Gain Notes for Revolution 2612

NB: This is a very short revolution with only about 1 day of data. It is also very noisy with extremely weak
instrument background lines which makes it very hard to determine how good the energy determination is. 

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: Acceptable  (Xe line positions within 10% of ideal, except for settling zone and
	numerous misfits of weak or non-existant lines). 
	The extrememly weak background lines, including Xe, make it difficult to determine how good
	the energy determination really is. While the average positionof the Xe line is somewhat
	low, where a Xe line can be determined, these values are within bounds sufficient to identify
	the line with ease in a science window, and correct its position if necessary.

JEM-X2 rating:  also acceptable - same comments as for JEM-X1

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 16/03/2023