Micromegas R&D for ILC and sLHC at Saclay

1. Micromegas R&D for ILC and sLHC at Saclay P. Colas, I. Giomataris, M. Titov

2. Micromegas and other MPGD (Micro-Pattern Gaseous Detectors) are in the process to replace more and more wire chambers in Physics experiments • Robustness, ease of fabrication, rapidity, high rate capabilities,… - Paul Colas - Micromegas R&D

3. Micromegas experiments • The R&D has been lead by several experiments so far: • CAST (low radioactivity, low threshold) • COMPASS (large size, high rate) • NA48/KABES (high rate, 0.6ns time resolution) • T2K (10 m2, 80 kchannels, bulk technology) • Now ILC and sLHC require larger scale and more R&D - Paul Colas - Micromegas R&D

4. The “bulk” technology • Fruit of a CERN-Saclay collaboration (2004) • Mesh fixed by the pillars themselves : • No frame needed : fully efficient surface • Very robust : closed for > 20 µ dust • Possibility to transfer to industry for large size production • Possibility to fragment the mesh (e.g. in bands) • - gives one more coordinate • - lower the capacitance (noise, damage from sparks) • - makes it repairable • Used by the T2K TPC under construction (starts in 2009 in Tokai) - Paul Colas - Micromegas R&D

5. The T2K TPC has been tested successfully at CERN (9/2007) 36x34 cm2 1728 pads Pad pitch 6.9x9 mm2 Saclay’s AFTER-chip based electronics used by Micromegas ILC-TPC Strong synergy between T2K and ILC TPCs. - Paul Colas - Micromegas R&D

6. R&D on resistive anode Carleton-Orsay-Saclay collaboration since 2002. Avalanche size ~12µ in Micromegas, whereas ideal pad size 2-3 mm for 2-track separation with minimal number of electronic channels (cost, power consumption, matter, space) Need to spread the charge to make a barycenter M. Dixit et al. : use a resistive coverlay to make a RC continuous network on the anode surface. Ongoing work at Neuchatel and CERN : use of photovoltaic techniques and screen printing techniques. Large R&D project. No res. f. Q (r,t) integral over pads res. f. ns - Paul Colas - Micromegas R&D

7. R&D on resistive anode Tested at DESY in a 5T magnet (Nov. 2007) : 50 µ resolution at all drifts! Extrapolates to <80µ at ILC (beyond initial requirements) Further advantage: spark suppression and electronic protection Simulations in progress to optimize spreading and protection (E. Delagnes, S. Turnbull) Data from at TPC prototype with 2mm pads gas resistive insulator 25 AFTER Preamps - Paul Colas - Micromegas R&D

8. 55 mm m μ 14080 m (pixel array) 55 16120 m 4 4 55 mm 2 2 3 3 1 1 5 5 55 μ m 14111 m R&D on pixel readout Alternative to obtain ultimate resolution: have small pads (pixels) matching the avalanche size. Then detect individual electrons. CERN-Nikhef-Saclay collaboration within EUDET. Use the TimePix chip (evolution from MediPix) Pixel Synchronization Logic Interface THL disc. Configuration latches Preamp/shaper Counter - Paul Colas - Micromegas R&D

9. R&D on pixel readout Application: study gain fluctuations (bad for resolution and for single-electron efficiency) vs gas and geometry. Access directly Fano fluctuations and ionisation fluctuations. - Paul Colas - Micromegas R&D

10. R&D on pixel readout Provides ultimate resolution possible with a gas Developments within FP7, self-triggering, zero suppression, higher speed Future: communicating chips, architecture to get around dead chips, 3D technology for more robustness,… InGrid technology: deposit the mesh by post-processing on the chip (U. Twente) - Paul Colas - Micromegas R&D

11. The Large Prototype State-of-the art cosmic-ray trigger system MPPC (Si-PM) via KEK Temperature control by Peltier devices and thermistors Field cage by DESY PC-MAG magnet from KEK at DESY (EUDET) Logic by FPGAs - Paul Colas - Micromegas R&D

12. The Large Prototype 7 interchangeable modules 24 rows x 72 pads Av. pad size ~ 3.2x7 mm2 - Paul Colas - Micromegas R&D

13. Micromegas with TimePix EUDET - Paul Colas - Micromegas R&D

14. ATLAS: average single count rates for L=1034 cm-2s-1 J. Wotschak et al. - Paul Colas - Micromegas R&D

15. Muon chambers for a sLHC detector R&D starting to develop large detectors to be used both for triggering and precise tracking at high rate. Strips + segmented mesh will be needed Resistive coverlay will be necessary for good resolution and fewer electronic channels, and for spark suppression P. Llengo, J. Wotschak et al. - Paul Colas - Micromegas R&D

16. Muon chambers for a sLHC detector Large collaboration setting up around ATLAS for this: Arizona, Athens (U, NTU, Demokritos), Brookhaven, Bucharest, CERN, Harvard, Naples, Saclay , Seattle, U. of Science and Technology of China, South Carolina, St. Peterburg, Thessaloniki Test beam in Nov. 2007 - Paul Colas - Micromegas R&D

17. Saclay is involved in EUDET (European FP6), preparation of DevDet (European FP7), RD51 MPGD collaboration (M. Titov co-spokesman, I. Giomataris in Advisory Board, PC convener of ‘Techniques’ working group) • We commit part of our time (I. Giomataris, M. Titov, PC) in organizing conferences (IEEE/NSS, TPC Paris conferences, next RD51 workshop(s), TPC analysis jamborees, ICHEP 2010…). This way we are in permanent close contact with the world-wide MPGD community. Hawaii 2007 - Paul Colas - Micromegas R&D

18. Conclusion • ILC and sLHC now structure the Micromegas R&D, joining CAST, COMPASS, NA48/KABES, T2K • A large TPC prototype is being built and will be operated at DESY and CERN in the next years. • Saclay is interested in the development of Large Micromegas muon chambers for the sLHC upgrade. - Paul Colas - Micromegas R&D