Subject: JEM-X Monday Meeting 2007-01-22
X-Keywords: 

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

JEM-X status (SB): The entrance into the radiation belt happens earlier
than the programmed switch-off. The background level is increasing towards
orbit-end and in a few cases the JEMX instrument has switched-off
autonomously; the greyfilter has also been activated a few times.
SB will send a note to Michael Schmidt on the radiation environment; not
a request for change of operations.

No other remarks on JEM-X performance.

Contribution to deadtime discussion (SB): When greyfilter is active it
looks as if triggers from 17 microsec to 80 microsec after previous
accepted event are missing. We are uncertain about the reason for this.
The revolution 422 is well suited for these studies since the TM allocation
was low for the Crab observations. The deadtime calculation algorithm is
not accurate enough (i.e. below 5%) for these particular cases.

JEM-X observer's manual (NL, all): JC has delivered mosaic_spec spectrum
of burster to Peter Kretschmar. NJW will make an update of continuum
sensitivity and bkg counts. JC will look for public GX 301-2 data for an
Fe line detection example.

j_ima_iros status (NL): Better coordinate system for images implemented
in test version (center of tangent projection shifted to JEMX boresight
in stead of star tracker boresight). This is mostly important for the
invstigations with many observations where the position precision is
required to be better than 10 arcsec.

/NJW