Gain Notes for Revolution 1453

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 was affected by automatic switch off and switch on to cover
periods of missing groundstation coverage that happened during renovation of the
Kiruna groundstation. This happened for a number of revolutions contiguous with this one,
and there is a period just after the second, automatic, switch on, where the gain correction
can be expected to be poor, and the data should not be used. OSA 10.0 and later SHOULD
skip over this data for all energy-sensitive applications (such as making spectra) covered
by this period, but users should be aware that this is being done. Expert users can
override the automatic data removal but should also be aware that including this data
may compromise the quality of their spectra, etc.
 

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 for all science windows (taken 2 at a time) having a Xe line 
determination with a realistic width (greater than 2, less than 5/6). These
correctly fitted lines are all within 2% of the ideal, except for the SCWs
immediately after each switch-on (there are 2 in this revolution. So far as
can be determined, the calibration is excellent, except for these settling
periods. Unfortunately, instrument aging makes it very hard to fit the Xe 
lines so that many SCWs are without an individual determination of the Xe 
position.
As usual, it is recommended that users avoid the first few science 
windows after each switch-on, for energy-sensitive applications 
(automatically removed by OSA 10.0).


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 very good gain
correction except during the Bad Time Interval (BTI = 5364.0 to 5364.7 IJD).
All science windows (taken 2 at a time) have a Xe level 
within 2% of the ideal, except for the very first SCWs and those within the
BTI. 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 18/9/2014