Gain Notes for Revolution 2637

Note: this revolution is part of the eclipse season with strong changes in temperature
during each revolution, and some historically low gain periods during which calibration
lines become very weak. This makes calibration a little less certain than usual. However,
despite the gain changing by a factor of more than two, the gain determination gives
energy values within about 5% of ideal, where this can be determined.  

This is one of the later revolutions in the mission where the calibration
sources have become so weak that for the best energy determination an
IC Gain History table is needed. These gain history tables are found
automatically by OSA, or can be downloaded from the DTU FTP site.
 
All offline gain/energy corrections (including the IC tables) are based on the
two Fe calibration sources in JEM-X1, for both units, then corrected iteratively
using the instrument background lines (Xe, backed up by Cu and Mo).

Latest OSA software (version 10 and higher) automatically cuts out the first
Science windows of data from each revolution to ensure that people do not use data
from the instrument-settling period. This process can be overruled, but only by
experienced users.
	
JEM-X1 rating: Good  (within about 4\%\ of ideal, except for settling zone and 
		four weak and missing	misfitted lines)

JEM-X2 rating:  Acceptable (within about 5\%\ of ideal, except for settling zone
and several weak or missing lines that have been misfitted with unphysical widths.)

The JEM-X2 corrections are based on the JEM-X1 Fe calibration sources, since
all the Cd sources are now too weak to use.

CAO 15/05/2023