GHRS Instrument Science Report 070

"GHRS Dark Noise Monitoring"

Stephen J. Hulbert, Lisa E. Sherbert, and Paul Lee

Abstract excerpted from the Conclusion of the report:

Background dark noise levels for the GHRS have been constant since
launch and continue to be consistent with the original predictions. As
previously seen, the dark noise on Side 1 is less *by almost a factor
of two) than the Side 2 rates and count rates are dependent on
geomagnetic latitude. The particle event detection algorithm currently
used in [STSDAS task] darksum does not appear to be a good predictor
of dark counts from particle event-induced Cerenkov radiation - an
alternated method for rejecting counts due to particle hits is being
investigated. [Many interesting plots included.]