Gain Notes for Revolution 2694

Another revolution with a period of strong gain suppresion due
	to the TOO observation of Swift J1727.8-1613
Due to non-verifiablity of the gain determination a BTI
	covers the TOO period from 8678.6 to 8679.6 IJD. Also, for
	most of this period the gain is well below 20 chans/keV,
	making it a doubly bad BTI. 

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: Excellent (within  2% of ideal, except for settling zone and the BTI) 

JEM-X2 rating: Excellent (within about 2% of ideal, except for settling zone and the BTI) 

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 12/10/2023