Minutes LCTPC WP meeting #108 on July 1st, 2010
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Present:
At DESY: Klaus Dehmelt, Ralf Diener, Takeshi Matsuda, Volker Prahl, 
                Peter Schade, Jan Timmermans
EVO/phonebridge: David Attie, Paul Colas, Michael Lupberger, Keisuke Fujii,
                Jochen Kaminski, Gilles De Lentdecker, Dan Peterson, Uwe Renz, Ron Settles


1) Reminder: next week Tue-Thu ILD software and integration workshop at DESY

2) PCMAG/LPTPC status, testbeam schedule:
- LP idle with gas being flushed
- All motor systems installed and commisioned; Hor. and vert. measuring stick installed;
  a small difference in hor. movement has been observed between moving to the right and
  coming back moving to the left. But we measure the positions now independently!
- We will also be able to measure the position of the LP w.r.t. the magnet.
- Two weeks beam test by Japanese groups in September still foreseen as planned
- The Saclay beam test with one new module will be delayed, from 26 Sept. to mid-Oct.
   as the new module will not be ready in time; on the other hand the Octopus module with 
   8 Timepix/Ingrids is ready, but having some HV problems with 2 out of the 8 Ingrids; will
   try to come to the DESY test beam in Sept. after the Japanese groups.
 

3) Further news from groups:
Saclay - taking data in high-intensity beam at CERN SPS, at the time of the meeting at a rate
             of ~700 Hz muons, but the week after will try to go up to 40 kHz of pions


4) WP5 discussions:
- Ron presented an update on TPC parameters for ILD Integration/Optimization, see his
   slides (that also contain several reminders of slides shown in earlier WP meetings):
   - slides 17/18  discuss again the X0 thickness of endplate/electronics and cables, where
      an educated guess is made of 10% X0 for the power cables, assuming DC-DC 
      conversion. This then totals to 28% in the endcap region, see also next slide 19.
      Remember that the recent study by Mark Thomson showed hardly a difference between
      jet energy resolution in the endcap region when increasing the material budget from 15%
      to 30% of X0.
   - slides 22-28 remind us of the operation parameter differences between the socalled
     'preferred' gas (Ar/CF4/iC4H10 96/3/1%) and the 'backup' gas P5. However sofar
     most of experience at the LP is with  Ar/CF4/iC4H10 95/3/2%, which should give 
     somewhat better quenching than the 'preferred' gas. Paul Colas reminds that having
     from 3.2% iC4H10, makes the mixture explosive.
   - slides 29/30 recall the resolution parametrisations as were used in the LOI large scale
      simulations and the proposed changes for the next round of DBD simulations.
     Need to decide whether the proposed changes are worth the effort.

- Dan presented comments on the CLEO-III drift chamber support and updates on the 
  development of a low material endplate (two slide files attached to agenda page):
   - the CLEO-III drift chamber was supported at 4 points on each side, two upper 
     support points attached to the magnet iron through a support bar and the two lower
     support points attached to the RICH. Ron commented that also the Aleph TPC was 
     supported at 4 points on each side at 90 degree intervals in phi.
   - work on the endplate models is ongoing at 3 levels: the ILD model has been simplified
     to allow it to run successfully in FEA. For the LP1 endplate the FEA model exists, but
     needs some updating. Construction drawings of three different small prototype test beams
     (LP1 type, Al-carbon hybrid and space frame) are completed and price offers will be 
     asked for.
   - Dan expects that funding will continue at the current level.
   - A better computer for the FEA is going to be funded.
   

Next WP meeting #109: July 15th, 2010 14:30 CET

JT