Gain Notes for Revolution 1086

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 where something rather odd happens: a strange, sudden and 
long-lasting dip appears in the all the calibration sources that has not relation
to any known temperature change in the instruments. Using this IC table the effects
of this unknown activity can be smoothed out from the gain determination and
energy correction, but there is no garantee that source fluxes and other properties
won't be affected during this period.
 

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 excellent gain
correction with almost all science windows having a Xe level 
within 1-2% of the ideal. As usual however, it is recommended that users
avoid the first few science windows for energy-sensitive applications, and are
cautious about over-interpreting anything strange that happens towards the
end of the revolution where the unexplained gain dip occurs.


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 okay gain
correction with all science windows having a Xe level 
within 2-3% of the ideal. It was not possible to smooth out the residual
signal due to the strange gain dip in this unit as it was in JEM-X1, but the
IC table still brings all science windows within a reasonable energy correction.
As usual however, it is recommended that users
avoid the first few science windows for energy-sensitive applications.

CAO 12/10/2011