Gain Notes for Revolution 1936

N.B. This revolution shows only very weak Xe lines and hence determining the
goodness of the energy determination is rather limited. However, the determination
of the Xe line center for most science windows still lies well within the
energy resolution of the instruments at this point in the mission. SCWs with no
Xe line determination can be assumed to have a determination as good as their
neighbours with a visible Xe line - instrumental gain does not vary significantly
from SCW to SCW except during the initial settling period.

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.
 

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: Very good. Science windows with a realistic fitted width are 
	within 2-3% of the ideal. However many SCWs have no useful
	Xe line determination.

JEM-X2 rating: Excellent. Well-fitted SCWs are within 2% of ideal, but there
	are several complete misfits due to very weak Xe lines.

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 04/04/2018