From settles@mppmu.mpg.de Thu Jul 11 12:28:10 2002 Date: Thu, 11 Jul 2002 12:21:30 +0200 (CEST) From: Ronald Dean Settles To: LC-TPC@desy.de Subject: Brief summary of TPC Video meeting Friday 5.7.02 Dear TPCR&Ders, As a reminder, the websites where more details are available: http://www.physik.rwth-aachen.de/group/IIIphys/TESLA/TESLA_en.html http://www.lbl.gov/~ronan/docs/lctpc http://www.physics.carleton.ca/~karlen/gem http://www.desy.de/flc/LC/tpc.html http://www.lal.in2p3.fr/recherche/flc http://www-dapnia.cea.fr/Spp/Experiences/FELICE/tpc_micromegas.shtml http://alephwww.mppmu.mpg.de/~settles/tpc/welcome3.html http://www.desy.de/flc/LC/LCdetector.html Below is the short summary... Best wishes, Ron --------------------------------------------------------------- TPC Video meeting Friday 5.7.02, 14:00 Reports from the groups: --Saclay/Orsay *********Paul Colas showed new measurements on test TPCs in the 2T magnet which has recently been commissioned. The ion feedback was measured for micromegas with gain 10^2 using a Sr^90 1GBq source and for a wire version with gain 10^5 using an Fe^55 25 MBq source. The gas was P10. The feedback for the 500lpi micromegas was 2.5% in agreement with MC, and O.4% is predicted by MC for 1000lpi. The MC predicted a 50% increase in feedback from 0 to 2T for the wire chamber which was not confirmed by measurement, and this has to be understood. The construction of a larger micromegas TPC prototype is underway at Saclay and should be ready to go in a few weeks. Paul plans to put his talk on the web when it is ready. --Aachen ****************Sven Lotze discussed again results from the measurements of a 3 Gem structure in a 0-2T field (see http://www.physik.rwth-aachen.de/group/IIIphys/TESLA/TESLA_en.html). There is a suggestion that the increase in extraction and small decrease in collection is because the electrons follow less and less the E-field lines with increasing B-field. --Karlsruhe (and Aachen and Munich) ***************Jochen Kaminski reported that he and Bernhard Ledermann from Karlsruhe and Martin Killenberg from Aachen were in Munich to start setting up the Star electronics. It was decided to buy a dedicated PC as monitor it which will belong to the setup (and move around with it). That will be the place where Mike's account is installed and where all of the software will be put. Martin, Bernhard and Jochen got a monitor to talk to gadwall via at 10baseT port, but gadwall couldn't load in the software because it isn't there yet. We got the 6V power supplies (that belong to the MPI Star group) set up for the RDO board, the FEE boards are there to be hooked up as soon as we are ready. We are missing the fibre-optic link and the trigger/clock unit from Jean-Pierre. (Latest news, that board is now ready but is still being tested.) --Desy ***************Markus explained that the Aleph RO problem was solved by replacing a faulty signal converter. Unfortunately a few days later a spark has since caused problems with the Gems which are being repaired. The hope is to be able to test in the testbeam 1T magnet in about 2 weeks. As for the 5T magnet, it is hoped to be ready in the fall. Interested groups are requested to write a short `expression of interest'. --Carleton ************ Madhu reported that the 200 MHz system should be ready next year to start testing and comparison with simulation. Plans include using a test beam at CERN. As for the resistive-foil idea for spreading the charge and pad-shape studies, Dean (who couldn't attend the video meeting because he was "drifting" to Victoria) showed some of the latest results at the Santa Cruz retreat: here is an excerpt from his e-mail: "...my presentations at the Santa Cruz meeting on the Carleton TPC work is available at: http://www.physics.carleton.ca/~karlen/gem/talks/santacruz02rd.pdf http://www.physics.carleton.ca/~karlen/gem/talks/santacruz02sim.pdf One interesting result shows that chevrons do not offer better resolution than rectangular pads... and that for a Ar CF4 TPC, charge sharing signal provides good resolution, using a 1 cm gap in the final GEM stage for `defocussing'. Perhaps at a future video meeting I could show these results...." --Munich ************The work on the Star electronics was reported by Jochen under "Karlsruhe" above. The drawing for the prototype designed at Munich can soon be found at http://alephwww.mppmu.mpg.de/~settles/tpc/welcome3.html --A.O.B. (1) Who is going to Jeju and plans to give a TPC talk? Markus Hamann asks the question since he is going and will give a talk in the tracking session (M. Winter and H. Park are the conveners). At the video meeting, Paul, Madhu and RS said they are going (RS will not give a TPC talk since he is convener of another WG). So, who else is going...? (2) Groups wishing to make an update for Stefan Roth's TPC presentation at Amsterdam should send him their status report. (3) Ties suggests that the next video meeting be during the 1st week in August on the occasion of Alex Bondar's visit to Desy.