NSSDCA ID: 1975-057A-07
Mission Name: OSO 8The purpose of this GSFC hard X-ray telescope was to measure the energy spectra of all known X-ray sources above the intensity threshold of 1.E-6 photons/sq cm-s-keV in the energy region .02 to 3 MeV and to search for time variations, both periodic and irregular, in the intensity of the sources detected. The detector consisted of two optically isolated CsI(Na) central crystals shielded by a large, active collimator also made of CsI(Na). The sensitive area was 27.5 sq cm and the FOV was 5-deg FWHM. One of the two central crystals was completely shielded and served as a monitor of the total internal detector background spectrum. The instrument was mounted in the wheel section of the satellite with the axis of its FOV offset by 5 deg from the negative spin axis of the wheel. The minimum detectable intensity of a point source that was brought to within 5 deg of the negative spin axis for greater than 1 day was about 10E-5 photons/sq cm-s-keV at 100 keV. This was determined from the background spectrum measured in orbit. For more information, see B. R. Dennis et al., Space Sci. Inst., v. 3, p. 325, 1977.
Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. Brian R. Dennis | Other Investigator | NASA Goddard Space Flight Center | Brian.R.Dennis@nasa.gov |
Mr. Kenneth J. Frost | Principal Investigator | NASA Goddard Space Flight Center |