Gain Notes for Revolution 1671

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 contains 2 separate automatic shutdowns and re-activations, which
means there is very little science data in this revolution. However, despite these
disruptions the energy determination is of the same quality as usual, within about 2% of
ideal, and all problems arising from the episodic nature of the data-taking have been
smoothed out by the offline calibration process, which means that so long as users
use the IC gain history tables provided by ISDC there should be no problem using
this data as usual.
 

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 excellent gain
correction with all science windows (taken 1 at a time) having a Xe level 
within 1-2% of the ideal, except for the first settling points. Even the
somewhat weaker settling events in the later two activations do not lead
to a significant worsening of the energy determination. 
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 as for JEM-X1 above.

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 28/04/2016