Gain Notes for Revolution 1401

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 the second revolution in a row where the instruments were forced into automatic
shutdown by high particle flux from a solar flare. Consequently, the revolution contains
a Bad Time Interval around this shutdown period. During the BTI the gain determination is
not particularly good, and only experienced users should use this data for energy sensitive
applications, such as making spectra. The BTI can be overridden by at user GTI, for example,
to make images and mosaics.The BTI covers: IJD = 5207.0 to 5208.1
 

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 BTI for this unit covers all of the early part of the revolution until the
end of settling after the second switch-on of the instruments.
The BTI covers: IJD = 5207.0 to 5208.1
The Xe line analysis performed using the IC table shows good gain
correction after the BTI, with all science windows having a Xe level 
within 3-4% of the ideal, with the vast majority within 2% of ideal. 


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: 

JEM-X2 shares the same BTI as unit 1.The BTI covers: IJD = 5207.0 to 5208.1
The Xe line analysis performed using the IC table shows excellent gain
correction  for the period 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 the first few science windows for energy-sensitive applications.

CAO 14/4/2014