Proceedings of SPIE
An elegantly simple cryogenic instrument has been proposed to measure far infrared radiation from starburst galaxies. The experiment—known as WIRE—employs a Cassegrain telescope with diamond-turned mirrors to provide a light-weight optical system for photon collection. A dichroic beamsplitter and filter separate the light into two broad, well-defined bands of interest. Two 128- x 128-pixel arsenic-doped silicon focal plane arrays spatially sample the incoming photons. These arrays feature exceptionally low dark current and low read noise, which allows the coaddition of thousands of images. The entire optical section and focal plane arrays are cooled to 12 Kelvin and 7.5 Kelvin, respectively, by a two-stage, solid-hydrogen cryostat. An uncomplicated electronics package provides some on-board coaddition of images, accepts the simple commands required by the WIRE instrument, and interfaces the data signals to the SMEX spacecraft for telemetry to the ground.
Kemp, John C.; Ames, Harry O.; Esplin, Roy W.; and Allred, Glenn D., "WIRE Instrument Description: Focal Planes, Optics, Electronics" (1994). Space Dynamics Lab Publications. Paper 66.