Gain Notes for Revolution 1150

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 revolution was affected by solar activity at the beginning of the revolution
and it has been suggested that all data up to 4457.5 IJD be classified as falling
within a BTI (Bad Time Interval) due to poor gain calibration and other disturbances
that may produce unreliable calibration values and poor flux 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 Xe line analysis performed using the IC table shows acceptably good gain
correction with all except about 6 science windows. All SCWs in the second
half of the revolution are within 1-2% of the ideal, with most of the
other SCWs having a Xe level within 3% of the ideal. A handful of SCWs
within the BTI are are only good to 4-5%. There is a great deal of scatter on
the data that cannot be corrected especially in the first 1/3rd of the revolution,
as well as several misfitted outliers. Outliers are all SCWs with a fitted Xe
line width smaller than 2 and greater than 4.
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 very good gain
correction with all except the very first science windows having a Xe level 
within -32% of the ideal. As usual however, it is recommended that users
avoid the first few science windows for energy-sensitive applications.

CAO 23/03/2012