Accession Number : ADA019211

Title :   10.6 Micron (HgCd)Te Photodiode Module.

Descriptive Note : Interim rept. no. 2, 15 Jun 73-15 Aug 74,


Personal Author(s) : Koehler,T.

Report Date : OCT 1975

Pagination or Media Count : 27

Abstract : This report describes the development of a 10.6 micrometers (Hg,Cd)Te thermoelectrically cooled detector module operating at 146 K. The first six months of this program demonstrated the feasibility of 146 K operation by achieving photodiodes with quantum efficiency of 55%, bandwidth of 156 MHz and saturation current of 3 mA at 146 K. The present phase of the program demonstrates the operation of a nine-stage thermoelectric cooler and the TE cooler-detector interface. CO2 laser heterodyne measurements were performed on the unit by AIL division of Cutler-Hammer, Inc., with resultant NEP of 2 x 10 to the minus 13th power W/Hz at 177 K. The cooler did not attain 146 K in the laser tests because of the large detector package surface area and consequently large radiant heat load. The low performance at 10.6 micrometers was attributed to a spectral cutoff wavelength shift of the detector when operated at 177 K instead of 146 K. The nine-stage cooler was found inefficient, requiring 87 watts input power. Because of high quantum efficiencies observed from blackbody measurements at 175 K, it is recommended that a detector be optimized for 10.6 micrometers at 170 K utilizing a six-stage TE cooler requiring less than 20 watts operating power. (Author)

Descriptors :   *Photodiodes, *Infrared detectors, Modules(Electronics), Mercury alloys, Cadmium alloys, Tellurides, Far infrared radiation

Subject Categories : Electrical and Electronic Equipment
      Infrared Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE