From settles@mppmu.mpg.de Fri Jul 13 17:11:48 2007 Date: Fri, 13 Jul 2007 17:11:10 +0200 (CEST) From: Ronald Dean Settles To: lctpc@desy.de Subject: Summary WP#34 meeting 11.07.2007 Dear lctpc friends, Here is a summary of Wednesday's meeting. Let me know if there is something to change/add... Cheers, Ron WP#34 11/07/2007 -------------------------------------------- Wednesday 11 July 2007 West Coast East Coast W.Europe Japan 07.00 10.00 16.00 23.00 Present: --Paul Colas --Katsumasa Ikematsu --Akimasa Ishikawa --Leif Joennson --Sasha Kaukher --Dan Peterson --Oliver Schaefer --Franck Senee --Ron Settles --Jan Timmermans --anybody forgotten? Summary -------------------- 1. Cosmic trigger Relevant drawings/sketches have been attached to recent emails; if you don't have them, they can be clicked at http://www.mppmu.mpg.de/~settles/tpc/lp/wpmtg/wpmtg.html at the bottom, next to "34th: LP meeting" Klaus Dehmelt sent a drawing for the trigger with T2K slabs arranged above and below PCMAG to simulate radial tracks; Dean commented that the counters below should be lower, to get more-nearly radial triggers. (Klaus has had a meeting with SiLC people but has not responded yet since he is at a conference, which will be followed by vacation.) Paul looked into an alternate company for the phototubes and concluded that the T2K solution with MPPC is the best. Email exchanges by Takeshi and Paul after the meeting led to the following changes in: --Responsibilities: 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. 2. LP1 fieldcage/endplate. a. Not much has happened, the latest can be seen at http://w4.lns.cornell.edu/~dpp/linear_collider/LargePrototype.html. Dan has added the weight of the endplate which has been estimated on request of Klaus: 16kg. This could be reduced to 10kg by thinning the areas where there is no panel. Dan said the next step is to make a call for tenders. There are still some decisions outstanding (see 2b. below), but they will not affect a candidate vendor's cost estimate. Reminder: the status from the last meetings: ---magnet inner bore 850mm ID --SiLC detectors (see phonemeeting #27) 35mm on radius --clearance inside of SiLC 780mm --extra clearance (see phonemeeting #27) 5mm on radius --OD of field cage 770mm --field cage wall 25mm --ID of field cage 720mm --module insertion clearance to field cage 3mm on radius --"stay clear" diameter 714mm --40 bolts, 6mm x 1mm, with bolts in the vertical and horizontal positions and 4 pin positions in the field cage. b. From this and last meeting, other design parameters on which we must agree are (points with * are new): 0)*endcap-weight tolerance, 1) bolt circle radius for the 40 M6 bolts (this is 376mm in the drawing shown on the web page), 2) whether the o-ring groove placed in the field cage flange of in the endplate, 3) o-ring size and radial location (this is a 4mm grove, with IR=365mm, in the drawing on the web page), 4) location of the first field shaping band (this 35mm, to the edge of the first band, in the drawing on the web page), 5) location of the field shaping band that defines the end of the drift field (this determines the step in the endplate), 6)*endcap-flatness specs, including "skirt" (drift-field termination surfaces-probably made of copper sheet-for areas where there is no panel), c. Other matters: 7) gas seal overpressure: 2mbar, 8) gas seal test should be made in a G-10 field cage flange, 9) stress-relief tests done: analysis in progress, 10) cable supports: brackets to be included, 11) gas inlet/outlet: TBD, 12) temperature stability/cooling: tolerance TBD. Related to points 6) and 7), Dan said he 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). (Note added by RS: this should be included in Peter Schade's electrostatic simulations, to see if this is good enough.) 3a. Sasha circulated a new connector-layout proposal for LP1, which he adjusted be compatible for either 1mmx4mm or 1.17mmx5.0mm pads. Akimasa etal and Leif etal will study this proposal and give their feedback. Leif pointed out that the inner-layer trace-routing between pads and connectors must be carefully considered. As said last meeting, a mock-up should be made to test any layout. 3b. Sasha asked Leif about purchasing the connectors; in the discussion that followed, it seems they are a bit cheaper in Japan (300 Yen compared to 3+ Euro in Europe), so it would be logical to purchase them there. 4. A.O.B. Next meeting: LCTPC-Electronics/Advanced-Endcap: 25 or 26.07.2007 (to be announced)