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FOC Instrument Science Report 067

FOC Instrument Science Report 067

"History of High Background Events Observed in the f/48 Relay"  11/92
by W. Hack and A .Nota

Abstract excerpted from the report:

This report discusses the occurrences of high background levels in the f/48 
relay up to Day 261 (1992) when the high-voltage supply for the image 
intensifier switched off immediately after powering up. We will give in this
report the history of the occurrences of the high background events and 
provide some statistics to show the flux levels detected by the f/48 relay
during the observations taken prior to the high-voltage shutdown of Day 261.
It is currently believed that the high background rates are the result of a
corona breakdown due to delamination of the potting between the 8kV and 12kV
supply lines to the f/48 intensifier tube.