Subject: JEMX Monday meeting 2004-08-02

Present: SB, CBJ, JC, CAO, NJW

JEM-X status:  Enhanced (solar) background radiation level in revolutions
      218/219 in particular when INTEGRAL was close to radiation belts.
      IREM recordings 1000 times normal. Now the JEM-X1 background is back
      to about usual level.
      
Energy resolution: SB has measured the JMX2 energy resolution from the Cd
      peak (22 keV) in the FRSS spectra as a function of time.
      
      Relative FWHM ~ sqrt( 0.09^2 + (0.07*(t-t0))^2)
      
      when time 't' is measured in years. The first term is energy
      dependent. The last term could be due to enhanced glitching and
      hence independent of energy - not excluded by the 8 keV Ni lines.
      However, it could also contain an energy dependent part.
      
      For JMX1 the evolution looks different but this could be due to the
      limited operational time. SB will follow the development.
      
GRB in FOV: With an offaxis angle of 5.66 deg for a not very bright burst
      the chances to see it were small. CBJ has made a thourough search
      (isolating events in time and position) but found nothing burst like.
      
ECAL alerts: CAO has investigated the alerts and found that old components
      and IMOD tables were the root of the problem. The executables delivered
      in April would not have issued the alert.
      
NH and low energy spectra problem raised by NL: We need more details in
      order to investigate the problem. The 'curtain effect' in the low
      energy threshold may be of importance. We should see if the actual
      gain is a required parameter.
      
AOB:  SB will go to ISDC Aug. 11 to make necessary updates of the two
      Instrument stations (one in operation and one back-up).
      
/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