民航飞机座舱中宇宙辐射中子剂量与飞行高度和地磁纬度关系探讨

Altitude and geomagnetic latitude dependence of neutron dose of cosmic radiation in civil airplane cabin

目的为对民航机组人员飞行中所受宇宙辐射剂量进行全面评估，实测两条国际航线中子剂量并进行分析探讨。方法采用慢化ＢＦ３中子监测器，在北京—纽约和北京—斯德哥尔摩航线飞行的Ｂ－７４７飞机上进行了测量，起飞、着陆阶段每２ｍｉｎ测一次，巡航阶段第３０ｍｉｎ测试一次，高度和纬度利用飞机仪表读出，地磁纬度采用人造地球卫星环境手册的公式计算。以回归法处理中子剂量与飞行高度和地磁纬度的关系，得出曲线及公式。结果实测中子剂量占总剂量的２７％～４５％。北京—纽约航线中子剂量为２．９３６ｍＳｖ／１０００ｈ，北京—斯德哥尔摩航线为３．５０１ｍＳｖ／１０００ｈ，分别占总剂量的３７．５％和４２．３％，与电离成分的比例分别为１∶１．６７和１∶１．３７。宇宙辐射中子剂量随飞行高度增高呈指数型增大，随地磁纬度增高呈直线型增大。结论飞行高度是影响航线中子剂量的第一位因素。

Objective To evaluate the altitude and latitude dependence of neutron dose of cosmic radiation encountered by aircrew of international airlines. Methods A moderated BF 3 proportional neutron counter was used for measurement of neutron dose of cosmic radiation in cabin of B 747 flying from Beijing to New York and Beijing Stockholm Beijing. The altitude and latitude were recorded during the measurement of neutron dose. The data were processed by regression analysis, and the relations among neutron dose, altitude and latitude were obtained. Results It was found that neutron dose of cosmic radiation increased exponentially along with the increase of altitude, and it increased linearly along with the increase of latitude. The neutron doses measured were 2.936 mSv/1000 h and 3.501 mSv/1000 h for Beijing New York and Beijing Stockholm airlines respectively. Conclusion The primary factor influencing the neutron dose of cosmic radiation to be considered was fhying altitude.