Gain Notes for Revolution 1190

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.

N.B. The last 2/3 of this revolution were strongly affected by a solar flare that caused
varying degrees of gain suppression all over the microstrip plates of both units - hence the lack
of a clear Mo background line in the instrument line analysis. This means that the last two
thirds of the revolution should not be used for energy sensitive applications - this proviso
includes flux determinations since wild gain changes can cause many events to be lost to
either the high or low energy rejection filters. This period of the revolution is officially
flagged as a BAD_RESPONSE Bad Time Interval, and should only be unflagged by users who
understand the instrument behaviour. The BTI starts at 4576.8 IJD
 

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 for the first third or so of the revolution with all these 
science windows having a Xe level 
within 3% 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 for the first 1/3 of the revolution with all these
science windows having a Xe level 
within 3% of the ideal. The last 2/3 of the revolution are declared a BTI
(see above for details). As usual however, it is recommended that users
avoid the first few science windows for energy-sensitive applications.

CAO 18/07/2012