Abstract: An improved prism cold shield for use in an infrared detection system which includes a detector array comprised of a plurality of detectors sensitive to a radiation of interest in a predetermined wavelength band. The prism comprises a substrate having a top surface partially coated with a first coating layer arranged to define a plurality of bow-like stripes alternating with top surface openings which are covered by a second coating layer. The substrate has a bottom surface partially coated with a third coating layer in a pattern to define a line of windows on the bottom surface which are aligned with the top surface openings so as to define a field of view for the plurality of detectors. The first and third coating layers ae comprised of high absorption, low reflectivity coatings in the wavelength band of the radiation of interest and the second coating layer is an anti-reflective coating.

Abstract: A cold shield for an array of detectors of predetermined shape comprising a first cover of radiation blocking material formed with parallel rows of apertures and lying a first distance away from the detectors and a second cover of radiation blocking material formed with a plurality of apertures of generally the predetermined shape therethrough and lying a second distance, smaller than the first distance, away from the detectors so as to minimize background radiation from reaching the detectors while permitting desired radiation approaching the array from any of a plurality of angles to reach the detectors.

Abstract: A sharp edged aperture for use with radiation sensing apparatus to permit radiation to pass through a relatively thick layer of radiation absorbing material with a minimum of reflection off the edges of the opening by utilizing a thin layer of radiation blocking material overlaying the layer of radiation absorbing material.

Abstract: A device and process for determining the vacuum dewar heat load at cryogenic temperatures by a test made at room temperature are described. The test device comprises a heat source and integral temperature sensor mounted on a probe tip. The heat load of a test dewar at a desired test temperature (e.g. 77K) may be determined by measuring the heat load of the dewar under test at a more suitable test temperature (e.g. room temperature) and multiplying that room temperature heat load by a correlation factor. This correlation factor is empirically determined, and is dependent on the design of the test device and dewar, and the desired and actual test temperatures.

Abstract: An electromagnetic radiation detector has a first surface which receives incident electromagnetic radiation. The sides of the detector are sloped such that incident radiation does not initially strike the sides.