Fig. 1. Detector Dewar package structure

Fig. 2. (a) Opto-mechanical structure; (b) Radiated spurious ratio and percentage of critical surfaces

Fig. 3. Schematic diagram of Dewar in low temperature optical system

Fig. 4. Radiation spurious ratio versus temperature curve. (a) Dewar window; (b) Dewar window cap

Fig. 5. Window center deformation under different thicknesses

Fig. 6. Radiation spurious ratio of lens barrel with window allowance under different waveband

Fig. 7. Dewar temperature field distribution under 77 K liquid nitrogen

Fig. 8. Cold shield opening height and detector solid angle distribution: (a) 18.3 mm, (b) 23.3 mm, (c) 28.3 mm, (d) 33.3 mm, (e) 38.3 mm, (f) Detector inhomogeneity, average solid angle as a function of cold screen height

Fig. 9. Spurious ratio of lens barrel radiation under different cold screen heights

Fig. 10. Design of cold screen baffle for cold screen diffuse emission

Fig. 11. PST of cold screen

Fig. 12. Color map of on-orbit imaging