Gain Notes for Revolution 1556

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.

NB: This revolution is heavily affected by the flaring of black hole V404 Cygni which
caused strong greyfiltering in some science windows and the loss of much of the
calibration data during these flares, with subsequent worsening of both the calibration
spectra and the Xe line determination for calibration verification.
 

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: 

The Xe line analysis performed using the IC table shows poor gain
correction with most of the science windows having a Xe level 
within about 5% of the ideal, where the Xe line can be determined at all. 
There are many strong outliers indicating lack of any peok to fit, as well
as possible rapid gain changes (suppression) due to the high countrates
during flares.
As usual, it is recommended that users avoid the first few science 
windows for energy-sensitive applications (automatically removed by OSA 10.0).


JEM-X2: 

Identical comments to those for unit 1.

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 13/7/2015