Abstract: An infrared imaging system (10) has a detector assembly (12) positioned for viewing infrared radiation from a subject (20), and a housing (18) enclosing the detector assembly for maintaining the detector assembly at a temperature lower than a temperature of an environment outside the housing, the housing having a window (42) for transmission of radiation from the subject to the detector assembly. A cold stop (46) is located within the housing and a warm stop (48) is located outside the housing for transmitting radiation via their respective apertures (50, 52) from the subject to the detector assembly. The warm stop has a planar retroreflective surface (62) for reflecting rays from the detector assembly back to the detector assembly, thereby to minimize thermal noise.

Abstract: Proposed is a device for radiochromatographic analysis of mixtures of substances containing components tagged by radioactive isotopes, such as soft .beta.-isotopes comprising a chromatographic column, a detector of nuclear radiation and a chromatographic detector connected in series along the flow of the substance being analyzed. The detector of nuclear radiation is provided with a cell made as a tube with a scintillator applied onto its inner surface in the form of a solid layer. The tube is provided with movable means for sequentialy cooling and heating the same and a light detector which is movable along the length of the tube. In operation, upon introduction of the portion of the mixture being analyzed into the column, with the heater interacting with the tube, the heater and cooler are moved so that by the time the last component of the mixture exits from the column, the cooler is in interacting relationship with the tube whereby the components of the mixture are frozen.