神舟3号返回舱内的LET分布及吸收剂量

为了测量进入航天器舱内重电离粒子引起的辐射剂量,在神舟3号返回舱的内壁上安装了一个由CR-39片和铝片叠合组成的固体核径迹探测器.对回收的CR-39片进行化学蚀刻处理后,进行扫描并测量了由重电离粒子在CR-39片上形成的径迹斑.参照由重离子加速器的各种离子给出的标定值,在扣除由地面对照样本提供的本底值后,得出了返回舱内的线性能量传递（LET）值的分布,线性能量传递大于探测器记录阈值的总吸收剂量和总等效剂量,以及总等效剂量随屏蔽物厚度的变化.

LET DISTRIBUTION AND ABSORBED DOSE IN SZ-3 RECOVERER

In order to measure the absorbed dose and the dose equivalent induced by heavy ions which enter the space capsule inside, a solid state nuclear track detector is installed in the inner wall of SZ-3 recoverer. This detector is composed by the sandwich of CR-39 sheets and aliminium sheets. The flight time of the detector on board of SZ-3 is about 162 h. After the chemical etching for recoverd CR-39 sheets, we scaned and measured the ion track spots on the CR-39 sheets. Refering to the calibration value for different ions provided by heavy ion accelerator experiment and subtracting the background provided by the contrast samples on the ground, the linear energy transfer （LET） distribution in recoverer are obtained. When the linear energy transfer （LET） is larger than the threshold of the detector, the integral intensity is （4.667±0.071）×10-5cm-2·s-1·sr-1. For LET ＞ 12.6keV/μm （H2O）, the total absorbed dose and the total dose equivalent are （23.50±0.46）μGy and （355.6±9.7）μSv, respectively. The relationship between the total dose equivalent and the thickness of shield are obtained.