Effect of cosmic rays irradiation on the phase change characteristics of an on-orbit fixed point

Abstract Using the phase change characteristics of fixed points to trace the temperature of a spaceborne calibration blackbody is an important technical means to carry out the high-precision on-orbit calibration of thermal infrared remote sensors. In contrast to an experimental environment on the ground, a fixed point will produce radiation damage in the high-energy cosmic rays environment and may affect the phase change characteristics. This study investigates the effect of radiation damage caused by cosmic rays irradiation on the phase change characteristics of fixed points in a spaceborne calibration blackbody. In this research, the simulation method of molecular dynamics was used to simulate the irradiation damage effect of a strong cosmic rays environment on fixed-point indium (In). The experimental system was established to measure the phase change curves of samples with different irradiation doses, and then, the influence of irradiation on the phase change characteristics of the samples was analyzed. The results showed that most of the energy of irradiation was deposited on the In fixed point, resulting in the migration of 0.3% of the displacement atoms inside the In to the gap position to form the Frenkel pairs (FPs). The overcooling of the irradiated In fixed point was reduced by 0.3 $$^\circ \hbox {C}$$ ∘ C , the phase change temperature was increased by 30 mK, and the phase change plateau was more stable.