【摘要】 高精度星上辐射基准的建立是提升在轨辐射定标精度的主要技术手段,本文开展了溯源至国际基本单位制(SI)的空间低温绝对辐射基准研究。自主研制高灵敏度低温绝对辐射探测器,设计高热阻的探测器与冷指连接结构以提升灵敏度,通过多级精密温控建立优于0.4 mK的高稳定热环境。采用大冷量两级脉冲管制冷机,通过压缩工质气体的斯特林循环获得20 K的深低温工作环境。建立低温绝对辐射测量链路,评估测量不确定度,并与国家计量科学研究院的基准低温辐射计进行对比。实验结果表明:空间低温绝对辐射计实验样机的灵敏度达到3 565 K/W,对0.4 mW量级激光功率的测量重复性达到0.017%,相对标准不确定度为0.029%;与基准低温辐射计的归一化偏差为0.4,验证了不确定度评估结果的有效性。该工作为研制空间低温绝对辐射计奠定关键技术基础,对基于绝对探测器的在轨辐射定标方法研究具有重要意义。更多还原

【Abstract】 The establishment of a high-precision onboard radiometric benchmark is the primary technical means to improve on-orbit radiometric calibration accuracy. The space cryogenic absolute radiometric benchmark traced to the SI has been researched. First,a high-sensitivity cryogenic absolute radiation detector was developed. A high-thermal-resistance heat transfer structure was designed to connect the detector and cold finger to improve sensitivity. A highly stable thermal environment,better than 0. 4 mK,was established by multistage precise temperature control. Then,a two-stage pulse tube cooler with a large cooling capacity was used to obtain a working environment of 20 K through a Stirling cycle in which the working fluid gas was compressed. Second,an absolute radiation measurement link was built to evaluate the measurement uncertainty. Finally,an indirect comparison was carried out using the reference cryogenic radiometer of the National Institute of Metrology of China. The experimental results illustrate that the sensitivity of the space cryogenic absolute radiometer experimental prototype was 3 565 K/W,the repeatability of 0. 4 mW laser power measurement was 0. 017%,and the relative standard uncertainty was0. 029%. The normalized deviation of the benchmark cryogenic radiometer was 0. 4,and the validity of the uncertainty evaluation results was verified. The research lays a key technical foundation for the development of space cryogenic absolute radiometers. It is important to examine on-orbit radiometric calibration methods based on absolute detectors.更多还原