Gain Notes for Revolution 1136

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.
 

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 very good gain
correction for all science windows with a Xe signal strong enough to
be fitted (poorly fitted SCWs are those with a width outside the range
1.5 to 3.5). All the well-fitted Xe lines have a Xe level 
within 2-3% of the ideal. 
Despite a good fit to the strong peak in hardware triggers, it is not possible
to determine the Xe line position in this peak since the grey filter has
kicked in and removed many of the Xe photons from the telemetry chain, making
it impossible to fit reliable line positions to SCWs in this time range.
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 excellent gain
correction with all science windows having a Xe level 
within 2% of the ideal. As usual however, it is recommended that users
avoid the first few science windows for energy-sensitive applications.
NB: Despite the gain dip seen in JEM-X1 due to the peak in trigger rate
JEM-X2 shows no such behaviour at all, and the gain smoothing for the IC
table has actually been done without any trigger dependence.

CAO 1/03/2012