Gain Notes for Revolution 1386

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: Something very odd, neither temperature nor countrate
related, happened to cause a sudden gain suppression on this instrument. However
most of this problem has been cleared up with the use of the IC tables.
 

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 pair of misfitted outliers, having a Xe level 
within about 2% of the ideal. Something very odd, neither temperature nor countrate
related, happened to cause a sudden gain suppression on this instrument. However
most of this problem has been cleared up with the use of the IC tables.
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 reasonable gain
correction with all except the very first science windows having a Xe level 
within 4-5% of the ideal. The strange gain suppression in the last 1/3 or so of
the revolution is not well-corrected for unit 2 the way it is for unit1, and users 
should be wary of over-interpreting energy and spectral data in this part of the 
revolution. As usual it is recommended that users
avoid the first few science windows for energy-sensitive applications.

CAO 23/03/2014