Subject: JEMX Monday Meeting 2004-08-23

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

JEMX instrument status:
      JEMX1 behaves as usual. CBJ: Earlier background variation has
      been shown to correlated nicely with results from the GOES satellite.
      Scattered electrons are probably the source.
      
      Can we wait with HV reduction till after the Crab calibration?
      Then we can study the influence on the spectrum of the high gain.
      
      IPF data transfer works, Instrument Station is stable again.
      
      The switch off of JEMX2 DFEE - to lower the temperature and hence
      slow down the ageing effect - will be tried again soon. The effect
      on the energy resolution must be measured. The gain is expected to
      drop by ~3%.
      
      The lin6 pc problem is not solved yet. We'll try to temporarily
      move to `swarm1' that is not used intensively right now.
      
Crab calibration: will be carried out 27-30/9 2004, rev. 239.
      5x5 dither pattern with steps of 40, 80, and 120 arcmin. On top
      of that a semicircle will be covered of radius 4 deg. Also an arc
      with radius 10 deg will be done but that is outside JEMX FOV.
      
j_cor_position and pixel shift: NJW: By analyzing the collimator shadows
      from pointings with the Crab 2 deg off axis it appears that the
      old combination of CORX/Y and j_cor_position gives position results
      that are less than 1 mm off.
      Further analysis will be made to produce new CORX/Y, PLLX/Y of the
      IMOD IC data that will match the new j_cor_position. The change of
      these arrays is merely a translation.
      
JEMXIROS and midisky: NL: approaching ISDC compatibility. C structures
      have been introduced for `Coding and Testing Standards' compliance.
      Speed has also improved. "midi_b9" is the soon-to-come version.
      
ISDC activities: JC will go there 6/9 2004 - also to install mosaic_weight
      on the ISDC system tgether with Peter Kretschmar.
      
/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