Subject: JEM-X Monday Meeting 2008-01-23
Date: Thu, 24 Jan 2008 14:00:40 +0100 (MET)

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

JEM-X status (SB): Nothing to report, no special problems.

Crab calibration (SB, NJW): Spectra and XSPEC fits have been shipped to Diego Götz
and we are awaiting further discussions. The flux measured seems to be 10%
on the high side. There is also an (so far) inexplicable difference between
JMX1 and JMX2 where the latter seems to be 15% more efficient. We will continue
investigating this.

Grey filter corrections (SB, NJW, CAO): j_dead_calc derives the DEAD_EFF
column in the JMXi-DEAD-SCP data structure with the new dead time correction
(a consequence of the fixed pattern for events rejection when the grey-filter
is effective). The column RATECOR does not contain this new information,
and it is used by j_ima_shadowgram, hence the better deadtime estimate has
not yet been implemented (it was - erroneously - assumed that RATECOR would
be changed). The new deadtime estimate is introduced in j_ima_shadowgram
rather than in j_dead_calc. Similarly this change must also be implemented
in j_src_spectra and j_src_lc.
On top of this a better averaging procedure in j_ima_shadowgram is introduced.

OSA status (NL): See above. Getting a better electronic efficiency function
for use in j_ima_iros. Three epochs (for JMX1): Revols. 0-38(not considered
since there is no Crab calibration), 39-44, 45-169, 170-inf.
New electronic efficiency tables are derived from j_ima_iros fluxes. They
exhibit a qualitative agreement with the previously derived function from
CBJ flux determinations. Then the use of this function will taken up in
j_ima_iros. 

DTU computing (SB): There are several options in the DTU IT system.

/NJW