Subject: JEM-X Monday Meeting 2007-12-10
Date: Mon, 10 Dec 2007 14:05:55 +0100 (MET)

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

JEM-X status (SB): Nothing to report. No hotspot activity. Some radiation
at the end of each revolution. INTEGRAL shifts the nominal radiation belt
to a larger altitude.

For the TM there is a safety buffer that currently is not exploited. An
overbooking in the polling cycle will provoke some use of the extra buffer.
Consequently a few extra packets can be transmitted. This has been run
on the simulator and will probably be tested on the spacecraft soon.

Calibration (SB): The public data up to revolution 496 has been used
to generate a new SPAG (spatial gain map). 6 epochs, each with about
50 revolutions, have been used. The work is ongoing.

A plot of the Xe line per anode (given RAWX value) is an auxiliary
indicator of the degree of life in an anode strip.

The long integration time can also reveal more details of anodes that
are not interrupted at their root but at some distance from it.

Crab calibration (SB, CBJ): The goal is to reach an absolute assessment
of the Crab intensity. A selection of the best area of the detector where
there is little doubt of the efficiency (i.e. no loss in weak anodes).

j_ima_iros status (NL):
Systematic effects:
   - The derived flux changes from one Crab calibration period to the next
         It is not clear why this is so. The cause can be outside OSA.
         There is a step after revol. 45. We must check if there is a
         change of a setting of .e.g. a discriminator.
   - Radius dependence
   - Azimuth dependence

We must make at least one IMOD epoch per Crab calibration in order to ensure
the best detector map for each. This matches well with the 50 revolutions
required for the SPAG generation.

A re-reading of the collimator measurement report reveals that there is
an RMS scatter of lamellae positions (measured at each collimator hole)
of 0.1 mm. This implies that the throughput does not have a pyramid shape
but rather a rounded apex.

/NJW