1. 1 Micromegas TPC R&D P. Colas

2. 2 R&D in progress and to be planned for R&D in progress and to be planned for Present collaborations NIKHEF, CERN workshop, CERN electronics, Carleton, etc… Present collaborations NIKHEF, CERN workshop, CERN electronics, Carleton, etc… Existing and planned infrastructures Existing and planned infrastructures (viewed from Saclay)

3. 3 The context 3 out of 4 ILC detector concepts feature a TPC 3 out of 4 ILC detector concepts feature a TPC All worldwide R&D for ILC TPC is carried out in the framework of LC-TPC (41 institutes, 120 physicists) All worldwide R&D for ILC TPC is carried out in the framework of LC-TPC (41 institutes, 120 physicists) LC-TPC carries out in parallel R&D and common realization of a large prototype LC-TPC carries out in parallel R&D and common realization of a large prototype Mainly GEM and Micromegas technologies are considered Mainly GEM and Micromegas technologies are considered A large Micromegas TPC is being built for the T2K experiment : fully engineered project to be delivered in 2009 A large Micromegas TPC is being built for the T2K experiment : fully engineered project to be delivered in 2009

4. 4 History 1992 Garmich-Partenkirchen proposition of a TPC for the LC (R. Settles) 1996-97 Conceptual Design Report of TESLA. Proposition of Micromegas and GEM readout 1999-2004 TPC Berkeley- Orsay-Saclay June 2005: MP-TPC in a KEK beam 2006 development of the theory of the resolution in a Micropattern detector ; T2K builds a large mM TPC 2002-2005: development of the ‘resistive foil’ at Carleton U. October 2005 : 50 micron at small drift distance in a KEK beam Nov. 2006 : Record resolution: 50 microns at all distances in a 5T field at DESY 2007 towards a collab. for a resistive bulk January-April 2004 : principle demo of gas+pixel (digital TPC) July 2005 : first InGrids (grid on silicon) January 2006 : EUDET start October 2007 first TimePix operational

5. 5 1999-2004 : construction of a large TPC (50cm, 1000 chanels) in a 2T magnet NIM A 535 (2004) 181 Gas studies NIM A (2002), resolution studies Ion backflow suppression NIM A 535 (2004) 226

6. 6 Beam tests at KEK in June and October 2005, cosmic tests in 2006 384 ‘pads partout’ TPC Multi-Prototype TPC (wires, GEM and Micromegas)

7. 7

8. 8 Mesure de résolution à B=0.5 et 1T

9. 9 Analytical theory of the resolution The resolution of a MPGD is limited by ionisation statistics, gain fluctuations and finite pad size effects Given the lack of charge sharing between neighbouring pads, the resolution is, at best, 10% of the pad width 1/√12 1/√(12.N eff )

10. 10 Extrapolation to ILC TPC Conclusion: even with 1mm pads, a standard pad Micromegas would not reach the 130  m resolution goal. However with a resistive foil and 2.3 mm pads, this goal is fulfilled (red curve).

11. 11 Resistive foil A resistive foil glued on the anode turns it into a Resistance and Capacity network which spreads the charge Proc. of LCWS 2005 A 50 microns resolution is obtained at small drift (and at all drifts for B large enough) Test beam at KEK B=1T Micromegas with res.foil Q ns Cosmiques en champ magnétique To appear in NIM A See talk by A. Bellerive

12. 12 Resistive bulk The ‘Bulk’ technology NIM A 560 (2006) 405 yields high robustness with no dead area (no frame) (See R. De Oliveira, I. Giomataris and A. Delbart’s talks) The ‘Bulk’ technology NIM A 560 (2006) 405 yields high robustness with no dead area (no frame) (See R. De Oliveira, I. Giomataris and A. Delbart’s talks) Next step: combine it with the resistive foil technology Next step: combine it with the resistive foil technology Lab tests : resistive bulk manufacturing, resistivity, measurements, uniformity, etc… Lab tests : resistive bulk manufacturing, resistivity, measurements, uniformity, etc… Beam or cosmic tests at CERN and/or TRIUMF or Fermilab Beam or cosmic tests at CERN and/or TRIUMF or Fermilab

13. 13 200  m MESHES Electroformed Chemically etched Wowen PILLARS Deposited by vaporization Laser etching, Plasma etching… Many different technologies have been developped for making meshes (Back-buymers, CERN, 3M-Purdue, Gantois, Twente…) Exist in many metals: nickel, copper, stainless steel, Al,… also gold, titanium, nanocristalline copper are possible. Can be on the mesh (chemical etching) or on the anode (PCB technique with a photoimageable coverlay. Diameter 40 to 400 microns

14. 14 SiTPC Alternative to the resistive foil solution for the problem of the finite pad size: detect ionization electrons one by one on 55 micron pixels Alternative to the resistive foil solution for the problem of the finite pad size: detect ionization electrons one by one on 55 micron pixels Demonstrated in 2004 with Medipix NIM A 540 (2005) 295 Demonstrated in 2004 with Medipix NIM A 540 (2005) 295 Continuation with TimePix (time or TOT recording on each pixel) (see J. Timmermans’s talk) Continuation with TimePix (time or TOT recording on each pixel) (see J. Timmermans’s talk) He 20% iC 4 H 10 Ar 20% iC 4 H 10

15. 15 Medipix2/TimePix at CERN 14.8 mm 65000 pixels on 2cm 2 14 bits counter 10 to 100 MHz clock See M. Campbell’s talk

16. 16 TimePix detector being assembled for - gain fluctuations studies, Fano factor measurement - Study of X-ray polarization Also work in progress at NIKHEF (see Jan Timmermans’s talk)

17. 17 NIKHEF Twente Univ. InGrid : Integrated Grid (post-processing on silicon) Avoids dead areas, allows manufacturing of perfect grids Useful tool to study Micromegas: easy to produce various gaps, hole sizes and gaps,… Allows study of energy resolution, gain fluctuations, ion feedback… (See D. Attié’s talk) NIM A 556 (2006) Energy Resolution ( 55 Fe) 5.0% r.m.s.

18. 18 The “Large Prototype” World-wide collaboration coordinated by LC-TPC (see K. Dehmelt’s talk) World-wide collaboration coordinated by LC-TPC (see K. Dehmelt’s talk) Goal : almost full scale test of various technologies Goal : almost full scale test of various technologies Field cage : DESY Field cage : DESY Electronics : Lund+CERN, (+Saclay for Micromégas) (See L. Musa and P. Baron’s talks) Electronics : Lund+CERN, (+Saclay for Micromégas) (See L. Musa and P. Baron’s talks)

19. 19 The “Large Prototype” endplate Schedule 1st Micromegas panel with 1700 channels ready end of 2007 First cosmic tests in 2008

20. 20 The ideal TPC endplate… Detector side Electronics side Resistive bulk 1000 l.p.i. Nanocrystalline copper mesh, or gold mesh Credit-card-like integrated electronics Low-mass cooling Each yellow item is a R&D topic Res. foil grounding on the side Optical link Mechanical flatness

21. 21 Collaborations All these R&Ds progressed in the past few years thanks to collaborations All these R&Ds progressed in the past few years thanks to collaborations Berkeley-Orsay-Saclay : addressed space resolution issues Berkeley-Orsay-Saclay : addressed space resolution issues Ottawa-Orsay-Saclay : resistive foil effectiveness Ottawa-Orsay-Saclay : resistive foil effectiveness NIKHEF-Twente-CERN-Saclay : CMOS pixel readout demonstration NIKHEF-Twente-CERN-Saclay : CMOS pixel readout demonstration Japan-France-Germany-Canada collaboration: beam test and deep understanding of the resolution Japan-France-Germany-Canada collaboration: beam test and deep understanding of the resolution CERN-Saclay : Bulk technique(s) CERN-Saclay : Bulk technique(s) Also T2K-TPC ND280 is a goal-oriented collaboration which allowed progress, mainly on large volume production and reliability issues Also T2K-TPC ND280 is a goal-oriented collaboration which allowed progress, mainly on large volume production and reliability issues

22. 22 Infrastructures may 2007 Class-1000 clean room UNIGE Laminar flux Many infrastructures are setting up: -Class 10000/100000 Clean rooms at Saclay -2 new R&D labs being equipped for T2K and ILC -1 room equipped with X-ray gun and laser -Lab for gas analysis in Saclay (mass spectrometry, gas chromatography, infrared absorption) -Wafer probing facilities at CERN and NIKHEF -Joint IFAE/Saclay/UNIGE assembly and testing facility at CERN -… Wafer probing at CERN

23. 23 Conclusions Many R&D collaborations and infrastructures exist for Micromegas TPC Many R&D collaborations and infrastructures exist for Micromegas TPC Recognition by CERN is always welcome Recognition by CERN is always welcome Beam tests at CERN will be needed Beam tests at CERN will be needed