Subject: JEMX Monday meeting 2004-07-19


Participants: CAO, SB, NL, and NJW

Status of JEMX units:

   JEM-X2 was reactivated and was active during entire revolution 208
   (ca. 27/6 2004). With temperature correction the gain increased
   in about 10 hours to a level 7% higher than in revolution 170.
   So HV off is not enough to stop wearing completely. JEM-X1 has not
   shown this property (yet?).
   
   A hot spot activity (~5 cts /s) concentrated around anode #203 i.e.
   a full strip was observed for JEM-X2. Anode #203 is counted as a
   dead anode. The hot spot (or hot strip)  has to do with low
   signal events with no backplane signal and completely open rejection
   criteria (for PHA < 115) mean that backplane position (y) is random.
   
   A spectrum in PHA of accepted events shows a sharp turn at PHA=115.
   This is softened in spectra of corrected energies, but we should
   check for its existence. (The ARF will reflect it in any case).
   
FTP link for Instrument Station IPF data:

   The ISDC shift team has not been able to transmit the IPF files from
   the last days. SB is investigating this e.g. by contacting Daniel Rychcik.
   There could be a blockage by the Geneva University network due to
   compromization of data security.
   
Switch off of JEM-X2 DFEE

   This has been suggested since ageing progresses slower at lower temperature.
   It was tried ca. 17/7 2004 for three hours when a temperature drop in
   the IBIS detectors of more then 2 deg was observed. Then the DFEE was
   switched on again. The situation is now being analyzed in more detail
   checking if IBIS functioning is degraded.
   
Various reports

   Peter Kretschmar has come close to finishing editing the Scientific
   Validation Report, Issue 4.
   The inputs to the Observer's Manual (edited by Astri Orr) will be shipped
   very soon (NL and NJW).
   
Upcoming Crab calibration

   We have proposed a 25 point dither with a 5 arcmin step. This was
   discussed at the recent ISWT meeting. IBIS (Pietro Ubertini) is also
   interested in such an exercise, perhaps with larger step such as 40 arcmin.
   Erik Kuulkers will coordinate the Crab calibration. The question is
   not yet settled.
   
AO3 core program

   Proposal: Gal. Cen. and 511 keV latitude scan to get 2.6 Ms
             Scutum/Norma arms to get 1.4 and 0.8 Ms, resp.
             GPS scans: Step increase to 7 deg (still 2200 s and
             sawtooth) - skip when overlap with GCDE, arm survey and
             Crab calibration
             A deep survey observation of an extragalactic field is planned
             (probably around 3C273)
             
Meetings

   Coordination meeting in ISDC 20/9 2004
   ISDC consortium meeting 21-22/9 2004
   SDAST meeting at DSRI 9-10/8 2004
   
AOB - none

/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