Gain Notes for Revolution 418
	
JEM-X1: An interesting revolution with poor gain smoothing on one of the
sources. Only data upto about IJD=2267.3 can be used if processed with the
gain history table generated automatically by ISDC. This is caused by outliers
in the source 4 gain history table, created by strong grey filtering of the
data cutting out most of the calibration data for this weak source and causing
confusion with SCO X-1 events spilling over from the rest of the detector.

This problem is now fixed by using OSA 6.0 and later versions. The corrected
gain history table, with the outlying points corrected, is delivered to ISDC
as an instrument characteristics (IC) file. The analysis scripts can find these
IC files if one exists for a particular revolution, and use it instead of the
automatically generated file. If you don't have OSA 6.0 installed, or do not
have the latest IC files us the following quick fix. The results shown here
without the label `uncorrected' have been derived using the IC gain history.

QUICK FIX: Download the corrected gain history table that has all the source
four outliers removed. This is to be found in column `Other data and results' of
the table containing these notes. Put the file in your own private directory 
say <myDir>, and unzip it (gzip -d JMX1_gainHistoryIC_rev0418_001.fits.gz).
When you run the OSA GUI you must correct the hidden parameter gainHist so that
it points the the corrected gain history table:

COR_gainHist = <path to myDir/<myDir>/JMX1_gainHistoryIC_rev0418_001.fits[JMX1-GAIN-OCL,1]

The Xe line analysis done using the IC table shows very acceptable gain
calibration with an average Xe position within 1% of the expected value. Clearly
due to the usual warmup period at the beginning of the revolution, the first
few science windows should be avoided for any analysis requiring the best energy
determination.



JEM-X2: No data and no gain history for this unit


CAO 30/8/2007