This suite of 5 infrared detector elements is a small representative sample of the ones utilized in the focal plane assembly of the Infrared Astronomical Satellite (IRAS). They consist of photoconductive materials that change in electrical resistance in response to infrared radiation. They were variously constructed from silicon arsenide, antimonide and germanium gadolinium. A total of 62 detectors were mounted at the telescope's focal plane in an assembly that also included such accessories as field lenses and filters that further narrowed the response range. The entire array was cooled to 2.8 degrees K (-269.2 degrees Centigrade) by superfluid liquid helium in order to maximize sensitivity.
Rockwell International built the focal plane assembly and transferred it to the Jet Propulsion Laboratory in 1981 at which time it was integrated into IRAS. This set of elements was transferred to NASM by JPL in 1995.