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Recent developments for digital TPC readout Jan Timmermans - NIKHEF

Recent developments for digital TPC readout Jan Timmermans - NIKHEF. Micro Pattern Gas Detector: GridPix Integration of grid and readout: InGrid 3D readout: TimePix Discharge protection Future developments. Goals. Gas multiplication GEM or Micromegas foil(s)

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Recent developments for digital TPC readout Jan Timmermans - NIKHEF

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  1. Recent developments for digital TPC readoutJan Timmermans - NIKHEF • Micro Pattern Gas Detector: GridPix • Integration of grid and readout: InGrid • 3D readout: TimePix • Discharge protection • Future developments ECFA ILC Workshop

  2. Goals • Gas multiplication GEM or Micromegas foil(s) • Charge collection with granularity matching primary ionisation cluster spread (this needs sufficiently low diffusion gas) • Investigate measurement dE/dx using cluster counting • 2D “proof of principle” based on existing Medipix2 readout chip: achieved • Add 3rd coordinate: Medipix2  TimePix • Integrate grid with pixel chip: InGrid (new results) ECFA ILC Workshop

  3. Micro Patterned Gaseous Detectors GEM • High field created by Gas Gain Grids • Most popular: GEM & Micromegas Micromegas Use ‘naked’ CMOS pixel readout chip as anode

  4. Results pixel readout gas detectors NIKHEF-Saclay-CERN-Twente 55x55 μm2 pixels δ ray Ar/isobutane 95/5 Observation of min. ionising cosmic muons: high spatial resolution + individual cluster counting ! NIM A540 (2005) 295 (physics/0409048)

  5. (β source) (from Freiburg GEM+Medipix setup - Andreas Bamberger) Triple GEM Total gain ~60k ~ 50 μm resolution Difference between Micromegas and GEM setup understood (simulation Michael Hauschild/CERN) ECFA ILC Workshop

  6. Freiburg Bonn 4. Testbeam at DESY: 3-GEM+Medipix two tracks, d<1mm hard  electron Lots of data to be analyzed Still the same Medipix chip as 1.5 years ago Prepare for Testbeam with Timepix in same setup a.s.a.p. ECFA ILC Workshop

  7. ‘GEM’ ‘Micromegas’ InGrid Integrate GEM/Micromegas and pixel sensor By ‘wafer post processing’ 4” wafer 19 different fields of 15 mm Ø 2 bonding pads / fields

  8. NIKHEF/Twente: InGrid (Integrated Grid) Deposit SU-8 Deposit anode UV exposure Deposit metal Pattern metal Develop resist ECFA ILC Workshop

  9. Measuring the InGrid signals ( NIM A556 (2006) 490 ) (After 9 months of process tuning and unsuccessful trials) Pulseheight and gain: He + 20% iC4H10 • Gas gains 103 - 6∙104 ECFA ILC Workshop

  10. Energy resolution in Argon IsoC4H10 80/20 • Observation of two lines: • Kαat 5.9 keV • Kβ at 6.4 keV • Resolution σE/E = 6.5% • (FWHM = 15.3%) • Gain variations < 5% • Photo peak asymmetry seen • Very good energy resolution ECFA ILC Workshop

  11. Any field structure feasible ECFA ILC Workshop

  12. Gain Y. Giomataris/N.I.M. A419 (1998) 239-250 10000 1000 100 10 1 0.001 0.1 0.01 1 Gap (mm) Gain for different gap sizes Maximum predicted in gain vs gap curve d gap thickness V=400Volts V=350Volts V=300Volts p pressure A,B depend on gasmixture ECFA ILC Workshop

  13. Gain for different gap sizes • But now we can make measurements 105 500V 40um 450V 55um 400V 35um 75um 104 Gain 103 102 65 55 75 35 45 300 380 460 540 Gap thickness (μm) Grid voltage ECFA ILC Workshop

  14. Gain Gain y y x x 1.6 % RMS 2.6 % RMS Homogeneity • Gain measurements scanning the surface of the detector • Homogeneity given by grid quality ECFA ILC Workshop

  15. Measured gain for different hole size And measurements confirm simulations Gain 104 103 102 Vgrid 460 420 540 500 ECFA ILC Workshop

  16. 60 40 Resolution (FWHM %) 30 20 10 Gain 103 104 Energy resolution • Resolution depends on • Primary,attachment,T,P • Collection efficiency (field ratio) • Gain homogeneity & transverse diffusion ECFA ILC Workshop

  17. 35um 55um 50 75um 40 Resolution (FWHM %) 30 20 380 500 460 420 Resolution as function of gap Energy resolution • Why a parabolic behavior ? F. Jeanneau et al. NIM A 461 (2001) 84–87 Gain Vgrid ECFA ILC Workshop

  18. TimePix1(EUDET: Freiburg, Saclay, CERN, NIKHEF) • Distribute clock to full 256x256 pixel matrix • (50-100-160MHz) • Enable counting by first hit after ‘shutter’ opens, until ‘shutter’ closes (common stop); also time-over-threshold possible • Dynamic range 214 x 10 ns = 160 μs • (for the time being) no zero-suppress • to remain fullycompatible with Medipix2 • Shaping time ~200 ns • Keep same chip-size, pixel-size, readout • protocol • 1st full reticle submit done July 2006; • IT WORKS! Now preparing/doing tests in gas detectors.

  19. Sparking • Chip faces 80kV/cm with no protection (unlike the GEM setup; 1.5 yr using same chip) • Degradation of the field, or total destruction of grid but also CMOS chip 10μm ECFA ILC Workshop

  20. CMOS Chip protection against - discharges - sparks - HV breakdowns - too large signals Silicon Protection: SiProt Amorph Si (segmented) Empirical method: Try RPC technology ECFA ILC Workshop

  21. plasma A-Si - - - - • RPC principle: reduction of local E-field • Avalanche charge: electrostatic induction towards input pad • Specific resistance: - high enough to ‘block’ avalanche charge • - low enough to flow signal current • - layer thickness 4 μm, Rvol = 0.2 GΩ/cm Technology A-Si deposit possible in general; avoid wafers get too hot Univ. of Neuchatel/IMT/P. Jarron (CERN) uses this for integrated X-ray sensor/convertor on MediPix 2 Test: put Thorium in gas: Radon α-decays: - large (proportional) signals - Discharges: like short circuits ECFA ILC Workshop

  22. UNPROT PROT Slope less steep for protected anode NUE PROT Current reduced i ~ 2 A i ~4 A Enough to protect the chip? NUE PROT

  23. Gain Iron 55 source Look at the pulses from a pre amplifier (low grid voltage) Look at the current flowing through the power supply (high grid voltage) current pulses No sparks up to 570 V on the grid ! Burn the grid above 570…

  24. Alternative: TwinGrid ECFA ILC Workshop

  25. TripleGrid ECFA ILC Workshop

  26. Further Developments RELAXD project (Dutch/Belgian) NIKHEF,Panalytical,IMEC,Canberra: • Chip tiling: large(r) detector surfaces (2x2, 2x4 chips) • Through Si connectivity: avoiding bonding wires • Fast readout technology (~5 Gb/s) • Octal chip board: 56 mm x 110 mm 12-layer pcb ECFA ILC Workshop

  27. NIKHEF Harry van der Graaf Jan Timmermans Jan Visschers Maximilien Chefdeville Martin Fransen Vladimir Gromov Saclay CEA DAPNIA Paul Colas, David Attié Dan Burke,Yannis Giomataris Arnoud Giganon, Marc Riallot Univ. Twente/Mesa+ Jurriaan Schmitz Cora Salm Victor Blanco Carballo Sander Smits CERN Michael Campbell,Erik Heine Xavi Llopart Thanks to: Wim Gotink Joop Rovenkamp GridPix: the electronic bubble chamber ECFA ILC Workshop

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