Gain Notes for Revolution 1171

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 affected by strong solar activity that caused and 
autonomous shutdown. The last part of the revolution contains only a short
period of data where
the instruments have not had a chance to settle down after the new switch-on.
Hence this part of the revolution is declared a BTI (BADCONFIGURATION) and should
not be used for applications requiring good gain or flux determination. 
The BTI covers IJD = 4521.0 to 4522.0
In the hours leading up to the autonomous switch off there is a consistent increase
in line widths, indicating a poor energy resolution, which users should be aware of.
 

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 enough gain
correction with all except the very first science windows and some misfitted
outliers having a Xe level 
within 3-4% of the ideal. The Xe line just before the switch off is can be upto 5%
below the ideal, though the large line widths poorer energy resolution greater
uncertainty in the fits, as well as gain suppression caused by increased solar
countrate. As usual, 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 gain
correction for the first part of the revolution, with all except the very 
first science windows and misfitted outliers,  having a Xe level 
within 2-3% of the ideal. 
The second, very short part of the revolution shows a steady downward trend
which is covered by the BTI due to the lack of settling time allowed the
instruments after re-start from the solar flare. 
As usual however, it is recommended that users
avoid the first few science windows for energy-sensitive applications.

CAO 12/06/2012