Gain Notes for Revolution 2687

There is no science data for JEM-X2 during this revolution
		due to TOO observations of Swift J1727.8-1613 where all TM
		packets were needed to stop JEM-X1 using its grey filter. 
Strong gain suppression due to high particle fluxes only 
		occurs briefly, so the BTI is short: 8661.1 to  8661.4 IJD. 
During the TOO observation there is increased noise in the 
		calibration data, and the Xe line disappears in places, but some
		SCWs with a visible Xe line can be used to determine the general
		goodness of the gain determination, assuming that no significant
		deviations in gain from the general tendancy occur during SCWs with
		no Xe line. Since the Xe line position integrated over the entire
		revolution is close to ideal, it can be assumed that no major deviations
		occurred.

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: Good (within 4% of ideal, except for settling zone
		and misfits with unphysical widths.) 

JEM-X2: No science data for this revolution. 

CAO 21/09/2023