Gain Notes for Revolution 1373

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 the first active revolution after autonomous safe mode used
during a solar flare and the instruments start off cold and with very low gain indeed,
possibly caused by continuing high particle flux. This means that the energy correction
for this revolution has be corrected a great deal. Also the huge gain change during
the revolution (about 16 to 26 channels per keV - some of the largest gain variations
ever seen in a single revolution), means that there may be some gain-dependent flux
variations as different numbers of events are trapped by the low-level and high-level
discriminators. Be cautious with this revolution and don't read too much into unusal
activity in the data before consulting with the JEM-X team.
 

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 with all Science Windows, except the very first science windows
and a couple of misfits, having a Xe level 
within about 2% 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 very good gain
correction with all science windows, except the very first science windows and
a possible misfit, 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.

CAO 14/01/2014