Gain Notes for Revolution 891
	
JEM-X1: No scientific data or gain history for this unit.


JEM-X2: This is the first revolution in a series of observations of
SCO X-1 where the very strong astronomical source has at times confused
the calibration software causing strange values to appear in the gain history
table generated at ISDC.

To get optimal results with this revolution it is necessary to use the IC gain history
table that has been created offline at DNSC, instead of the gain history table
created automatically by OSA. If you have the newest package of IC files from ISDC
and these are correctly installed, OSA will find the IC gain history table automatically
and you don't need to do anything. However, if you don't have the IC gain table
package from ISDC you can download the table from the gain history archive by
anonymous ftp through the link provided. Download the table to some suitable
subdirectory for your analysis, then set the hidden OSA parameter gainHist:
gainHist="<my subdirectory>/<IC filename>". These files are used instead of the
automatically generated gain history tables wherever there has been an unusual or
non-linear behaviour of the detector gain.

Results shown here are for both the automatically generated gain history table and the
IC table created offline, just to compare the differences in results.
Gain correction using the IC table is very good with all but the first science
windows witin 2% of the ideal value. As always it is advised that users do not use
the first science windows for spectrally sensitive applications since this is where
the instrument is warming up and gain and spatial gain variation vary in ways that
cannot be corrected for.



CAO 04/02/2010