Makalsky L.M., MPEI (TU)
Recording of the intensity change of thermal radiation is necessary for determination of the state of energy objects and communications. As it was written before, the pyrometers, infrared imagers and thermal scanners are used as the devices for recording the thermal radiation. The infrared receivers of thermal radiation usually work in the spectral ranges of 3…5.5 or 8…14 µm. Photon heat absorbers usually work with cryogenic cooling of sensors (for example, with liquid nitrogen having a temperature T = 77 K). It strongly reduces the thermal noise, not removed in the other way, and improves correspondingly the threshold sensitivity. Application of microprocessor or thermoelectric cooling systems under the higher temperatures deteriorates these parameters. Nevertheless, the sensitivity of thermal imaging devices achieves, as a rule, of 0.1°C.