Gain Notes for Revolution 1102

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 is another revolution disrupted by solar activity with significant
gain suppression on both unit microstrip plates, and considerable differential gain
variation (differences in gain behaviour between the heavily irradiated calibration
spectra plate areas and the lightly irradiated science data areas), leading to
large variations in the energy correction during the revolution. The IC tables for
each unit have been able to correct for most of this unwanted gain variation, but a
+/- 5-6% scatter in the data still remains. This is unprecedented in the mission,
but cannot be corrected for at the moment. If better IC correction can be achieved
new tables will be delivered to ISDC.
 

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 poor gain
correction with all science windows having a Xe level 
within5-6% 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 poor gain
correction with all science windows having a Xe level 
within 5-6% of the ideal. As usual however, it is recommended that users
avoid the first few science windows for energy-sensitive applications.

CAO 06/12/2011