Gain Notes for Revolution 1339

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 is a revolution during which a large solar flare occurred, so that the first
2/3 of the revolution, or thereabouts, has been declared a Bad Time Interval due to
BAD_RESPONSE, and the data from this BTI should not be used by anyone but experts in 
the JEM-X instruments and data processing. The BTI covers IJD = 5021.5 to 5023.3. During
this period the gain response of the instruments is critically suppressed by the high
particle flux and subsequent plate charging. Also, the autonomous switch-off forced
by the  very high countrate means that there are two periods of substantial gain variation
while the plates came to charge equilibrium after the switch-on of the instruments.
 

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 after the BTI, with all except three misfitted science windows,
 having a Xe level 
within 3% of the ideal. However, gain calibration within the BTI is very
poor, to almost non-existent, and this data should not be used at all for any
energy-dependent 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 after the BTI, with all science windows having a Xe level 
within 2% of the ideal. As usual however, it is recommended that users
avoid using the data within the BTI period.

CAO 14/10/2013