Infrared detector cooler assemblies with extended operational longevity derive benefits from the utilization of linear compressors. This article is dedicated to the examination of the coating applied to linear compressor piston seals, as even coatings measuring only a few micrometers in thickness can precipitate cryocooler failure. Our investigation delves into the wear resistance characteristics of these coatings. Traditional methods reliant on wear rate for assessing wear may prove inadequate in quantifying micrometer-level wear loss; hence, we introduce a novel indentation method for accurately determining wear depth. This method furnishes a precise means of characterizing micrometer-level wear in the piston coatings of linear compressors. To validate our approach, experiments were conducted using three samples composed of specialized engineering materials. Initially, sample wear resistance was indirectly characterized through scratch width measurements and subsequently assessed directly using the indentation method. Notably, results obtained from both methods were consistent, demonstrating the validity and practicality of employing the indentation method for characterizing micro-level wear in highly resistant materials.
The optical system with variable F-number can simultaneously meet the requirements of sensitivity in wide field of view and the requirements of resolution in narrow field of view, and variable F-number infrared detector is an important part of the optical system. Due to the thermal contact resistance, the temperature of the diaphragms is much higher than that of the cold shield of traditional detector, which means the thermal radiation of the diaphragms would adversely affect the performance of the FPAs. Based on the radiation theory, the effect of thermal radiation of the diaphragms on the performance of FPAs was studied from response signal and NETD, respectively. Furthermore, a MW FPAs and a LW FPAs were calculated by the theory of this paper. The results suggest that the temperature of the diaphragms must be 197K or less if the variation of the performance of the MW FPAs does not exceed 10%. And the temperature of the diaphragms must be 152K or less if the variation of the performance of the LW FPAs does not exceed 10%. The research of this paper has certain guiding significance for the design of Dewar assembly with variable F-number.
This paper reported the research of mid-wavelength infrared (MWIR) HgCdTe focal plane arrays (FPAs) detector with high operating temperature (HOT) at Kunming Institute of Physics. The fabrication of detector FPAs was based on high-quality in-situ indium-doped HgCdTe films grown by Liquid Phase Epitaxy (LPE). The p-on-n planar junction devices was fabricated by arsenic ion implantation technology. The HgCdTe chip arrays, and column-level ADC digital Silicon readout integrated circuit (ROIC) were interconnected to hybrid FPAs by flip-chip bonding using indium bumps. The compact and low-heat-leakage Dewar was designed and used to package the hybrid FPAs, and then one Integrated Dewar Cooler Assembly (IDCA) was prepared by coupling low-power miniaturized Stirling cryocooler to the Dewar. The dark current, noise equivalent temperature difference (NETD) and operability of the detector at different operating temperatures were tested. The test results indicated that the detector could work at the temperature above 150K.
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