Thermal design and experiment validation of the focal plane assembly for a low-orbit Extreme Ultraviolet Solar Telescope

The CCD must be kept at a stable low temperature (−50 °C) to maintain long-term two-dimensional sun-tracking of the Extreme Ultraviolet Solar Telescope. A thermal design and optimization method for the focal plane assembly is proposed to meet its thermal control requirements. The dimensions and tilt angles of the heat dissipation cold plates for both components were optimized using SHAP-guided two-stage sampling and Langevin equation optimization algorithm. This resolved the mutual constraints between the CCD and cold trap heat dissipation and accounted for the effects of temperature transients. The thermal simulation results show that the CCD temperature can be set to −50 °C, while ensuring that the cold trap is maintained at a temperature at least 5 °C lower. The cold plates were 164.1 g lighter after optimization and the CCD heating zone used 9.3% less power. The focal plane assembly’s maximum deviation between simulation and experiment was 4.81 °C. Thermal equilibrium experiment results have demonstrated that the CCD temperature is maintained at −50 °C, while the cold trap temperature is kept at least 5 °C lower than that of the CCD. The experiment data obtained in this study met the telescope’s thermal control specifications, thereby verifying the effectiveness of the thermal design method.