Cosmic ray hits in the central nervous system at solar maximum
Cosmic ray hits in the central nervous system at solar maximum
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DOI：
10.1016/s0273-1177(99)01015-7
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发表时间：
2000-01-01
期刊：
影响因子：
--
通讯作者：
Kim, MHY
中科院分区：
文献类型：
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作者：
Curtis, SB;Vazquez, ME;Kim, MHY
有人建议在太阳最大值而不是太阳最低值发射载人火星任务，以最大限度地减少银河宇宙射线的辐射暴露。的确，在太阳活动高峰期，高电离粒子对大脑关键区域的命中次数会减少，估计会减少多少是有意义的。我们给出了来自铁离子(z=26)和带电粒子z大于或等于15的粒子在大脑中的几个位置的计算。我们使用了早期论文中用于太阳活动极小值的相同的屏蔽配置和大脑中的位置，以便可以直接比较两种太阳活动条件下的结果。选择简单的压力容器墙和航天器上的设备间作为屏蔽的例子。在设备间，丘脑的典型结果是，任何粒子的3大于或等于15的概率，铁离子的概率从2.3%到1.3%。机房提供的额外屏蔽对这些数字没有什么影响。我们的结论是，这种命中频率的下降(不到两倍)并不能提供一个令人信服的理由，来避免载人火星任务中的太阳极小值。然而，如果发现极少量的点击会导致大脑内的严重故障，这一结论可能会被修正。(C)2000年空间研委会。爱思唯尔科学有限公司出版。
It has been suggested that a manned mission to Mars be launched at solar maximum rather than at solar minimum to minimize the radiation exposure to galactic cosmic rays. It is true that the number of hits from highly ionizing particles to critical regions in the brain will be less at solar maximum, and it is of interest to estimate how much less. We present here calculations for several sites within the brain from iron ions (z = 26) and from particles with charge, z, greater than or equal to 15. The same shielding configurations and sites in the brain used in an earlier paper for solar minimum are employed so that direct comparison of results between the two solar activity conditions can be made. A simple pressure-vessel wall and an equipment room onboard a spacecraft are chosen as shielding examples. In the equipment room, typical results for the thalamus are that the probability of any particles with 3 greater than or equal to 15 and from 2.3 percent to 1.3 percent for iron ions. The extra shielding provided in the equipment room makes little difference in these numbers. We conclude that this decrease in hit frequency (less than a factor of two) does not provide a compelling reason to avoid solar minimum for a manned mission to Mars. This conclusion could be revised, however, if a very small number of hits is found to cause critical malfunction within the brain. (C) 2000 COSPAR. Published by Elsevier Science Ltd.