1. CERN, May 9, 2001P. Colas - TPC, kick-off meeting1 Present and future TPC work at LBL-Orsay-Saclay Principle and advantages of a micromegas TPCPrinciple and advantages of a micromegas TPC AchievementsAchievements Goals and projectsGoals and projects F. Bieser 1, R. Cizeron 2, P. Colas 3, Y. Giomataris 3, J. Jeanjean 2, V. Lepeltier 2, Ph. Rebourgeard 3, M. Ronan 1 (+ many others not mentionned) 1) LBL, 2) LAL Orsay, 3) DAPNIA Saclay

2. CERN, May 9, 2001P. Colas - TPC, kick-off meeting2 ADVANTAGES OF MICROMEGAS Very thin amplification gap (50 to 100  m) => fast signalVery thin amplification gap (50 to 100  m) => fast signal Funnel effect => efficient ion collection ( measurement in progress, see V. Lepeltier’s talk tomorrow )Funnel effect => efficient ion collection ( measurement in progress, see V. Lepeltier’s talk tomorrow ) large gains (10 3 -10 4 )large gains (10 3 -10 4 ) gain independent of the gap to first order => promising dE/dxgain independent of the gap to first order => promising dE/dx easy to build, dead zones potentially very smalleasy to build, dead zones potentially very small potential robustness to agingpotential robustness to aging

3. CERN, May 9, 2001P. Colas - TPC, kick-off meeting3 ACHIEVEMENTS Construction of a small TPC (30 channels, 16cm drift length), HV tests and observation of mesh signals with 55 Fe and 90 Sr sources Measurements of drift velocities with a laser (see case of Ar-CF 4 ) (P.C., A. Delbart, J. Derré, I. Giomataris, F. Jeanneau, V. Lepeltier, I. Papadopoulos, Ph. Rebourgeard, Vienne conf., Jan 2001) Measurement of ion current in progress measurement of aging with Ar-CF4 foreseen several ideas to improve the point resolution

4. CERN, May 9, 2001P. Colas - TPC, kick-off meeting4 STAR ELECTRONICS STAR is a 140 000 channel TPC at RHIC. Started data taking at RHIC in june 2000. Records currently 5000-track eventsSTAR is a 140 000 channel TPC at RHIC. Started data taking at RHIC in june 2000. Records currently 5000-track events A front-end board bears 32 channels with a low- noise amplifier, a shaper, a 5 to 20 MHz Switched Capacitor Array with a depth of 512 buckets and a 10-bit ADCA front-end board bears 32 channels with a low- noise amplifier, a shaper, a 5 to 20 MHz Switched Capacitor Array with a depth of 512 buckets and a 10-bit ADC This is perfectly adapted to the test we have in mind (except polarity)This is perfectly adapted to the test we have in mind (except polarity)

5. CERN, May 9, 2001P. Colas - TPC, kick-off meeting5 STAR ELECTRONICS Mike Ronan helped us to install in Saclay a complete data- taking chain including 20 cards of 32 channels (640 channels) extendable to 1152 channels, in September 2000 and March 2001. FEE MOTHER BOARD DET FIB. OPT VME Pulse generator

6. CERN, May 9, 2001P. Colas - TPC, kick-off meeting6 STAR ELECTRONICS With advice from F. Bieser, we have modified a card to adapt it to both positive and negative polarities, so that we can use it for both a micromegas and a wire TPC. Still to be done: –test a protection against –sparks. –test every channel –design a trigger card

7. CERN, May 9, 2001P. Colas - TPC, kick-off meeting7 PROJECTS Construction of a large TPC (L=0.5m,  =0.35m, 1000 channels) in a 2T magnetic field to work with cosmics. Should be modular (removable endplate, reconnectible electronics) in order to test several schemes. Maybe a smaller chamber to be installed in a test beam to study high rate aspects

8. CERN, May 9, 2001P. Colas - TPC, kick-off meeting8 CONCLUSION We would like to participate in the « federal » effort towards building the best TPC for the linear collider We aknowledge the federative role of a DESY-PRC on this subject More specifically, we would like to study thoroughly, using small setups and a large-scale TPC in a magnetic field, the possibility of using micromegas as an end plate detector We are open to other schemes (including a wire chamber)