From settles@mppmu.mpg.de Fri Oct 5 14:24:28 2007 Date: Fri, 5 Oct 2007 14:24:09 +0200 (CEST) From: Ronald Dean Settles To: lctpc@desy.de Subject: Summary WP#40 LP phonemeeting 04.10.2007 Dear friends, Here is the draft summary of yesterday's WP phonemeeting. Please let me know if you have any changes... Cheers, Ron WP#40 04/10/2007 -------------------------------------------- Wednesday 4 October 2007 West Coast East Coast W.Europe Japan 07.00 10.00 16.00 23.00 Present: --Klaus Dehmelt --Gilles De Lentdecker --Ralph Diener --Xavier Janssen --Katsumasa Ikematsu --Dean Karlen --Dan Peterson --Peter Schade --Ron Settles --Jan Timmermans --anybody forgotten? Summary ----------------------- 0. News -All of our WP meetings now have been documented at http://ilcagenda.linearcollider.org/categoryDisplay.py?categId=26 We will start using ilcagenda for organizing the WP meetings in future. On that website, our follow-up meeting to Eudet in Paris next week (WP#41 10-11 Oct 2007) and the LCTPC collaboration meeting in Fermilab (WP#42 21 Oct 2007) are installed in preliminary form which will be updated as we move closer in time. 1. Cosmic trigger news. -Klaus Dehmelt reported that he will be giving a status report during the Eudet meeting next week, and that discussions with Yuri (IHEP MOscow), Takeshi and Paul are scheduled during the week to iron out the remaining details. After that he will write up a summary to be presented at a future WP meeting (at Fermilab perhaps). 2. LP1 fieldcage/endplate/electronics news. Dan has new technical info/questions on his site: http://w4.lns.cornell.edu/~dpp/linear_collider/LargePrototype.html dated 2007-09-19: -A discussion between Dan and Peter about details the third bullet about the bolt-circle radius indicated that 376 mm is probably o.k. Dan mentioned "self-tapping bushings" might not be the best solution. Helicoils are also a question, since as Dan pointed out they are normally made of metal sensitive to magnetic field, whereas we have said that all LP matierals should be non-magnetic to not spoil with the B-field-map accuracy of 5 x 10^-4. Dan suggested that we make our own (as he has done for CLEO) out of inox, brass, or Si-bronze. (Note added by RS. I enquired what we used in the Aleph TPC: Charlie Ackermann said we used "ENSAT" Buchsen (bushs or bushings, what is the English word?), which are made of brass, see http://www.kerbkonus.com where all possible variations are listed. According to Charlie, after drilling, we tapped the fibreglass, then (as he recalls) applied a thin layer of glue on the outside of the bushing and screwed it into place. That way after the glue hardened the bushing sat absolutely solidly and couldn't loosen.) -RS gave a brief description of how the trapezoidal oring grooves were made in the Aleph TPC. The shape still has to be decided for the LP. -Dan pointed out that the vacuum grease as used for the Aleph orings (as mentioned at an earlier WP meeting) might not be suitable for CF4 which is one of our candidate gases. -Peter reported that the fieldcage materail is still undergoing tests (up to 30kV). The fieldcage will be built by a company (in Bremen?) which will make a madrel onto which the fieldstrip/kapton sheet will be wrapped followed by gluing of a sheet of fibreglass, then the honeycomb structure, then another sheet of fibreglass and finally a sheer of copper. The mandrel can be collapsed mechanically for removal. (On Cleo Dan used air pressure for separation; on TPC90 for Aleph a conical-shaped mandrel was used for slipping it the FC the small end; on the Aleph TPC proper, the mandrel was also collapsed mechnically.) Dan raised the question of the electrical leads into the fieldcage strips from the outside; Peter will look into this and give us the details. -Klaus said that the SiLC colleagues are now planning to start working with us during the cosmics phase in January (earlier we had understood that they would not start until the beam phase around the middle of the year). 3. AOB -Dan pointed out that he and Ralf Diener are both giving talks at ALCPG07 in Fermilab on potentially overlapping material. Those two will get together an make sure that there is not too much overlap. -Next meetings: Paris 10-11 Oct and Fermilab 21 Oct (see point 0. above).