Benton E R, Benton E V, Frank A L
Eril Research, Inc., San Rafael, CA 94915-0788, USA.
Radiat Meas. 2002 Oct;35(5):457-71. doi: 10.1016/s1350-4487(02)00076-8.
This paper reports results from the first measurements made on the exterior of a LEO spacecraft of mean dose equivalent rate and average quality factor as functions of shielding depth for shielding less than 1 g/cm2 Al equivalent. Two sets of measurements were made on the outside of the Mir Orbital Station; one near solar maximum in June 1991 and one near solar minimum in 1997. Absorbed dose was measured using stacks of TLDs. LET spectrum from charged particles of LET infinity H2O > o r= 5keV/micrometers was measured using stacks of CR-39 PNTDs. Results from the TLD and PNTD measurements at a given shielding depth were combined to yield mean total dose rate, mean dose equivalent rate, and average quality factor. Measurements made near solar maximum tend to be greater than those made during solar minimum. Both mean dose rate and mean dose equivalent rate decrease by nearly four orders of magnitude within the first g/cm2 shielding illustrating the attenuation of both trapped electrons and low-energy trapped protons. In order to overcome problems with detector saturation after standard chemical processing, measurement of LET spectrum in the least shielded CR-39 PNTD layer (0.005 g/cm2 Al) was carried out using an atomic force microscope.
本文报道了在低地球轨道（LEO）航天器外部进行的首次测量结果，测量内容为等效剂量率均值和平均品质因数随屏蔽深度的变化情况，屏蔽层厚度小于1 g/cm²铝当量。在和平号轨道空间站外部进行了两组测量；一组于1991年6月太阳活动极大期附近进行，另一组于1997年太阳活动极小期附近进行。使用热释光剂量计（TLD）叠层测量吸收剂量。使用CR - 39核径迹探测器（PNTD）叠层测量线能量转移（LET）大于或等于5keV/μm的带电粒子的LET能谱。将给定屏蔽深度下TLD和PNTD测量的结果相结合，得出总剂量率均值、等效剂量率均值和平均品质因数。太阳活动极大期附近的测量结果往往高于太阳活动极小期的测量结果。在最初的1 g/cm²屏蔽层内，平均剂量率和等效剂量率均值均下降了近四个数量级，这表明捕获电子和低能捕获质子均有衰减。为克服标准化学处理后探测器饱和的问题，使用原子力显微镜对屏蔽最少的CR - 39 PNTD层（0.005 g/cm²铝）中的LET能谱进行了测量。
