Gain Notes for Revolution 2688

Another revolution with a TOO observation of a LMXB
	which unfortunately is so strong that it completely
	swamps the Xe line and so the gain determination
	cannot be verified during the period of the TOO. 
Since gain drops below 20 chans/keV on either side of the
	TOO, the whole period is declared a BTI: 
	8663.2 to 8664.3 IJD.

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: Very good, outside of the BTI, unknown within the BTI     
		(within about 3\%\ of ideal, except for settling zone)
JEM-X2: Results coming soon.

CAO 05/10/2023