Gain Notes for Revolution 915
	
JEM-X2: A quite normal revolution with fine gain fitting. All the data from 
this revolution should be useable. The Xe line analysis confirms the
okay gain calibration for this revolution with all Science
Windows having a Xe line position with about 2-3% of the ideal value.
 As always, however, it is suggested that
users avoid the first few science windows in each revolution since this is
where the instrument warms up and gain variations across the plate settle down.


CAO 28/04/2010

	Gain Notes for Revolution 915
	
JEM-X1: Another SPI annealing revolution with very high gain that causes
a non-linear effect in the aged JEM-X1 unit that cannot be corrected
automatically.

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. 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.

The Xe line analysis using the IC table confirms the excellent gain correction
that is achieved if this table is used, with gain calibration within 
about 1-2% of the ideal for all
science windows except the first ones. As always it is recommended that the
first few science windows in the revolution are avoided for all applications
requiring accurate energy determination.

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.




CAO 21/05/2010