月壤对太阳粒子事件防护性能研究

Study on Radiation Protection of Lunar Soil against Solar Particle Events

针对载人登月活动中航天员可能遭遇太阳粒子事件,研究了月壤作为防护材料的屏蔽性能。选取了1956和1989年2个典型的太阳粒子事件,计算了在屏蔽不同质子通量的情况下月壤所需的质量厚度,与铝和水进行了比较,并计算了屏蔽后的皮肤剂量;进一步利用蒙特卡洛方法计算了不同截止能量对应质子被屏蔽后的中子和次级质子产额,对质量厚度和次级粒子产额的关系进行了讨论。结果表明:13.43 g/cm^2的月壤可以阻挡1956年和1989年太阳粒子事件中99%的质子,此时皮肤剂量已在剂量限值内;在屏蔽相同数量的质子时,月壤所需的质量厚度小于铝,但大于水;月壤屏蔽后产生的中子产额小于铝。从工程实现的角度考虑,月壤可实现对太阳粒子事件的防护。

The radiation protection capability of lunar soil was studied in this paper to counter the solar particle events （ SPE） which astronauts would probably encounter in manned lunar missions. The shielding mass thickness of the lunar soil was calculated with different shield percentage of pro-ton amounts of 1956 and 1989 SPEs. The mass thicknesses of water and aluminum were compared with that of the lunar soil and the skin dose was calculated. Moreover, the secondary proton and neutron production induced by shielding of different energy protons were calculated with Monte - Carlo method. The relationship between the mass thickness and secondary particle production were discussed. The results indicated that it was possible to block 99% protons in 1956 and 1989 SPEs with lunar soil of 13. 43 g/cm2,in the meantime,the skin dose was under dose limitations; the shielding mass thickness of lunar soil was smaller than that of the aluminum with the same shielding percentage of proton amounts, but the mass thicknesses of aluminum and lunar soil were thicker than that of water. Meanwhile, the neutron production induced by the shielding of lunar soil was smaller than that of aluminum. Therefore, lunar soil could be used for the protection of SPE in the engineer-ing perspective.