Gain Notes for Revolution 541
	

JEM-X2: Revolution used to calibration the instruments using Crab observations.
This is the first time JEM-X2 had been activated for 6 months, which
accounts for the long steep increase in gain after switch on. The break seen
midway through the revolution is where calibration exercises were performed
involving changes in the instrument voltages. Prior to this there were other
experiments to determine the effect of turning off one or more of the anode
segments.
The automatically generated gain history table could not be used for two 
reasons: firstly at the very beginning of the revolution there is a short
drop in gain which cannot be fitted by the gain smoothing procedure; secondly,
the missing anode segments during calibration exercises cannot be fitted.

This means that an IC gain history file* must be used to correct this data, and
two Bad Time Intervals have been declared:
IJD = 2634.5 to 2634.8    and     IJD = 2635.7 to 2636.1
A third BTI has also been declared for rapid gain variation and bad response:
IJD = 2634.8 - 2635.2


* The IC file is part of the OSA 7 package or can be downloaded from ISDC
as part of their IC package, it can also be downloaded from the last column of this
table (link "ICgainHistory"), and has name JMX2_gainHistoryIC_rev0541_002.fits
to indicate that it is not the officially delivered IC file. Whichever IC
file you use, it's name should be given in the OSA GUI under the hidden
parameter COR_gainHist :
COR_gainHist = JMX2_gainHistoryIC_rev0541_002.fits[JMX2-GAIN-OCL,1]
If you use OSA with the official IC file package the OSA scripts will find the
correct IC file for you and use this automatically instead of the automatically
generated gain history table that is in the data archive.

CAO 6/06/2007


Xe analysis added to this page is created for the IC table version 2 that takes
into account the new reference calibration channels and brings the Xe line
closer to the 29.6 keV ideal value.

CAO 23/10/2007