## 4 Results and Discussion
### Comparison of the Responsivity Temperature Dependence Results and the RTDC Effect  
A comparison between the G(T) values obtained in the instrument-level and detector-level experiments was applied to verify the substitution of the detector-level experiment in RTDC. The comparison is shown in Figure 17. According to two experimental results, the responsivity of the 2250 nm channel in the on-orbit PSAC (T \(\approx-65\)\({}^{\circ}\)C) decreased by 1.3% and 1.5%, compared with those yielded based on a laboratory-based radiometric test (T \(\approx-30\)\({}^{\circ}\)C). As seen in Figure 17, at T \(<-30\)\({}^{\circ}\)C, the two sets of experimental results displayed similar trends that were consistent with the temperature change. The effectiveness of detector-level experiments was basically verified, but there were still some  
Figure 16: G(T) consistency comparison across different heat sink temperatures. The difference between the two sets of results was less than 0.05% after performing temperature correction on the filter transmittance. differences. \(G_{\text{det}}\)(T) shows nonlinear change with T, and the relative change in responsivity is greater compared with \(G_{\text{ins}}\)(T). The reason for this difference may be that the detectors used in the two experiments were not acquired from the same batch of products; notably, unlike the customized detectors used in the PSAC, off-the-shelf products were used in the detector-level experiment. Additionally, due to the different doping concentrations used by certain technologies in production, the responsivity temperature dependence may have varied [26]. Using \(G_{\text{det}}\)(T) to correct changes in PSAC responsivity on a large temperature range may cause deviation. Therefore, in the detector-level experiment, detectors from the same batch as that used in the remote sensor needed to be selected to avoid the impact of batch differences on the experimental results. In instrument-level and detector-level experiments, G(T) was obtained with only one detector measurement dataset. The responsivity temperature dependences of two detectors of the same batch used in PSAC, divided into four photosensitive surfaces based on the instrument-level experimental results, were compared to verify the universality of \(G_{\text{ins}}\)(T). The comparison results are shown in Figure 18; they indicate that the responsivity temperature dependences of the four elements were generally consistent, and the maximum relative deviation was 0.11% in the range of \(-25\)\({}^{\circ}\)C \(<\) T \(<\) \(-70\)\({}^{\circ}\)C. Therefore, the \(G_{\text{ins}}\)(T) obtained with this instrument-level experiment could be used to correct the responsivity temperature dependence of other detectors of the same batch. To further compare the G(T) temperature dependence correction results of the two experiments, in the instrument-level thermal vacuum experiment, the PST was controlled in the range of \(-61\)\({}^{\circ}\)C \(<\) T \(<\) \(-38\)\({}^{\circ}\)C. Additionally, the PSAC continuously observed the integrating sphere through the chopper. The DN was corrected using two G(T) results as T changed. The experimental data showed that the DN decreased by 1.08% when the T decreased from \(-38\)\({}^{\circ}\)C to \(-61\)\({}^{\circ}\)C, and these fluctuations were corrected to 0.38% and 0.34% with \(G_{\text{ins}}\)(T) and \(G_{\text{det}}\)(T), respectively. The DN values yielded before and after correction are shown in Figure 19. The first half of the \(G_{\text{det}}\)(T) correction result displayed a small uptick, which may have been due to the fast cooling rate of the PST and the relatively higher measurement temperatures caused by the thermal resistance between the photosensitive surface and the thermal resistor of the detector. The smaller temperature change rate observed during the second half of the experiment resulted in a significant uptick reduction.