From settles@mppmu.mpg.de Wed Aug 22 08:26:39 2007 Date: Fri, 10 Aug 2007 16:57:02 +0200 (CEST) From: Ronald Dean Settles To: lctpc@desy.de Subject: Summary WP#36 meeting 08.08.2007 Dear lctpc friends, Here is a summary of Wednesday's meeting. Let me know if there is something to change/add... Cheers, Ron WP#36 08/08/2007 -------------------------------------------- Wednesday 8 August 2007 West Coast East Coast W.Europe Japan 07.00 10.00 16.00 23.00 Present: --Ties Behnke --Klaus Dehmelt --Ralf Diener --Michael Hauschild --Dean Karlen --Martin Killenberg --Vincent Lepeltier --Takeshi Matsuda --Dan Peterson --Peter Schade --Oliver Schaefer --Ron Settles --Akira Sugiyama --Jan Timmermans --anybody forgotten? Summary -------------------- 1. Cosmic-trigger-reponsible persons: Basic design: Klaus Scintillator slabs plus light fibres plus MPPC: Takeshi Electronics and power supply: Paul and/or CDC Assembly and Lab test: Sacly/Paul Support and installation at PCMAG: Klaus Schedule: ready beginning 2008. Since it was Klaus' first day back from vacation, he needs time to absorb the many emails that have been exchanged about the trigger counters during the last two weeks before being able to update the set up. He will also be contacting SiLC colleagues about the mounting of their counters. He hopes to be able to summarize the basic design at the next phone meeting in two weeks. Takeshi gave a status report on the counters: he is in contact with Yuri Kudinko about aquiring T2K counters with size adapted to our needs. He will have a phonemeeting with Yuri on 13 August; the length of the paddles for our applications still must be decided. Takeshi has been working on a realistic and not-too-expensive solution for using MPPCs for the signal readout; Ties mentioned another possibility, namely using SiPMs which exist at Desy Calice and could be used. Takeshi and Ties will reslove this option within the next week or so. 2. LP1 fieldcage/endplate. a. Dan has updated several drawings on his web page: http://w4.lns.cornell.edu/~dpp/linear_collider/LargePrototype.html In his words, these 1) update the 3GEM+G backframe specification 2) publish the bounding box drawing and 3) emphasize points about the relative geometry. Some dimensions have been adjusted in the z direction. The size of the panels is still in agreement with the drawings sent earlier to Akira for and Paul. Dan's drawing for the fieldcage has differences wrt Peter's; Peter will mail his version to Dan so that they can converge to one solution. It was decided to put the o-ring groove in the endplate since in case of trouble a new endplate is easier to make than a new fieldcage. For the endplate, Dan has included a "step" which is not in Peter's version, which has a flat endplate. This caused some discussion; Dan included the step for additional stiffness. Dan will try out a version without step and Peter one with step, and the two will try to converge to one option by the next meeting in two weeks. Ties pointed out that there are two apects: thickness for overpressure and thickness to avoid deformation due to machining. Dan reviewed his stress-relief tests which conclude that deformation due to machining can be avoided by: maching cold, first cut 0.75mm oversize, second cut 0.25mm oversize, third cut to size. Dan also reviewed his gas-seal tests: the original leakrate was reduced by a factor of two by redesigning the o-ring groove, and next steps include finding and removing some remaining random leaks. (This is a repeat from last meeting for Peter.) Dan calculated the bowing due to overpressure using the simple analytical formula from an engineering handbook (finite elements are not needed). The result is about 50micrometer deflection at the center for 6mbar overpressure (therefore 3 times less for 2mbar overpressure). This should be included in Peter Schade's electrostatic simulations, to see if 15micron-bowing is tolerable. Ties reported on the fieldcage status. For the mechanics (the cylinder), the company has mastered the basic process and can achieve tolerances and gas-tightness. For the copper-on-kapton-fieldstrip sheet, the other company trying to manufacture it has had problems, and a visit by Ties/Peter last week tried to help solve them. In case of failure, another company in Zuerich has been found that might be able to make the sheet. Finally the resistors for the field-cage have been selected with 0.01 permille tolerance. It was pointed out that heat-treatment might be necessary, since their resistance might be changed by the soldering process. JAE connectors: Leif couldn't join today's meeting but relayed the info the next day by phone that a company has been found in Europe offering cheaper price which is only a factor two more expensive than in Japan. Takeshi has an appointment with the Japanese company on 21 or 28 August to find out the possibilites there. In the meantime, Leif will place a small order in Europe to have some for commissioning since the delivery time is rather long. 3. AOB --Michael reported on a MPGD workshop in CERN on 10-11 September, starting a new R&D project (RD51) initiated by Leszek Ropelewski and Christian Joram for gaseous detectors at ILC and the LHC upgrade. Our LCTPC collaboration should understand its relationship to RD51, which can do R&D useful for our application. Suggestions are welcome. --Jan said that at an appropritate meeting in future, he will summarize ideas towards producing a panel with pixel detectors for LP1. --We should also hear a report from Paul after he is back from vacation. --The merging of LDC and GLD is making progress: the contact persons from the two concepts had a telephone meeting last week and chose a common steering group consisting of 3 GLD and 3 LDC contacts. This steering group will produce and outline of steps leading up to a single LOI produced by GLD-LDC in one year from now. --Next meeting in two weeks: 22.08.2007