Gain Notes for Revolution 1987

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: Excellent for 1st 75% of revolutions (within 2% of ideal) 
	but last 25% has a 'good' rating due to noise caused by grey filtering 
	of the strong source in the FOV (within 4% of ideal)

JEM-X2:Exemplary for first 75% of revolutions (within about 1% of ideal) but this 
	drops to 'acceptable' (within 4-5% )of ideal) for the last part where there is 
	strong grey filtering. This cannot be improved due to lack of good calibration data.

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 28/08/2018