Subject: JEMX Monday Meeting 2004-06-01

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

1) JEMX status
    JEM-X1 HV was reduced one step in revolution 198

2) Update of JEM-X performance report

   We have two documents to update
   - the Observer's Manual (edited by Astrid Orr) where updates must be
     delivered soon. We have a specific list of questions from AO.
   - the JEMX scientific validation report that must be handed over to
     ISDC (Isabelle Lecoeur) by end of June. A special DSRI meeting will be
     devoted to this, but inputs will be requested from SDAST members.
     
3) Pixel Illumination Function

   CBJ has determined the rotation of the collimator with respect to the
   microstrip pattern to be
         JMX1 :  0.17 deg
         JMX2 :  0.03 deg
   by folding shadowgram data modulo the collimator period (7.06 mm)
   for the Crab at an offaxis angle of 2 deg (to make collimator
   shadows broader)
   
   NL will freeze these in his fitting to get the Crab lightcurve right
   (read constant) across many science windows.
   An update of the 'skymap'matrices is underway but needs more checks
   for bugs.
   
   CBJ remarked that the count rate in the detector area unaffected
   by the collimator could be compared to the total count rate in order
   to find the on-axis throughput. This result can be compared with the
   thicker collimator walls derived from the NL analysis.
   
4) Analysis of Xe line from PK's detector spectra

   JC has looked at the detector spectra extracted by Peter Kretschmar.
   Those spectra were obtained by using ISDC S/W (BIN_S level in the
   pipeline) for a number of arbitrary ScWs, over the whole detector inside
   a radius of 105 mm (default value) and corrected for both spatial and
   gain variations. A semi-automatic tool has been developed to analyse the
   Xenon line energy position
   and resolution. The spectra can be divided in two classes: 1) those for
   which the background is clear and the Xenon line obvious and 2) those
   for which a strong source is inside the FoV and hence the Xenon line is
   much less apparent.
   The analysis tool can find a Xenon line in 94% of the 912 JEM-X1 spectra
   and their average energy position is 30.17 keV (standard error 1.2 keV)
   for an average width of 2.9 keV, that is an average energy resolution of
   9.6%. No temporal trend is found in the position of the Xenon line.
   For the 3698 JEM-X2 spectra, a part corresponding to a period during
   which the HV cut-off was too low has to be excluded from the analysis
   before it is possible to say how much the Xenon line deviates from its
   expected position. This work is proceeding. (Text from JC)

5) ISDC activities
   SM has been at ISDC the last week. NJW will probably go there June 14.

AOB: NL has been at an extra ISWT meeting where the issue of Galactic
   Center observation vis-a-vis Russian time was discussed. Wishes for
   more background observations i.e. extragalactic pointings were also
   presented.
   
/NJW
----------
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






Hej Niels Jørgen,

Her er mit bidrag til JEMX møde referat. Du må gerne klippe/ændre i teksten.

JC has looked at the detector spectra sent by Peter Kretschmar for 3 weeks ago.
Those spectra were obtained by using ISDC S/W (SPE level in the pipeline) for a 
number of arbitrary ScWs, over the whole detector inside a radius of 105 mm 
(default value) and corrected for both spatial and gain variations. A 
semi-automatic tool has been developed to analyse the Xenon line energy position
and resolution. The spectra can be range in two classes: 1) those for which the 
background is clear and the Xenon line obvious and 2) those for which a strong 
source is inside the FoV and where the Xenon line is much weaker.
The analyse tool can find a Xenon line in 94% of the 912 JEM-X1 spectra and 
their average energy position is 30.17 keV (standard error 1.2 keV) for an 
average width of 2.9 keV, that is an average energy resolution og 9.6%. No 
temporal trend is found in the position of the Xenon line.
For the 3698 JEM-X2 spectra, a part corresponding to a period during which the 
HV cut-off was too low has to be withdrawn before it is possible to say how much 
the Xenon line moved from its expected position. This work is proceeding.

Jérôme

-- 
Dr. Jérôme CHENEVEZ                     Dansk Rumforskning Institut
Danish Space Research Institute         Juliane Maries Vej 30
http://www.dsri.dk/~jerome              DK-2100 Copenhagen Ø
Tel. +45 35 32 57 03                    FAX: +45 35 36 24 75