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5.10 CAM CVF & SWS


In May 1997 cases came to light where the action of a CAM-CVF observation before a SWS observation led to an increased SWS band 3 detector dark current. This increase above the nominal value approached a factor of 100 in some cases. The dark current decreased with time during the SWS observation and reached the nominal dark current less than 30 mins after the CAM-CVF observation. This effect can be seen in affected observations by selecting and plotting all the dark currents from the data (SWSPFLAG bit 27 set) - the dark currents are enhanced and decrease with time. In severe cases this effect can manifest itself in the AAR by band 3 fluxes being negative and in the SPD by the band 3 up and down scans having different shapes.

No correlation between the dark current and the operation of any other instrumental AOT was seen.

All observers who had SWS observations after a CAM-CVF observation were contacted around June 1997. After this date SWS observations were not scheduled until after 30 minutes of a CAM-CVF observation.

K. Leech with contributions from
the SWS Instrument Dedicated Team (SIDT)
and the SWS Instrument Support Team (SIST)