Gain Notes for Revolution 913 JEM-X1
	
Another SPI annealing revolution with very high gain, up to 30 channels
per keV. This brings out the non-linear temperature effect that cannot be
corrected by the automatic software and must therefore be done offline.

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% 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.

The first part of the revolution with the most rapid gain change has been declared a
Bad Time Interval for this unit, and the data during this period will be ignored
by the OSA processing. The BTI is IJD = 3747.3 - 3737.6



CAO 21/05/2010


	Gain Notes for Revolution 913 JEM-X2
	

A quite normal revolution with fine gain fitting, though detector gain
was very high. All the data from 
this revolution should be useable. The Xe line analysis confirms the 
okay gain calibration for this revolution with all the Science
Windows having a Xe line position with 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 26/05/2010