Gain Notes for Revolution 300
	
JEM-X 2:Our most intractable revolution to date. This is a Crab calibration revolution
for which JEM-X2 was activated after a long dormant period. The very steep 
gain increase graphically illustrates the phenomenon of `rapid gain aging',
recreating the upward gain drift, caused by months of activation, in just a few
hours. Unfortunately, this large gain increase and large gaps in the gain
history table during the settling period conspired to create a gain curve that
j_cor_gain 6.3 could not handle. As demonstrated by the figure of the Cd peaks,
j_cor_gain 6.4 has no problem.

Compare this data with that for JEM-X1 which had been switched on continuously 
since revolution 170, and behaved quite normally during the same period.

ISDC reprocessed the JEM-X2 raw spectral calibration data (FRSS spectra) 
using j_calib_gain_fitting 7.2 and made a new gain history table which is now
in /isdc/arc/rev_2/scw/0300/rev.002/idx/jemx2_aca_frss_index.fits.gz

It is this gain history table that should be used to analyse science data in
this revolution for JEM-X2, using j_cor_gain 6.4 or later. The results presented
here were created using the rev.002 gain history table.

The first part of this revolution where the gain and SPAG of the detector are
changing very rapidly are now officially designated a Bad Time Interval (BTI)
and will be ignored by ISDC analysis software. The BTI is IJD= 1913.80 to
1914.30.

CAO 10/11/2006

New Xe line analysis added to archive during creation of new JEM-X2 IMOD epochs
(12 and 13) with new reference channels.

CAO 19/10/2007