How to Achieve Cooling in Cooled Infrared Detectors

Cooled infrared detectors generally refer to detectors made by utilizing the photon effect between semiconductor materials. The photoelectric effect requires the semiconductor to be cooled to a lower temperature (usually 77K) to achieve the detection function, so the infrared detector needs to be used in conjunction with a cryocooler. At present, the domestic cooling infrared detector materials mainly include MCT, T2SL, etc.

When infrared radiation strikes a detection element, it can excite charge carriers in the element, thereby generating an electric current. However, due to the short carrier lifetime, in order to ensure the sensitivity and resolution of the detector, a refrigeration system is required to cool the detection components to low temperatures, which can effectively reduce the impact of thermal noise. This refrigeration technology usually uses refrigerants, such as liquid nitrogen, refrigerators, etc.

The liquid nitrogen refrigeration of the perfusion type dewar uses the low-temperature characteristics of liquid nitrogen to achieve refrigeration, but the service life of liquid nitrogen is short, the cost is high, and the operation requirements are also very strict.

The refrigeration mechanism uses the principle of isentropic expansion of gas and uses the piston of the expander to output mechanical power. After expansion, the internal energy of the gas increases, which in turn consumes the internal work of the gas itself to compensate, causing the temperature to drop significantly after expansion. For example, the LS734 linear stirling cryocooler developed by GSTiR has the advantages of low power consumption, short cooling time, a lifespan of up to 25,000 hours, and flexible layout.

Following the linear stirling cryocooler, GSTiR has also established a firm foothold in the field of traditional low-temperature refrigerators. For example, the rotating integral stirling cryocooler and the rotary split stirling cryocooler have been put into mass production.

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