Gain Notes for Revolution 1400

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.

This revolution was heavily affected by solar activity which eventually forced the
instruments into safe mode. Strong gain suppression that has not been well corrected
occurred, and therefore much of this revolution is unsuitable for applications requiring
good energy determination. 

 

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 revolution contains a large Bad Time Interval (BTI) for
the period IJD= 5204.0 to 5205.8, for this unit. This is the older, (more used) and
crankier unit, so it's not surprising that this was most strongly affected by the
influx of solar particles.
The Xe line analysis performed using the IC table shows excellent gain correction for
the period after the BTI where all science windows have a Xe level well
within 2% of the ideal. As usual however, it is recommended that users
avoid the first few science windows for energy-sensitive applications. Only
experienced users should use the data within the BTI 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 with all except the very first science windows having a Xe level 
within 2% of the ideal. However there is a short BTI that covers the periods
immediately prior to and after the autonomous switch off.
BTI = 5204.5 to 5205.1 IJD.
As usual however, it is recommended that users
avoid the first few science windows for energy-sensitive applications.


CAO 14/4/2014