Baffling Test and Calibration of ARPA/AFCRL CVF II Spectrometer
Abstract
This report is on the development of an infrared spectrometer for studies of the infrared emittance and reflectance of the earth's upper atmosphere. The sensor development work features a liquid-helium-cooled, mercury-doped germanium detector and a rotating, circular variable filter (CVF) for spectral scans in the 4- to 13-micrometer range. The filter is an interference type with a film of continuously variable thickness. An optical pulse generator is used to correlate filter position with detector output, and the detector output is channeled through series amplifiers providing four output channels with gains of 1, 10, 100 and 1000. The current test was intended to be the final preflight test of the second-generation spectrometer which incorporated mechanical and electronic improvements as well as a set of optical baffle tubes to improve off-axis rejection. Previous noise levels on the two highest gain channels were unacceptably high and additional data on off-axis rejection was required. Modifications to the sensor were accomplished, primarily to reduce microphonic noise. In addition to off-axis rejection, objectives of the current test were: (1) a check of wavelength calibration, (2) field of view, and (3) relative sensitivity.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1971
- Accession Number
- AD0880526
Entities
People
- Frederick Arnold
Organizations
- Arnold Engineering Development Complex