Gain Notes for Revolution 1451

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 affected by an autonomous switch-off, and later a switch-on
which means that it has two separate settling periods. During the second one the
gain correction and energy determination are not nearly as good as for the rest of the
revolution where the instruments are warmed up with their surface and volume charge
distribution stabilized. Therefore there is a BTI (Bad Time Interval) for this revolution,
which covers the period immediately before shutdown, the shutdown itself and a short period
of settling after the switch on. BTI = 5357.9 to 5358.4 IJD.
 

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.

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 3 at a time)outside of the declared
BTI,  having a Xe level well within 2% of the ideal. 
As usual however, it is recommended that users avoid the first few science 
windows for energy-sensitive applications (automatically removed by OSA 10.0 and above).


Calibration source number 4 (purple/orange) is no longer
used for calibration purposes since an anode strip directly under the source
has broken and no useable signal comes from this area of the detector any
longer.



JEM-X2: 

The Xe line analysis performed using the IC table shows poor to very good gain
correction. The first 20 or so SCWs have good gain correction and users should
not read too much into unusual energy values coming from this data. After IJD=5357.1
the gain correction reaches its usual very good level with all SCWs within
2-3% of ideal, taken 3 SCWs at a time.
As usual, it is recommended that users avoid the first few science 
windows for energy-sensitive applications (automatically removed by OSA 10.0).


As with JEM-X1, source 4 is no longer used for energy correction purposes due
to a broken anode strip

CAO 22/9/2014