Gain Notes for Revolution 2683

This revolution contains a TOO observation of the active blackhole
	Swift J1727.8-1613 during which there is strong Grey Filtering
	which causes the Xe line to disappear - hence it is impossible
	to determine how good or bad the energy determination is during
	this period. 
Throughout the revolution the gain is so low (below 20 chans/keV) that
	it is not possible to make spectra and light curves from data in 
	this revolution. Therefore a BTI for poor gain determination is 
	declared for the period 8649.4 to 8651.9 IJD.
There is no science data from JEM-X2 for this revoluition.

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: Rating for this revolution:  Very good outside of TOO 
	(within 2--3\%\ of ideal, except for settling zone), bit due to very low 
	gain throughout the entire revolution is declared a BTI from 8649.5 to 8651.7 IJD

JEM-X2: No science data during this revolution

CAO 14/09/2023