Abstract: A sensor with multiple radiation detectors with two or more of the detectors sensitive to a common narrow band of radiation and others of the detector not sensitive to this narrow band of radiation. The detectors may be bolometers with bandpass filters over the bolometers.

Abstract: A nondispersive infrared gas analyzer 10 for indicating the concentration of a selected gas uses a source of radiation 12 to supply radiation to a gas sample chamber 14. The gas chamber 14 functions as an optical channel for transmitting radiation from the source of radiation 12 to both a gas sensing detector 22 and reference detector 24. An inner surface 36 of the gas chamber 14 is an optical reflective surface for the chamber and has a constantly changing irregular profile to greatly enhance optical scattering of the radiation falling on it to provide an uniform disperse radiation output to the detectors 22, 24. Additionally, the source of radiation 12 is chosen to provide radiation which is defocused to further help in attaining homogenous radiation output from the gas sample chamber 14 to the detectors 22, 24.

Abstract: A miniature electronic element is provided formed of and within a single crystal of semiconductor material on which are formed top and bottom surface layers of an oxide of the semiconductor material, and including at least one isolated island of semiconductor material formed in the remaining material between the top and bottom surface layers. Contact members may be attached in predetermined spatial relation to at least one of the top and bottom surface layers and extend through the one surface to the island of material connecting thereto in spaced relation, whereby the material of the island between the contact members provides an electrical path of predetermined value between the contact members. An isolating chamber (or chambers) is formed between the surface layers around the isolated island of material to provide thermal isolation to the island of material.