Accession Number : ADA133552

Title :   Far Infrared Radiometric Spectrometer (FIRRS).

Descriptive Note : Final rept. 5 Nov 79-30 May 83,

Corporate Author : GEORGIA INST OF TECH ATLANTA ENGINEERING EXPERIMENT STATION

Personal Author(s) : Bohlander,R A ; Lamm,D R ; Larsen,J W ; Sinclair,M J

PDF Url : ADA133552

Report Date : 29 Jul 1983

Pagination or Media Count : 61

Abstract : This report describes a Far Infrared Radiometric Spectrometer (FIRRS) that will be used to survey radiation in the 0.17 to 1.7 mm wavelength band seen looking down from an aircraft. The instrument was built by the Engineering Experiment Station of Georgia Institute of Technology for the U.S. Air Force Geophysics Laboratory. The instrument is intended for use on an AFGL NKC-135A aircraft. An important initial purpose of the FIRRS will be to determine the effects of atmospheric attenuation and emission. The instrumentation will have two survey functions: (1) It wil measure and calibrate the electromagnetic intensity spectrum received when flying over various terrain and atmospheric conditions. (2) Variations in the scene as the aircraft flies along will cause fluctuations in signal, often called clutter, which will also be analyzed. It is important to determine typical levels of background radiation and its clutter to be able to assess future applications of the far infrared wavelength band. After consideration of alternative spectrometer types, two were selected for inclusion in the FIRRS: a rapid-scanning Michelson interferometer, and a series of narrow-band interference filters. These will be used in different regimes determined by the bandwidth in temporal frequency of the clutter. Both wil give high throughout efficiency. Radiation will be collected by a telescope with an aperture of 190 mm diameter, and will be detected by liquid helium-cooled bolometers and photoconductors.

Descriptors :   *SPECTRORADIOMETERS, *INFRARED SPECTROMETERS, *FAR INFRARED RADIATION, *AIRCRAFT EQUIPMENT, *FLYING LABORATORIES, *ATMOSPHERIC ATTENUATION, EMISSION, CLUTTER, SCANNING, MICHELSON INTERFEROMETERS, NARROWBAND, CALIBRATION, ATMOSPHERE MODELS, BACKGROUND RADIATION, OPTICAL FILTERS, LOW PASS FILTERS, AIRBORNE, STATE OF THE ART

Subject Categories : Aircraft
      Test Facilities, Equipment and Methods
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE