Subject: DSRI JEMX group meeting 040105, minutes

1) Status for JEMX (SB): We've been through several eclipses where gain
   begins very low on the cold detector and increases as satellite warms
   up. This is normal behavior. We still have gain starting at a high level
   and relaxing to a lower level when the HV has been switched off for
   a shorter period - see attached figure and caption at end of this
   mail.
2) New source status (JC) JC will initiate the process of issuing an ATEL
3) Catalog update status (NL) The JEM-X catalog (nl_cat_combine.txt)
   has been updated with SIMBAD positions and includes now 1601 sources.
   The sources that were not recognized in SIMBAD have been rejected.
   The catalog is in /r6/jemx/nlwork/reference/cat_combine_02.txt
   A FITS version will be placed in /r6/jemx/catalogs/cat_combine_02.fits
4 & 5) Source survey and Burst search (NJW & SB) No news
6) Light curves (NL) A procedure to locate the ScWs where a particular
   source is in the FOV and extract a lightcurve across several ScWs
   exists and works well. Unfortunately the lightcurve itself is plagued
   with a bug, so no reliable results are returned (yet).
7) JEMIROS S/W (NL) Paul Connell has delivered (to NL) a version of the
   'midisky' package that is meant to be ISDC compatible. JC will do
   an initial test.
8) Roland Walter's mosaics of NL images (NL). Four (350 MB) FITS files
   exist in /r6/jemx/rolands_mosaics with survey JEMX data (360 deg
   around galactic plane). Interpretation of intensity and deadtime
   corrrection is to be updated.
9) INTEGRAL workshop coming up soon!
10) Upload of patches etc. (NL) No further patches at this time. Request
   for changeover to JEM-X1 has not been discussed with ISOC yet, but
   we think that it is a good idea to make the switch right after the
   Crab calibration in February, 2004.
   
/NJW
   
   
Caption for attached figure:
   The plot shows the gain profiles for JEM-X2 in orbot 41 and 116.
The gain has be normalized to the gain achieved at the end of
each orbit. The zero-point in time has been chosen as the point of
increasing the HV by 3 steps.
Orbit 41 is shown with crosses and orbit 116 is shown with squares.
Both orbits were non-ecclipsing, ensuring a relatively stable 
temperature profile at the beginning of the orbit.
We notice that the gain over-shoot at HV activation has decreased
dramatically over the mission. In fact it seems that the over-shoot 
effect has been overtaken by an under-shoot effect.
However, things are more complicated, as is illustrated by the
gain in orbit 116, where there is a switch-off of the HV after a
few hours caused by radiation. The HV is re-activated after about
1 hour. No data are collected during the brief period of lower
HV setting. In this case we still see a significant over-shoot.
(Søren)

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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

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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