Subject: JEM-X Monday Meeting 2007-12-19
Date: Thu, 20 Dec 2007 12:12:45 +0100 (MET)

Participants: SB, NL, JC, CAO, CBJ, NJW.

JEM-X status (SB): There is a good deal of background, but JEM-X performance
is fine.

Erik Kuulkers will replace Peter Kretschmar as the JEM-X person at ESAC.

Crab calibration (SB, CAO): IC gain history tables version 2 have been
delivered to ISDC.
We must publish somewhere outside the Cookbook the systematic error to
include in the spectral fit (3%). We must also (re-)investigate the
energy dependency.

Spatial gain map (SB): New spatial gain maps based on the Xe peak
for revolution 245-399 and 399-499 have been derived in single pixel
but smoothed (+-2 in y-direction and +-1 in x-direction).
Clear deviations from original spatial gain
map were noticed. There is an indication that a spatial gain map per
100 revolutions is an appropriate frequency.

Event corrections (CAO): In revolution 175 there are some events
(12 out of 64000 events) should have had PI=255 but have a randomized
value. This turns out to be an overflow problem, an SPR has been
submitted on j_cor_gain.

OSA status (NL): Presented a summary of the flux determination in j_ima_iros
(SRCL-RES). There are some strange changes from one Crab calibration to
the next one. The off-axis behaviour in x and y is similarly difficult
to understand.
Could there be an effect of copper fluorescence induced by strong sources
such as the Crab? NL will look into this.

DETE-MOD investigations (NJW): An update of DETE-MOD is required. An automatic
definition of dead anodes can be defined that seems to work well.
New IMOD epochs covering about 50 revolutions will be defined.
Should we change the flagging in the DETE-MOD detector map to show dead anodes,
neighbors to dead anodes, weak anodes, hyperactive anodes, if the Xe line
can be found in the spectrum from that particular anode (or fraction of anode)?

/NJW