Gain Notes for Revolution 1174

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.
 

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 acceptable gain
correction with all science windows having a Xe level 
within 3-4% of the ideal, though the vast majority are within 1-2%. This
revolution shows a high level of scatter, and the absence os Cu and Mo lines
indicate a high level of uncorrected spatial gain variation.
 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 excellent gain
correction for the first half of the revolution with all except the very 
first science windows having a Xe level 
within 1-2% of the ideal, as usual. However, the last half of the revolution shows
a great deal of scatter in the Xe line with large fitted widths. This is probably
due to the onset of solar activity due to which the revolution was cut short and the
instruments put into SAFE mode. The spectral data from this part of the revolution 
should be used only with extreme caution. As usual, it is also
recommended that users
avoid the first few science windows for energy-sensitive applications.

CAO 20/06/2012