Gain Notes for Revolution 1406

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 subject to strong gain suppression due to solar activity during
the middle of the revolution. This means that despite careful correction for the suppression
to produce good event-by-event gain determination, that spectra may look odd since the
low gain will have lost many low energy events to the onboard low end rejection. 
 

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 good gain
correction with all SCWs, except the very first science windows, having a Xe level 
within 3-4% of the ideal. This is actually a fantastic result given the enormous 
gain suppression in the middle of the revolution
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.


CAO 26/5/2014

JEM-X2: 

The Xe line analysis performed using the IC table shows good gain
correction with all 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.
The same comments apply as for JEM-X1. Despite the IC tables correcting for the
strong gain suppression in a purely event-by-event energy correction, there will be
unusual loss of real events to the low energy discriminator that usually filters out
perticle events, but will have taken many fo the low energy x-ray events. This 
means that spectral will be unreliable, especially at the low energies.

Note that calibration source 4 is no longer used for this unit.

CAO 2/6/2014