1. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 20081 TPC Review David Attié 10-th INTERNATIONAL CONFERENCE ON INSTRUMENTATION FOR COLLIDING BEAM PHYSICS Novosibirsk, March 1 st, 2008

2. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 20082 Outline 1.The Time Projection Chamber Description Characteristics 2.Examples of TPCs TPCs for High Energy Physics: Particle Physics and ions Physics TPCs for rare event detection: neutrinos, dark matter 3.TPC R&D Readout for TPC: Micro Pattern Gaseous Detector (GEM, Micromegas) Gas studies Spatial resolution measurements and techniques 4.The LC-TPC collaboration The Large Prototype

3. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 20083 TPCs have been operated often as the main tracker in a wide range of physics experiments: –particle physics –heavy ion collision –underground experiments Need for Physics measurements: –momentum resolution –pattern recognition –low material budget to preserve good jet energy resolution Physics knowledge depend on the sensitivity and the performance of the instrument Introduction

4. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 20084 1.The Time Projection Chamber

5. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 20085 TPC description Gas volume Readout z x y gas system field cage for the E field magnet for the B field amplification system at the anode gating grid to suppress the ion feedback laser calibration system readout electronics trigger Ingredients: The TPC is a gas-filled cylindrical chamber with one or two endplates Particle detector invented by D. R. Nygren in 1974

6. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 20086 Track point recorded in 3-D (2-D channels in x-y) x (1-D channel in z = v drift x t drift ) Low occupancy  large track densities possible Particle identification by dE/dx long ionization track, segmented in 100-200 measurements STAR ion TPC BNL-RHIC ALICE simulation events -LBL STAR TPC -at BNL RHIC ion collider Characteristics of a TPC

7. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 20087 2.Examples of TPCs

8. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 20088 Experiments with a TPC TOPAZ (KEK) ALEPH (CERN) DELPHI (CERN) PEP4 (SLAC) STAR (LBL) Some detectors in Particle and ions Physics using a TPC

9. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 20089 Today: ALICE at LHC ALICE (A Large Ion Collider Experiment) search for a quark-gluon plasma in heavy ion collisions Pb-Pb at a centre of mass energy of 5.5 TeV per nucleon

10. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200810 First cosmic-rays events in ALICE TPC 3-dimensional view of a shower induced by cosmic rays L. Musa et al. January 2008

11. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200811 Performance needed for the ILC-TPC LC-TPC should provide a good resolution on the momentum measurement  Precise and model-independent measurement of the Higgs-Mass in the Z  μμ recoil Momentum: σ 1/p ~ 5x10 -5 /GeV(1/10 x LEP) - Z mass reconstruction from charged leptons - Higgs-Strahlung: Need to support high density of tracks and/or final states with 6+ jets: –high granularity –good two tracks separation –track identification e+,μ+e+,μ+ e–,μ–e–,μ–

12. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200812 ILC-TPC simulations Simulation GEANT4 of LC-TPC, A. Vogel TPC for the International Linear Collider, e+e- collisions at 500 GeV Includes beam background

13. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200813 Future TPC for rare events detection Rare events topics: –neutrinos physics (double-beta decay, T2K long baseline experiment) –Dark Matter search, WIMPs, axions TPC medium can also be used as the target Main TPC characteristics for this physics: –a large volume and/or a dense medium: pressurized gas or liquid –a “quiet” TPC (for example, no needs for gating gate) –generally underground experiments with low activity materials Examples : –ICARUS: Imaging Cosmic And Rare Underground Signals –GLACIER: Giant Liquid Argon Charge Imaging ExpeRiment –DRIFT project: Directional Recoil Identification From Tracks –T2K: Tokai to Kamiokande

14. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200814 ICARUS (Imaging Cosmic And Rare Underground Signals) at Gran Sasso the biggest one ever build Observation: - high energy neutrinos (17 GeV) from CERN - solar ν (5-14 MeV) - supernovae ν (10-100 MeV) - atmospheric ν (1GeV) 300t of Liquid Argon (idea from C. Rubbia, 1977): -Argon is not electronegative: electrons may drift over very long distances - many e- are produced (60000/cm for a MIP particle) - + scintillation in Ar (50000 ph./cm for a MIP particle) - Argon is inexpensive (1% in the atmosphere) future: 100kT GLACIER LAr detector? ICARUS for neutrinos Physics

15. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200815 ICARUS for neutrinos Physics

16. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200816 GLACIER TPC Giant Liquid Argon Charge Imaging ExpeRiment (A. Rubbia, hep-ph/0402110) A scalable design: 10 kton Ø = 70 m h = 20 m Passive perlite insulation 100 kton Electronics crates Two phases Argon TPC LEM (Large Electron Multiplier) = thick macroscopic GEM readout, very long drift Single module cryo-tanker based on industrial Liquefied Natural Gas (LNG) technology Could potentially be magnetized

17. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200817 DRIFT (Directional Recoil Identification From Tracks) negative ion TPC (C. Martoff, N. Spooner et al.) the most exotic ! For detection: - WIMP - Axion electronegative gas additive (CS 2 ) captures primary e-  negative ions Excellent background discrimination future: large underground observatory 4m 8m DRIFT for Dark Matter

18. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200818 T2K : Tokai to Kamiokande Long Baseline neutrino experiment with an intense beam (0.75MW) Aiming at  13, and “atmospheric oscillation” measurements 2 detectors: far (SK) and near at 280 m from target Off-axis beam JPARC currently under construction  first beam 2009 The 280 m detector is used to check the initial beam composition, it includes 3 large Micromegas TPCs B = 0.2 T

19. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200819 3.TPC R&D

20. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200820 Plan of TPC R&D Develop the readout technologies –Tests with small prototypes Studies of the gas mixtures –Limit the diffusion –Find a stable state Improve the spatial resolution: resistive or digital anode –Resolution with short drift length is dominated by Readout pad pitch Width of induced charge on pad plane –To decrease pad pitch Digital TPC Increase signal width  Resistive anode pad readout, but two track separation might be less good Built and test a larger prototype to make the technology choice Design and produce the final TPC for the specific experiment

21. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200821 Micromegas & GEMs (MPGD) 50 µm 40 kV/cm ~1000 µm 1 kV/cm GEM ~50 µm 80 kV/cm Micromegas Technology choice for TPC readout: Micro Pattern Gaseous Detector more robust than wires no E×B effect better ageing properties easier to manufacture Avalanche fast signal & high gain low ion backdrift Gas Electron Multiplier (F. Sauli, 1997) 2 copper foils separated by kapton multiplication takes place in holes use of 2 or 3 stages MICROMEsh GAseous Structure (Y. Giomataris et al., 1996) metallic micromesh (typical pitch 50μm) sustained by 50μm pillars, multiplication between anode and mesh, high gain Gas Electron Multiplier (F. Sauli, 1997) 2 copper foils separated by kapton multiplication takes place in holes low gain

22. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200822 Micromegas & GEMs (MPGD) 2- or 3- stage amplification easy operation low field above the electronics low discharge probability simplicity single stage of amplification natural ion feedback suppression discharges non destructive GEM Micromegas Technology choice for TPC readout: Micro Pattern Gaseous Detector more robust than wires no E×B effect better ageing properties easier to manufacture fast signal & high gain low ion backdrift

23. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200823 Bulk Micromegas technology Copper segmented anode Lamination of Vacrel Positioning of Mesh Encapsulation Development FR4 Photo-imageable polyamide film Stainless steel woven mesh Border frame Spacer Contact to Mesh Base Material I. Giomataris et.al., NIM A560 (2006) 405 Process to have an encapsulated mesh on a PCB (mesh = stretched wires) Motivations for using bulk Micromegas –the mesh is held everywhere: no dead space, no frame –robustness because it is closed to dust –can be segmented –repairable

24. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200824 Bulk-Micromegas prototypes of TPC for T2K Geneva-Barcelona test bench Test of a T2K module with a 55 Fe source Micromegas prototypes: Bulk: 34x36 cm 2, 128  m gap 1728 pads of 6.9x9 mm² HARP test at CERN (PS/T9) MM1 detector + FEE + Cooling system HARP solenoid (0.7 T) Field cage 1.5 m drift length Sep. 19 th – Oct. 3 rd 2007 (Analysis in progress) Electronics: AFTER ASIC from Saclay By T2K/TPC-Europe

25. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200825 Bulk-Micromegas prototypes for T2K Signal from 55 Fe source  = 8.5% rms @ 5.9 keV  = ~8% rms @ 5.9 keV Lab Test HARP test at CERN (PS/T9) Energy resolution consistent with lab. test results E = 160 V/cm, B = 0.2 T Source located at 1.54 m from MM detector

26. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200826 Bulk-Micromegas prototypes for T2K 15 GeV/c p-Pb interactions in front of the TPC Cosmic rays in the TPC Y X T Y 55 Fe source HARP test: events display

27. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200827 Ion feedback measurements Gain ~ 200 σ t = 9.5 μm 20 μm pitch p1 = 1.01 32 μm pitch p1 = 0.90 45 μm pitch p1 = 0.96 58 μm pitch p1 = 1.19 BF = p 0 /FR p1 Measurements with a 45 μm gap InGrids Backflow fraction (BF) down to 1 permil at low picth and high field ratio M. Chefdeville et al. IEEE/NSS 2007

28. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200828 Gating for ILC If natural ion backflow suppression is not sufficient, gating can reduce the number ions feeding back in the drift space Time structure: one ms train every 200 ms Gating can be done with wires or a GEM operated at unit gain Wire gating GEM gating Gate Open Gate Closed  50mm/ms - + Previous beam train x-ings

29. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200829 Gas properties studies

30. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200830 Mixtures of gases containing argon: gain curves iC 4 H 10 CO 2, CH 4 C2H6C2H6 Micromegas Mesh : 50  m gap of 10x10 cm² size

31. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200831 Energy resolution vs. gain Argon/Isobutane Best RMS for a gain between 3.10 3 & 6.10 3 Degradation increase in inverse proportion to the quencher

32. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200832 Spatial resolution studies

33. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200833 Spatial resolution: 5 T cosmic-ray test at DESY 5T magnet at DESY + COSMo TPC Resistive anode Micromegas COSMo TPC resistive foil glue pads PCB mesh  (r,t) integral over pads  (r) r (mm) Q(t) t (ns) M.S.Dixit et.al., NIM A518 (2004) 721 COSMo (Carleton Ottawa Saclay Montréal) TPC + 10 x 10 cm² Micromegas (50 μm gap) + resistive anode used to disperse the charge (126 pads of 2x6 mm²size)

34. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200834 Spatial resolution at 0.5T vs. gain B = 0.5 T, resolution fit bywhere N eff number of effective e- Resolution  0 (  at z = 0) ~ 50 µm still good at low gain (will minimize ion feedback) Mean of N eff = 27 Gain = 4700 Gain = 2500 N eff =25.2±2.1 N eff =28.8±2.2   0 = 1/40 of the pad pitch

35. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200835 Spatial resolution at 5T vs. gas mixtures Ar Iso (95:5) B = 5T Ar Iso (95:5) B = 5T 50  m At high magnetic field (5T)   ~ 50 µm independent of the drift distance Dixit, Attié, et al., NIMA 581, 254 (2007) Extrapolate to B = 4T with T2K gas for 2x6 mm² pads: D Tr = 23.3 µm/  cm, N eff ~ 27, 2 m drift distance,  Resolution of  Tr  80  m will be possible !!!

36. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200836 Tsinghua: TPC prototype with GEM Readout

37. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200837 Tsinghua: 1 T cosmic-ray test at KEK Test in Dec. 2007 Preliminary results !

38. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200838 Digital TPC

39. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200839 Chip (CMOS ASIC) upgraded in the EUDET framework from the Medipix chip developed first for medical applications IBM technology 0.25 µm Characteristics: –surface: 1.4 x 1.6 cm 2 –Matrix of 256 x 256 –pixel size: 55 x 55 µm 2 For each pixel: –preamp/shaper –threshold discriminator –register for configuration –TimePix synchronization logic –14-bit counter 55  m Description of the TimePix chip

40. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200840 TimePix/Micromegas chambers NIKHEF –Next-1,2 & 3 –standard Micromegas –amorphous-Silicon protection against discharges –Ingrid: Integrated Micromegas using post-processing Saclay –Micro-TPC –standard Micromegas –amorphous-Silicon protection against discharges –6 cm height field cage

41. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200841 Cosmic-ray time Chamber Next-1 at NIKHEF TimePix chip + SiProt + Ingrid Gas mixture : He/Iso (80:20) Maximum drift: 10 mm Amplification gap: 50 μm Cosmic-ray track: –Length : ~ 18 mm –Width : ~ 200 μm Before SiProt chips used to die due to sparking but now … NIKHEF

42. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200842 Image of discharges are being recorded Round-shaped pattern of some 100 overflow pixels Perturbations in the concerned column pixels –Threshold? –Power? Chip keeps working !! Discharges are observed Provoke discharges by introducing small amount of Thorium in the Ar gas - Thorium decays to Radon 222 which emits 2 alphas of 6.3 & 6.8 MeV - Depose on average 2.5.105 & 2.7.105 e- in Ar/iC4H10 80/20 - at -420 V on the grid, likely to trigger discharges

43. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200843 TimePix/Micromegas Micro-TPC of Saclay Micro-TPC Timepix chip + SiProt 20 μm + Micromegas 90 Sr Ar/Iso (95:5) Time Mode z ~ 40 mm V mesh = -340 V

44. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200844 TimePix & GEMs Freiburg (+Bonn) Beam DESY II Trigger (scint.) & Si-telescope - Standard GEMs 100x100 mm2 with 140 μm of hole pitch - News GEMs 24x28 mm2 with 50μm of hole pitch puce TimePix : 14 mm Test beam at DESY in 2007 Several gas mixture and two GEM systems were tested Time TOT

45. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200845 ILC-TPC collaboration 41 institutes 120 physicists

46. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200846 Small prototypes

47. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200847 Large Prototype for ILC Endplate of 7 panels, ø = 80 cm Two readout technology : GEM & MICROMEGAS (bulk) anode, resistive anode, pixels 80 cm

48. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200848 EUDET/LCTPC setup at DESY Field cage (DESY) 1 T magnet (KEK)

49. David.Attie@cea.frINSTR08 – BINP, Novosibirsk – March 1 st, 200849 Conclusions Gaseous detectors have a long history behind them and they, especially TPCs, have a promising future The new MPGD technologies are now mature  unite in world-wide RD51 collaboration Physicists working on TPC R&D are now inside a huge collaboration over the world towards the future Linear Collider The ALICE TPC is getting ready for data taking at LHC T2K experiment will commission a large new generation TPC in 2009 TPCs will permit a large development of many applications, not only in particle tracking, as usually in high energy and heavy ions physics, but also in rare event detection