Gain Notes for Revolution 1114

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: The beginning of this revolution was strongly affected by solar activity that
began in revolution 1113, consequently the first part of this revolution, upto
IJD = 4349.1 is a BTI and scientific data before this time will be ignored by the
standard OSA pipeline. While it has been possible to correct the energy values
within this BTI quite satisfactorily with the IC table, 
it is almost certain that other quantities, notably fluxes, will not be reliable.
 

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 surprisingly good gain
correction with all except a couple outlying science windows having a Xe level 
within 2-3% of the ideal in the non-BTI time range. 
Even within the BTI part of the revolution (upto IJD 4349.1) gain correction is
acceptable, though fluxes and other quantities probably are not. The usual 
warning about settling periods at the beginning of the revolution has in this
case been enforced by the creation of the BTI.

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. The data sometimes looks useable, but only in short periods, because
of the unstable behaviour of the broken anode strip. For this reason the
source 4 data is always discarded.



JEM-X2: 

The Xe line analysis performed using the IC table shows excellent gain
correction aftaer the BTI period, with all science windows having a Xe level 
within 2-3% of the ideal, and most within 2%. As with JEM-X1, the first part
of the revolution is out-of-bounds due to the effect of solar activity.

CAO 28/02/2012