Fig. 1. Optical path sketch

Fig. 2. Distance L between remainders and the focal plane-remainders diameter d_max satisfying diffraction curves for different Dewar cold-shielding structures, slant dashed line 2.44λL/C denotes diameter lower limit value for diffraction, shadow region indicates obvious diffraction. Focal plane diagonal length C=15 mm

Fig. 3. Dewar precision assembly sketch

Fig. 4. Fiber remainders. (a) Antistatic gloves fiber; (b) Filter paper fiber; (c) Cotton swab fiber

Fig. 5. Energy spectrum analysis of remainders in an infrared detector

Fig. 6. Images of infrared detector during vibration. (a) Image with black spot; (b) Normal image