
* JEM-X status
==============

- JMX1 nominal
- Gain change caused by change of conductivity due to
  drift of ions when HV is on. Effect is temperature
  dependent. Negative side effects:
  + loss of spectral rersolution
  + change of spatial gain variations
  + gain depends stronger on intensity (high intensity->local gain drop)
- JMX2 energy resolution 9% -> ~14%
- JMX2 short activation (6h) showed recovered plate, comparable to
  orbit 30, but very rapid 'aging', i.e. increased gain to in-use
  levels. But energy resolution might be improved (~11%).
- Hope for longer activation during next SPI annealing.  
- Gain glitch dips in JMX2 have become more frequent and deeper
  (comparison of rev 30 vs 150). In orbit 30 ~75% of time was on
  normal gain, in orbit 150 it's <30%!
- JEM-X FM1 in lab is worse - gain goes up by factor 5.
- All microstrip plates have maximum intensity above which they
  will be "quenched". Rates in instrument:
  + 50 keV/s/mm^2    Cal. sources
  + 1.5 keV/s/mm^2   CRs in space
  + <0.1 keV/s/mm^2  X-ray sources
- Up to now it seems that calibration source spectra are still
  representative of the overall gain evolution.
- Findings:
  No concern (anymore):
  + anode strip losses
  + gas contamination
  + pressure loss
  Micro-strip plate aging IS a concern
- Should keep "one JEM-X only" policy
- Xe line has to be monitored. Propose to use all-detector spectrum
  and fit Xe line to see if it is OK.


=> Create detector spectra for all survey & CP data.


OSA development
===============
- some HK parameters should go into gain history tables as well.
- New j_cor_gain and _position
- New scripts, possibly new j_bin_bkg_***
- New j_src_spectra and _lc
- New j_bkg_spat_sel, new BKG models for JMX2 ready in testing by NJW
- New j_ima_tools
- New responses, will have to be redone with j_src_spectra-4.0.0
- NJW can't easily find VERSION numbers for JEM-X files.


Documentation
=============

- CAO points out her various pages which seem underused
- ADD wil need update in May/June timerange.


ISDC Rotation
=============

Rotation will be kept, should be aligned with GCDE and interesting
parts of GPS. Regular topic on DSRI monday meetings.


JEM-X and ISOC
==============
- JEM-X 2 should be switched on as long as possible in next
  activation, 40 ksec is definitely not enough.
- JEM-X team needs confirmation when configuration changes are actually
  implemented.
- A. Orr gave overview of her duties. Partially taking over from R. Much.

XE line modelling
=================
- Xe line after reactivation of JMX1 in Apr 04 matches very well
  that of Feb 03.

Bkg modelling
=============
- Sami finds Xe line variations from 29-33 keV in rev 41 data.
- Spectra should have changed significantly after rev 170,
  not yet analyzed.
- Weak source reported in ATEL 223 also not found with bkg
  corrections.
- For GRS 1915+105 there is a slight improvement in DETSIG.
  Somewhat smoother noise pattern.
- Also results for Cen X-3 slightly improved.


Imaging
=======

NJW has developed j_ima_refined_imaging, but needs 9 min per image.

NL explained his midisky, among other points:
- redistribute shadowgram to idealized 1*1 mm grid
- IROS mechanism using pixel illumination  function catering for:
  + mask, mask support, collimator
- Backprojection by "image response"
- emphasized problems of extended footpoints
- PIFs per energy band, digitized to 256 steps (zero to parametrized
  max. illumination.
- In source removal, positions are refined up to 4 times.

- Some discussion about pixel corrections.
- Actual PIF calculation requires both PHA and PI (photon energy)


PC working on jemiros (midisky) [should be named j_ima_iros]
Wrapper around midisky.

Went on explaining his separate work.
...


Spectral extraction using PIFs
==============================

NP would like to use GEANT to create PIFs.

Has generic function regress.C once event data and PIFs
have been read in and events summed to "shadowgrams".
Calculates (no fit) linear solution to flux over PIF value
in shadowgrams => slope is source flux, zero offset=bkg.
Shadowgrams must be corrected for efficiency, and
have flatg bkg in his scheme


Spectral extraction SL
=====================
Calculates PIF at 8 different energies internally
then uses PIF values making cut at 75% as maximum
PIF values vary with energy.

With latest j_src_spectra and Crab: 
  PL=2.12+-0.03, N_H=(1.4+-0.5)E22


NL
==

In 5*5 pattern, one line of pointing positions has 
~10% higher flux than others! Why???

CBJ
===

With own simple analysis got jumps in Crab lc.
If assumes collimator is tilted by 8', this could be explained.


PIF Calculation
===============

j_src_pif  by end of June [SL]
   Creates 1 PIF per source and energy band including vignetting,
   pixel sizes etc.

j_src_spectra by end of June [PK]
   Uses PIF and event lists, applies deadtime, grey filter, GTIs ...
   Interpolates between PIFs calculated for closest energy bands.

j_src_lc by end of July [PK]

Pixel corners go to IMOD table.


Shared Library
==============

Naming scheme: JEMXtypeofdataAction, e.g., JEMXeventsRead

PK will propose C struct for events and read/write functions.
Dito for spectra.

SL will propose C struct and functions for lightcurves.

NJW will propose C struct and functions for detector maps and
images.


Test Cases
==========


Which property		What data	Who	       S/W

lc stability		Crab            SL,CBJ,NL      ISDC,CBJ,NL

image flux stability    Crab            NJW,CBJ,NL     ISDC,CBJ,NL

spectral shape          Crab            SL,PK          ISDC,CBJ
spectral limts		X-ray burster   SB

bkg inclusion           weak            SaM, PK	       ISDC

timing                  Crab            SB,SL          ISDC

misalignment            GCDE+Crab+Vela  NL,NJW	       ISDC,NL

detection sensitivity   

coding noise from       GRS 1915+105    JC,NJW
strong source           & IGR J19140
