Gain Notes for Revolution 179
	
JEM-X1: A quite normal revolution with fine gain smoothing.
All data from this revolution should be useable. 
The first few points in each curve are from the partial switch-on at the
beginning of the revolution, for which HV is set 3 steps below its nominal
value.
All sources show clear fast relaxation due to charging of the plate. This causes
a rapid gain decay after the initial switch on.
Generally low noise and glitch activity. 

JEM-X2: 
The entire period of JEM-X2 activation in this revolution has been designated
a Bad Time Interval for this unit, and ISDC analysis software will disregard
science data from this time period. The BTI is: IJD= 1553.50 to 1553.90.

The otherwise dormant unit was activated for a short time during this
revolution to see how its gain characteristics had changed during the rest
period, and to see how they would evolve on activation. As can be seen the
gain had dropped to something close to its launch values, but recovered this
decrease on activation by increasing rapidly. The short test time was not long
enough for the gain to stabilise, and it became clear that for Crab 
calibrations the unit must be activated well in advance for the data to be
useful for calibration purposes. The first couple of points on each curve show
the partial activation of the unit before switching to the nominal HV value.
Gain fitting is good for this short period, though the steep change in gain,
both visible here on the calibration sources, and to various degrees, and at
various rates across the detector area, means that gain resolution will probably
be worse during this unstable period.

This revolution reprocessed:
0179 : 2005-11-10T03:07:35 j_calib_gain_fitting 7.2



CAO 10/11/2006