Gain Notes for Revolution 2689

Despite the TOO observation during this revolution, the
		gain determination is verified throughout, and the gain never
		drops below 20 chans/keV, so no BTI is necessary. 

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 (Xe line positions within about 3\%\ of ideal, 
		except for settling zone)

JEM-X2: No science data for this revolution.

CAO 05/10/2023