Gain Notes for Revolution 1058

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 instrument background lines are so week throughout this revolution that the
scatter on the Xe line position is very large and science windows must be 
processed 3 at a time to get any reasonable picture of the way the the Xe line
evolves during the revolution. When this is done it is seen that but for
a handful of outliers (misfits with unrealistic widths) the summed data all
falls within 2-3% of the ideal position, which indicates good energy
determination.. 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 the very first science windows having a Xe level 
within 1-2% of the ideal. As usual however, it is recommended that users
avoid the first few science windows for energy-sensitive applications.

CAO 06/07/2011