Subject: JEMX Monday Meeting 2004-11-15

Present: CBJ, JC, NL, ILR, CAO, NJW

JEMX status: Due to the rather long period of switch-off because of high
       radiation conditions, it took several hours for the gain to
       stabilize. The background level is still high, else JEMX is OK.
        
Preparations for SDAST meeting: CBJ will cover gain development, ageing
       and temperature change. JC will update the anode status. For the
       rest see the agenda.
       
Engineering test on V_c during future OMC flatfield observation: The condition
       of the gas can be monitored by following the gain as a function
       of VC (drift voltage). NL proposes to avoid voltage increase and
       only look at results from lowering the voltage for safety reasons.
       During such a test the FRSS events will be channeled to the science
       data stream.
       
Fast countrate patch: ILR: It has been tested on the FM1 lab model and after
       a few adjustments it seems to work fine. During normal counting rates
       there is no extra time spent for this branch; at peak count rates when
       several buffer losses have been detected it is activated but
       it has not yet been measured what this costs in increased deadtime.
       
Data analysis: NL is working on how to eliminate the non-uniformities
       in the shadowgrams such as the footprints of the amplifiers.
       We may propose for the next Crab calibration to move around in
       steps 3 arcmin apart so that the entire detector will be illuminated
       with real X-ray events. This pattern must be designed with as few
       pointings as possible.
       
End of meeting.

/NJW
       
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Niels J. Westergaard
Danish Space Research Institute
Juliane Maries Vej 30, DK 2100 Copenhagen O
Phone: +45 35 32 57 05; FAX:  +45 35 36 24 75