Gain Notes for Revolution 2873

Part of this revolution is affected by the presence of a strong
	source in the FOV which depressed the gain and swamped the instrument
	lines so that gain cannot be determined. For this reason the end of the
	revolution is declared a BTI from 9156.8 to 9157.2.

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  (within 2--3\%\ of ideal, except for settling zone,
		a very weak misfitted point with unrealistic width and the BTI) 

JEM-X2 rating:  Very excellent (within  1--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 31/01/2025