Subject: JEM-X Monday Meeting 2007-01-29
Date: Mon, 29 Jan 2007 14:32:50 +0100 (MET)

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

JEM-X status (SB): Some hotspotting (RAWX=72, RAWY=15), PHA < 50, 50 events/s
when most active. At end of revolution there is an increased background level
lasting about 8 hours (radiation belt entrance). The rate of accepted events
increases with a factor of 2-3.

Michael Schmidt has provided a curve of belt reentrance times and this shows
a seasonal variation (Relative to the INTEGRAL orbit the magnetotail rotates
once per year).

(JC): Anode RAWX=48 has weakened a lot(new dead anode). The one reported
three weeks ago (RAWX=144) has become even less active. Now 30 dead anodes
on JMX1 and 31 on JMX2.

Recent AWG meeting (NL): No final decision on closing neither XMM nor INTEGRAL.
New evaluation in the fall of 2007. No firm expense ceiling should provoke
a closing down of one of the missions.
Publication of interesting articles and ideas for use of INTEGRAL will be
the strongest arguments for a mission prolongation.

Next Crab calibration (NL): XTE and Suzaku have agreed on a coordinated
Crab observation mid-March. ISOC proposes to join to extend the
cross-calibration.

Dead time determination (SB): Time correlation. We never see two consequtive
events with a time-difference less than 180 microsec.
The greyfilter works up-front and is based on a fixed 32-bit pattern for
rejection of events. This means that the 180 microsec deadtime is replaced
by the average time to get a certain number of events. SB will find an
algorithm to predict the deadtime when the greyfilter is active.
A Crab observation with a high value of the greyfilter (can be set 'manually')
could be a good test case for such an algorithm.

Status of ima_iros (NL): Alignment parameters for new version with better
peakfind are under construction - takes some time.

JEM-X observer's manual (all): JC has compared hexagonal dither with and
without change of COP (Center Of Pattern). The noise is reduced significantly
with COP move. This can be investigated in more detail.

/NJW