Gain Notes for Revolution 1873

This is one of the later revolutions in the mission where the calibration
sources have become so weak that for the best energy determination and
IC Gain History table is needed.
 
N.B. There is a data gap in the middle of this revolution, which therefore contains
only 39 science windows instead of the usual 60 or more. This has in no way affected
the gain determination of this revolution, and energy correction is therefore
exemplary.

To get optimal results with this revolution it is necessary to use the IC gain history.
See notes in revolutions prior to revolution 1433 to find out how to do this
if you don't already know.

All offline gain/energy corrections (including the IC tables) are based on the
two Fe calibration sources in JEM-X1, for both units.

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: Exemplary (Xe line positions within about 1% of ideal)

JEM-X2 rating: Exemplary

The JEM-X2 corrections are based on the JEM-X1 Fe calibration sources, since
all the Cd sources are now to weak to use.

CAO 16/10/2017