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本文叙述冷却碲镉汞探测器阵列用的双级被动辐射致冷器的结构和性能特点。支承探测器阵列的致冷器,经光调和红外辐射计准直,该辐射计装在自旋-稳定的同步轨道卫星上。在轨道上,致冷器的轴向与地球自转轴平行,与太阳射线的夹角小于±23°。至今已有三台碲镉汞辐射致冷器达到指标,可供飞行使用。双级辐射致冷器能将多元探测器阵列冷却到70～95K,这要取决于探测器的偏压功率、辐射计温度、致冷器-太阳的几何方向以及热-光学元件表面上可能遭到的污染情况。通过一块处于环境温度的太阳隔板和装在致冷级上的去污染加热器,可尽量避免后两种现象引起的性能降低。探测器级加热器也可用作温度控制装置,以使探测器的响应率固定不变。在冷却探测器和发射宇宙飞船期间,予加载的级间支架使探测器保持光学准直。在将杜瓦瓶组件装入致冷器和辐射计之前后,都可在周围环境下用节流致冷器对探测器阵列作冷却试验。辐射致冷器的性能测试是在热真空室内用液氮致冷的黑体背景构成的模拟致冷空间进行的。
This article describes the structure and performance characteristics of a two-stage passive radiation cooler for cooling a HgCdTe detector array. The chiller supporting the detector array is collimated by a photoconductive infrared radiometer mounted on a spin-stable geostationary orbiting satellite. In orbit, the axial direction of the cooler parallel to the Earth's axis of rotation, and the angle of the sun's rays is less than ± 23 °. To date, three HgCdTe radiation coolers have met targets for flight use. Dual-stage radiation coolers can cool multiple detector arrays to 70-95K, depending on the detector's bias power, the radiometer temperature, the cooler-solar geometry, and the thermal-optical surface may be affected To the pollution situation. With a solar panel at ambient temperature and a decontamination heater mounted on the cooling stage, performance degradation due to the latter two phenomena can be avoided as much as possible. Detector-grade heaters can also be used as temperature controls to keep detector response constant. During cooling of the probe and launch of the spacecraft, the loaded interstage support holds the probe in optical alignment. Before and after the Dewar assembly has been installed in the refrigerator and the radiometer, the detector array can be cooled in the ambient environment with a throttling refrigerator. Radiation chiller performance test is carried out in the thermal vacuum chamber with liquid nitrogen cooled blackbody background composed of simulated cooling space.