With the development of China’s crewed space mission,the space radiation risk for astronauts is increasingly prominent.This paper describes a simulation of the radiation doses experienced by a Chinese female voxel ph...With the development of China’s crewed space mission,the space radiation risk for astronauts is increasingly prominent.This paper describes a simulation of the radiation doses experienced by a Chinese female voxel phantom on board the Chinese Space Station(CSS)performed using the Monte Carlo N-Particle(MCNP)software.The absorbed dose,equivalent dose,and effective dose experienced by the voxel phantom and its critical organs are discussed for different levels of shielding of the Tianhe core module.The risk of space-radiation exposure is then assessed by comparing these doses with the current risk limits in China(the skin dose limit for short-term low-earth-orbit missions)and the NASA figures(National Council on Radiation Protection and Measurements Report No.98)for female astronauts.The results obtained can be used to guide and optimize the radiation protection provided for manned space missions.展开更多
We report studies on both target and projectile K-shell ionization by collisions of Cu9＋ ions on the thin Zn target in the energy range of 60-100 MeV. In this work, the relative ratio for the production of the target...We report studies on both target and projectile K-shell ionization by collisions of Cu9＋ ions on the thin Zn target in the energy range of 60-100 MeV. In this work, the relative ratio for the production of the target to projectile K-vacancy is measured. The result shows that it almost remains stable over this energy range and has good consistency with the predictions by vacancy transfer via the 2po-lscr rotational coupling, which gives experimental evidence for K-vacancy sharing between two partners. Furthermore, the discussion for comparisons between the experimental ionization cross sections and the possible theoretical estimations is presented. These comparisons suggest that the experimental data agree well with those predicted by the Binary-Encounter approximation （BEA） model but are not in good agreement with the modified BEA calculations. It allows us to infer that the direct ionization （and/or excitation） is of importance to initial K-vacancy production before 2po-lso transitions in the present collision condition.展开更多
We report light emission during the bombardment of Kr^(17+) ions on an Al surface in the wavelength range 300–700 nm.The three spectral lines of the sputtered Al atoms belong to transitions of Al I–at 309.26,Al I–4...We report light emission during the bombardment of Kr^(17+) ions on an Al surface in the wavelength range 300–700 nm.The three spectral lines of the sputtered Al atoms belong to transitions of Al I–at 309.26,Al I–4s 2S1/2 at 394.72 and Al I 3p^(2)P°_(3/2)–4_(s)^(2)S_(1/2) at 396.50 nm.During the neutralization process,the seven spectral lines of Kr I and Kr II from the incident ion of Kr^(17+)attribute to transitions of Kr I 5p^(2)[3/2]2–7d^(2)[1/2]°1 at 616.33,Kr II 5s ^(2)D_(5/2)–5p ^(2)D°_(3/2) at 410.86,Kr II 5p 4P°_(5/2)–6s 4P_(5/2) at 430.58,Kr II 4d^(2)D_(3/2)–4f ^(2)[3]°_(5/2) at 434.42,Kr II 4d ^(4)D_(1/2)–5p ^(2)S°_(1/2) at 485.80,Kr II 4p ^(4)S_(3/2)–6s ^(4)P°_(3/2) at 618.57 and Kr II 5p 4P°_(3/2)–4d ^(2)D_(5/2) at 656.41 nm.Light emissions of sputtered species depend on energy of the incident ions deposited on the target surface atoms.Light emissions of the neutralized projectiles are formed due to many electrons of the conduction band of the solid surface captured in excited states of the incident ion.展开更多
采用不同材质的刻槽绝缘平行板,包括高纯度石英玻璃、聚四氟乙烯(Teflon)、酚醛树脂(电木)和聚甲醛板(赛钢板),并在15 p A/mm^2～14.3 n A/mm^2范围内改变入射流强,利用1 500 e V电子束入射上述绝缘平行板,实验研究了上述平行板对电子...采用不同材质的刻槽绝缘平行板,包括高纯度石英玻璃、聚四氟乙烯(Teflon)、酚醛树脂(电木)和聚甲醛板(赛钢板),并在15 p A/mm^2～14.3 n A/mm^2范围内改变入射流强,利用1 500 e V电子束入射上述绝缘平行板,实验研究了上述平行板对电子束的导向行为。实验发现,上述电子束通过上述平行板时存在明显的导向现象,其导向行为与束流流强和绝缘材质无关。据此,可排除绝缘平行板内表面沉积电荷自组织充放电过程中,以绝缘材料的面电阻和体电阻对地泄放的线性形式放电过程。展开更多
用345 keV的Kr15+和340 keV的Kr17+离子以45fi角入射n型GaAs单晶(100)面,测量了表面形貌的变化和发射的375—500 nm Ga I和Kr II的特征光谱线.Krq+(q=15,17)离子轰击后表面形貌的变化主要取决于入射离子的电荷态q.离子沉积到靶表面的能...用345 keV的Kr15+和340 keV的Kr17+离子以45fi角入射n型GaAs单晶(100)面,测量了表面形貌的变化和发射的375—500 nm Ga I和Kr II的特征光谱线.Krq+(q=15,17)离子轰击后表面形貌的变化主要取决于入射离子的电荷态q.离子沉积到靶表面的能量引起Ga原子激发,其辐射光谱为Ga I 403.2 nm和Ga I 417.0 nm.入射离子中性化过程中俘获GaAs导带电子形成高激发态原子,通过级联退激填充3p,4d等空穴,P壳层电子跃迁发射谱线为Kr II 410.0 nm,Kr II 430.4 nm,Kr II 434.0 nm和Kr II 486.0 nm,Kr II486.0 nm为较强谱线.实验结果表明,入射离子与GaAs单晶相互作用发射的可见光产额与入射离子的电荷态密切相关,较高电荷态Kr17+离子入射产生的光辐射产额大约为Kr15+离子的两倍.展开更多
基金Project supported by the Open Project Funds for the Key Laboratory of Space Photoelectric Detection and Perception(Nanjing University of Aeronautics and Astronautics),the Ministry of Industry and Information Technology of China(Grant No.NJ2022025-7)the Fundamental Research Funds for the Central Universities(Grant No.NJ2022025).
文摘With the development of China’s crewed space mission,the space radiation risk for astronauts is increasingly prominent.This paper describes a simulation of the radiation doses experienced by a Chinese female voxel phantom on board the Chinese Space Station(CSS)performed using the Monte Carlo N-Particle(MCNP)software.The absorbed dose,equivalent dose,and effective dose experienced by the voxel phantom and its critical organs are discussed for different levels of shielding of the Tianhe core module.The risk of space-radiation exposure is then assessed by comparing these doses with the current risk limits in China(the skin dose limit for short-term low-earth-orbit missions)and the NASA figures(National Council on Radiation Protection and Measurements Report No.98)for female astronauts.The results obtained can be used to guide and optimize the radiation protection provided for manned space missions.
基金Project supported by the Joint Funds of the National Natural Science Foundation of China(Grant No.U1332122)
文摘We report studies on both target and projectile K-shell ionization by collisions of Cu9＋ ions on the thin Zn target in the energy range of 60-100 MeV. In this work, the relative ratio for the production of the target to projectile K-vacancy is measured. The result shows that it almost remains stable over this energy range and has good consistency with the predictions by vacancy transfer via the 2po-lscr rotational coupling, which gives experimental evidence for K-vacancy sharing between two partners. Furthermore, the discussion for comparisons between the experimental ionization cross sections and the possible theoretical estimations is presented. These comparisons suggest that the experimental data agree well with those predicted by the Binary-Encounter approximation （BEA） model but are not in good agreement with the modified BEA calculations. It allows us to infer that the direct ionization （and/or excitation） is of importance to initial K-vacancy production before 2po-lso transitions in the present collision condition.
基金Supported by the National Natural Science Foundation of China under No 11174296.
文摘We report light emission during the bombardment of Kr^(17+) ions on an Al surface in the wavelength range 300–700 nm.The three spectral lines of the sputtered Al atoms belong to transitions of Al I–at 309.26,Al I–4s 2S1/2 at 394.72 and Al I 3p^(2)P°_(3/2)–4_(s)^(2)S_(1/2) at 396.50 nm.During the neutralization process,the seven spectral lines of Kr I and Kr II from the incident ion of Kr^(17+)attribute to transitions of Kr I 5p^(2)[3/2]2–7d^(2)[1/2]°1 at 616.33,Kr II 5s ^(2)D_(5/2)–5p ^(2)D°_(3/2) at 410.86,Kr II 5p 4P°_(5/2)–6s 4P_(5/2) at 430.58,Kr II 4d^(2)D_(3/2)–4f ^(2)[3]°_(5/2) at 434.42,Kr II 4d ^(4)D_(1/2)–5p ^(2)S°_(1/2) at 485.80,Kr II 4p ^(4)S_(3/2)–6s ^(4)P°_(3/2) at 618.57 and Kr II 5p 4P°_(3/2)–4d ^(2)D_(5/2) at 656.41 nm.Light emissions of sputtered species depend on energy of the incident ions deposited on the target surface atoms.Light emissions of the neutralized projectiles are formed due to many electrons of the conduction band of the solid surface captured in excited states of the incident ion.
文摘采用不同材质的刻槽绝缘平行板,包括高纯度石英玻璃、聚四氟乙烯(Teflon)、酚醛树脂(电木)和聚甲醛板(赛钢板),并在15 p A/mm^2～14.3 n A/mm^2范围内改变入射流强,利用1 500 e V电子束入射上述绝缘平行板,实验研究了上述平行板对电子束的导向行为。实验发现,上述电子束通过上述平行板时存在明显的导向现象,其导向行为与束流流强和绝缘材质无关。据此,可排除绝缘平行板内表面沉积电荷自组织充放电过程中,以绝缘材料的面电阻和体电阻对地泄放的线性形式放电过程。
文摘用345 keV的Kr15+和340 keV的Kr17+离子以45fi角入射n型GaAs单晶(100)面,测量了表面形貌的变化和发射的375—500 nm Ga I和Kr II的特征光谱线.Krq+(q=15,17)离子轰击后表面形貌的变化主要取决于入射离子的电荷态q.离子沉积到靶表面的能量引起Ga原子激发,其辐射光谱为Ga I 403.2 nm和Ga I 417.0 nm.入射离子中性化过程中俘获GaAs导带电子形成高激发态原子,通过级联退激填充3p,4d等空穴,P壳层电子跃迁发射谱线为Kr II 410.0 nm,Kr II 430.4 nm,Kr II 434.0 nm和Kr II 486.0 nm,Kr II486.0 nm为较强谱线.实验结果表明,入射离子与GaAs单晶相互作用发射的可见光产额与入射离子的电荷态密切相关,较高电荷态Kr17+离子入射产生的光辐射产额大约为Kr15+离子的两倍.
