Gain Notes for Revolution 218
	
JEM-X1: A quite normal revolution, though very short due to a late switch on.
This occurred due to high solar activity producing lots of high energy protons.
This revolution has fine gain smoothing and  all data from 
this revolution should be useable. 

From End-of-revolution report:
 a) 2004-07-26: due to an unstable radiation environment (dominated by
    proton particles) the OMC and JEM-X units were kept in Safe mode after
    Rad Belts Exit. Still huge solar activity.
 b) The recovery of the OMC and JEM-X1 was completed this afternoon, after
    having monitored the proton & electron fluxes for some hours.
    The re-configuration of JEM-X1 was preceeded by the anode calibration,
    due to the long period  which the unit was left in SAFE mode.
    
The detector line Xe shows clear signs of the gain suppression that occurs
on the microstrip plate at times of high radiation (solar activity). The
calibration areas on the plate do not register this gain suppression presumably
because these areas are already heavily irradiated by the calibration sources
themselves. 

Clearly, from the Xe evolution figure, we can see that the gain suppression
problem is worst just after the switch to data-taking mode, though not
catastrophically so. It is probably best to avoid data taken prior to 
IJD = 1670.0.  This strange behaviour can in no way be linked to changes in
detector temperature, which was stable throughout the data-taking period,
or even changes in the radiation background which remained consistently high 
throughout the orbit.


This revolution reprocessed:
0218 : 2005-11-10T00:30:09 j_calib_gain_fitting 7.2


CAO 4/12/2005