TSP #319 - Thermal Camera Cooled to -196C! Cryogenic HgCdTe (MCT) Long-Wave Infrared Detector Magic

In this video Shahriar dives into the amazing science & engineering of cryogenically cooled thermal cameras. This particular model, Inframetrics 760 Imaging Radiometer, was manufactured in the 1990's and leverages a range of clever engineering techniques. It includes a miniaturized Stirling engine cryocooler, galvanometer based mirrors for 2D field scanning as well as a low-noise Mercury-Cadmium-Tellurite (HgCdTe) MCT detector sensitive in the 4-15um wavelength. Teardown of the unit along with a detailed theory of operation is presented. The semiconductor profile and properties of MCT detectors are also discussed. Furthermore, a different thermal camera using a Joule-Thomson cryocooler and high-pressure (3000 PSI) Argon source is also shown. After reverse engineering the critical detector interfaces, an experiment is devised to measure the thermal signature of a resistor. The setup includes a triangle wave driving a resistor to generate a time varying thermal source, Lakeshore M81 source-measure lock-in amplifier and chopper in front of the MCT detector and BLDC motor driver for running the cryocooler. The measurement demonstrates the functionality & sensitivity of the detector to capture black body radiation. Please consider supporting The Signal Path: https://www.TheSignalPath.com/Donate   / thesignalpath   Other links: https://www.TheSignalPath.com   / thesignalpath