木星辐射环境不确定性对总剂量风险的影响

以木星探测任务为背景，针对木星辐射带粒子能量高、通量大的强辐射特点，基于器件总剂量辐照试验数据、木星辐射带模型、太阳质子通量模型，将器件失效点剂量不确定性与辐射环境不确定性应用到总剂量设计中，可定量评估特定任务一定屏蔽下的器件失效概率、辐射设计余量(RDM)的置信度及影响因素，可实现木星任务中器件指标、屏蔽厚度和失效概率之间的权衡和优化。首先，根据商业器件TL084辐照试验数据，发现其失效概率分布符合威布尔分布。对于10个木星半径的赤道面轨道，辐射带质子通量比太阳质子大3个数量级，随着屏蔽厚度的增加和任务期的减小，TL084器件所受剂量和失效概率减小。当屏蔽厚度为 10 mm 铝时，器件平均寿命小于2星期。另外，定义并考察了器件的失效速率，失效速率随屏蔽厚度的减小和在轨时间的增加而增加。对于传统的RDM为2的设计方法，1 mm铝屏蔽下对应的置信度为89%。

Influence of Variable Radiation Environment on the TID Evaluation in Jupiter Orbiting Mission

 In a Jupiter exploration mission, the Jovian radiation belt has a strong radiation characteristic with high energy and large flux. Based on the data from the radiation test on device, the Jovian radiation belt model and solar proton model, we introduce a method to evaluate the failure possibility and the confidence level of the RDM (radiation design margin) caused by the total ionizing dose after shielding layers, which includes the radiation environment variability in the Jovian mission. Using this method, we can approach a balance among the device ability, shielding thickness, and failure probability. We find that the Weibull distribution fits the failure possibility of the TL084 experimental data well. For a mission in an equatorial orbit with an altitude of 10 radii of Jupiter, the proton flux of the radiation belt is 3 orders of magnitude larger than solar proton. When the shielding thickness increases and the duration of mission decreases, the failure probability of the TL084 caused by the total dose decreases. The mean lifetime of the TL084 is shorter than 2 weeks after a 10 mm aluminum shielding. In addition, we calculate the failure rate of the TL084. When the shielding layer is thinned and the orbiting period increases, the device fails faster. When the RDM is set as 2, the confidence level after 1 mm aluminum shielding is about 89%.