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Background observations on the SMM high energy monitor at energies greater than 10 MeVThe background rate in any gamma ray detector on a spacecraft in near-earth orbit is strongly influenced by the primary cosmic ray flux at the spacecraft's position. Although the direct counting of the primary cosmic rays can be rejected by anticoincident shields, secondary production cannot be. Secondary production of gamma rays and neutrons in the instrument, the spacecraft, and the earth's atmospheric are recorded as background. A 30 day data base of 65.5 second records has been used to show that some of the background rates observed on the Gamma Ray Spectrometer can be ordered to a precision on the order of 1 percent This ordering is done with only two parameters, namely the cosmic ray vertical cutoff rigidity and the instrument's pointing angle with respect to the earth's center. This result sets limits on any instrumental instability and also on any temporal or spatial changes in the background radiation field.
Document ID
19900038266
Document Type
Conference Proceedings
Authors
Forrest, D. J. (New Hampshire, University Durham, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1989
Subject Category
SPACE RADIATION
Funding Number(s)
CONTRACT_GRANT: NAG5-720
Distribution Limits
Public
Copyright
Other