Subject: JEM-X Monday Meeting 2006-08-21
Date: Mon, 21 Aug 2006 14:31:16 +0200 (MEST)

Participants: SB, AH, JC, NL, NJW.

JEM-X status (SB): The change of switch-on/off relative to the radiation
belts has given the expected effect. JEM-X works OK.
(JC): Dead anodes status: RAWX=201 is active again but 204 looks suspicious.
Keep a look-out for the edge of the detector (high end of RAWX).

Crab calibration rev 484 (NL): We need to give some input about JEM-X wishes.
We could test if it is possible to keep the HV on (at a minimum level)
during radiation belt passages to avoid the gain change in the beginning
of a revolution.  Now we see a long duration 'undershoot' (couple of hours)
after switch-on after belt exit. Perhaps we could minimize this period.
This exercise can be done performed outside the belt passage.
12 hours (belt passage duration) are required. NL will send a proposal
around. Also an exercize with an anode segment switched off (in
preparation for Sco X-1 observation) to see how the analysis system
handles the data. An idea is to bring the rejection criteria back to
pre-rev170 level.

Short duration occultations of Sco X-1 (NL, SB): Rocks passing in front
of Sco X-1 could give 1-2 ms dips. XTE has observed this. The detector
size of JEM-X is too small for this observation.

Source detection in j_ima_iros (NL): Test with different collimator heights
for the backprojection process. Three cases: full collimator, 6 mm less,
and no collimator. The last case give best source detection for large off-axis
angles. For small off-axis angles the situation is more complicated.

It could be a good idea to compare the j_ima_iros, j_ima_fine_resol,
and CBJ images for sensitivity and flux determination. We must define
a certain SWID with a strong source and a weak source to see the effect
of the IROS process. Taking empty field data and contaminate with Crab
counts could make a useful test data set.

JEM-X catalog (NJW): All public data have been run include IMA level
for the JEM-X catalog for the Moscow Workshop. Various catalog FITS
files are available.

/NJW