Subject: JEM-X Monday Meeting 2006-04-04

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

JEM-X status (SB): Hardware trigger rate. An increase of 60-70% over
the mission (3 years) has been observed. Correlates well with Oulu
neutron monitor rate. The prediction is that the rate will increase
a bit more but we are approaching the turning point in the Solar cycle.
The particle rejection of JEM-X means that the rate of accepted events
has not increased significantly. The deadtime fraction is higher and
this has been taken into account in the data analysis.

No hot spot activity.

Weakened anodes around RAWX=145 for JEM-X2 so the region from
140 thru 150 is dead.

Relaxation period: After long period of OFF then JEM-X2 starts at
gain 60% and it takes 4-5 hours to reach working level.
After normal perigee passage the relaxation time (JEM-X1) is
about 2 hours from 80% gain.

Crab calibration results (CBJ): Circular pattern of pointings around
the Crab Nebula. Lowest gain is 4 steps down in HV, medium gain is
2 steps down. The correction for the electronic efficiency seems
to work well. (When applying the correction from earlier results
the Crab spectrum comes out in a correct way.)
All data from the exercise is in house and further analysis will
be done.

(CAO): The gain correction does not work quite as expected for this
unusual situation; this could be due to a bug in j_cor_gain.

SDAST preparations (all): Two more agenda points: JEM-X status (SB)
and Latest Crab Calibration (CBJ).

/NJW
----------
Niels J. Westergaard
Danish National Space Center
Juliane Maries Vej 30, DK 2100 Copenhagen O
Phone: +45 35325705; FAX:  +45 35362475