Gain Notes for Revolution 1026

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.

Something rather strange happened in the middle of this revolution where there was a 
sudden rise in the positions of most of the calibration sources, as though the instruments
had be turned off for a couple of hours. Also the Xe line, found with the original
ISDC NRT Gain History table dropped below 27keV for all but the last part of the
revolution for JEM-X1, and JEM-X2 showed a varying levels of too-low Xe line throughout.
The IC tables provided correct for all these problems, but the very large number of
science windows produce unusually large scatter on the Xe results which cannot be
improved upon.
 

To get optimal results with this revolution it is necessary to use the IC gain history
table that has been created offline at DNSC, instead of the gain history table
created automatically by OSA. If you have the newest package of IC files from ISDC
and these are correctly installed, OSA will find the IC gain history table automatically
and you don't need to do anything else. The updated ISDC Instrument Characteristics
can be downloaded from
http://www.isdc.unige.ch/integral/download/osa_sw



However, if you don't have the IC gain table
package from ISDC you can download the table from the gain history archive by
anonymous ftp through the link provided. Download the table to some suitable
subdirectory for your analysis, then set the hidden OSA parameter gainHist:
gainHist="<my subdirectory>/<IC filename>". These files are used instead of the
automatically generated gain history tables wherever there has been an unusual or
non-linear behaviour of the detector gain.

	
JEM-X1: 

The Xe line analysis performed using the IC table shows okay gain
correction with all except very weak, misfitted, science windows having a Xe level 
within 3-4% of the ideal. As usual however, it is recommended that users
avoid the first few science windows for energy-sensitive applications.


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 acceptable gain
correction with all except one  science window having a Xe level 
within 3% of the ideal. As usual however, it is recommended that users
avoid the first few science windows for energy-sensitive applications.

Something strange happened on the microstrip plate during this revolution
in that all of the calibration sources had a sudden slight jump upwards in
their peak channels without a similar jump being seen in the temperature. The
IC table corrects for this oddity as much as possible.

CAO 05/04/2011