Van Allen Earth radiation belt. The protons, electrons, high-energy heavy particles and other rays in the space radiation environment act together on the spacecraft. Can have a serious impact on astronauts and electronic device systems in spacecraft. When astronauts work long hours in a space radiation environment or perform spacewalk work, When radiation passes through the body's tissues and cells and transfers energy through it, it induces gene mutations. Severe irreparable damage to the human body. GEANT4 is a toolkit developed by the European Nuclear Center (CERN) to simulate the transport of particles in matter, which can be used to simulate the interaction of a variety of common particles with matter. Is a common powerful Monka program. Here we choose the appropriate interaction processes and physical models, and construct different geometric shielding layers. In order to achieve the best simulation effect, the transport process of various particles and rays in different shielding bodies is simulated, and the energy deposition and depth dose distribution in the model of absorber behind the shield are calculated. The radiation environment of the capsule after the astronauts are shielded under space radiation is obtained, which provides simulation data for further analysis of the absorbed doses of astronauts and electronic devices in the capsule. In order to provide data support for the safety of astronauts in orbit flight, this paper uses GEANT4 software based on Monte Carlo method to simulate four shielding materials, aluminum, polyethylene, carbon and water, with incident mass thickness of 1.35 g / cm ~ (2) for high energy 1 GeV / N ~ (-1) N ~ (-1) N ~ (-1) N ~ (-1) C ~ (-1) Fe ion in space. Analyzing the primary particles of the transmission shield and the energy spectra of secondary electrons, secondary neutrons, secondary protons and secondary 緯 produced by the shielding materials, Energy deposition and depth dose distribution in secondary particles incident into water absorbers produced by shield. Type and energy of secondary heavy particles, The shielding properties of four kinds of shielding materials for high energy ~ (56) Fe ions are compared. The results show that: 1: 1: for aluminum, polyethylene, carbon and water four shielding materials with incident mass thickness of 1.35 g / cm ~ (2) for high energy 1 GeV / n / n ~ (-1) ~ (-1) GE ~ (-1) N ~ (-1) O ~ (-1) Fe ions, The PE material has the strongest blocking power to the high-energy Fe particles, the absorption energy is 2.16 脳 10 ~ (7) MeV at most, the primary particles have the lowest energy through the shielding materials, the liquid water shielding effect is better, and the aluminum material has the worst shielding effect on the high-energy Fe particles. The absorbed energy is only 1.67 脳 10 ~ (7) MeV. 2: among the secondary particles produced by shielding materials, the energy spectrum of secondary neutron and secondary proton is larger and the energy of secondary neutron and secondary proton is larger, and the energy spectrum of secondary electron and 緯 -ray is similar. The main energy is concentrated at 0.1MeV and 30keV. 3: for the energy deposition of secondary particles in water absorbers, secondary electrons and secondary gamma rays mainly deposit energy on the surface of the absorbers, while secondary neutrons and secondary protons reach the absorbing body. The deposition energy varies slowly with the depth of the absorber. 4: for aluminum, polyethylene, carbon and water shielding materials with a mass thickness of 1.35 g / cm ~ (-2), The secondary heavy loads are mainly secondary heavy nuclei close to the atomic number of Fe between 22 and 26, and the secondary particles with atomic number between 3 and 10 produce less.
【學位授予單位】：新疆大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：V445.16;V520.6

【相似文獻】

相關期刊論文 前4條

1 余文軍;孟憲文;;電子線射野大小對深度劑量分布影響的研究[J];醫(yī)療裝備;2012年09期

2 李強,衛(wèi)增泉,李文建;中能重離子束深度劑量分布計算[J];高能物理與核物理;2000年05期

3 巴維真,張明健,周光文;電子束在硅中的能量損耗[J];輻射研究與輻射工藝學報;1987年02期

4 ;[J];;年期

相關會議論文 前2條

1 黨秉榮;衛(wèi)增泉;李文建;李強;周光明;溫小瓊;袁世斌;王菊芳;頡紅梅;郝冀芳;馬秋峰;;中能重離子深度劑量曲線理論計算[A];第十一屆全國核物理大會論文集[C];2000年

2 穆向魁;;腫瘤質子治療原理及臨床應用[A];第七屆全國醫(yī)用加速器學術交流會論文集[C];2006年

相關碩士學位論文 前1條

1 荀明珠;不同材料對空間輻射屏蔽特性的蒙特卡羅模擬研究[D];新疆大學;2016年

，

本文編號：1497902