Gain Notes for Revolution 2824

Towards the end of this revolution the gain is so low that low energy
		photons are lost onboard by filtering of the low-energy discriminator
		designed to cut out electronic noise from the data stream. Hence
		there is a Bad Time Interval from IJD=9026.4 to 9027.0. OSA automatically
		skips over Science Windows in this period due to BAD_RESPONSE of
		the detectors.
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: Excellent (within about 2% of ideal, except for settling zone,
	a few weak misfitted points during the BTI.
JEM-X2 rating: Very good (within  2--3\%\ of ideal, except for settling zone
		and several weak, misfitted points. The BTI is also excluded
		from this rating. )

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 29/09/2024