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Overview Medipix

Overview Medipix. Medipix ROC’s. Medipix2 Single pixel pulse processing event counting Timepix Single pixel pulse processing Counting Time of Arrival Time over Treshold Medipix3 Distributed pulse processing “Spectroscopic“ event counting. MEDIPIX2 Collaboration.

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Overview Medipix

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  1. Overview Medipix

  2. Medipix ROC’s • Medipix2 • Single pixel pulse processing • event counting • Timepix • Single pixel pulse processing • Counting • Time of Arrival • Time over Treshold • Medipix3 • Distributed pulse processing • “Spectroscopic“ event counting

  3. MEDIPIX2 Collaboration • U INFN Cagliari • CEA-LIST Saclay • - CERN Genève • U d'Auvergne Clermont • - U Erlangen • - ESRF Grenoble • - U Freiburg • - U Glasgow • - IFAE Barcelona • - Mitthoegskolan • - MRC-LMB Cambridge • - U INFN Napoli • - NIKHEF Amsterdam • - U INFN Pisa • - FZU CAS Prague • IEAP CTU in Prague • SSL Berkeley http://medipix.web.cern.ch/MEDIPIX/

  4. MEDIPIX3 Collaboration • University of Canterbury, Christchurch, New Zealand • DRT/LIST/DeTeCS/SSTM, CEA, Paris, France • CERN, Geneva, Switzerland, • DESY-Hamburg, Germany • The Diamond Light Source, Diamond House, Didcot, UK • FreiburgerMaterialforschungszentrum, Albert-Ludwigs-Universität  Freiburg, Germany, • University of Glasgow, Scotland, UK • Institute for Synchrotron Radiation, ISS, Forschungszentrum Karlsruhe, Germany • Biophysical Structural Chemistry, Leiden Univ., The Netherlands • NIKHEF, Amsterdam, The Netherlands • Mid Sweden University, Sundsvall, Sweden • IEAP, Czech Technical University, Prague, Czech Republic • ESRF, Grenoble, France • Universität Erlangen-Nurnberg, Erlangen, Germany • Space Sciences Laboratory, University of California, Berkeley, USA • Microsystems, VTT Information Technology, Espoo, Finland

  5. Current Applications • General purpose imaging detector • Dental radiography • Mammography • Angiography • Dynamic autoradiography • Tomosynthesis • Synchrotron applications • Electron-microscopy • Gamma camera • X-ray diffraction • Neutron detection • Dynamic defectoscopy • Adaptative optics • Radiation monitor • Mass spectrometry • Sparse data (mostly Timepix) • Tracking • TPC • Velocity map imaging • > 150 publications in the last 5 years (http://www.cern.ch/Medipix) • Collaboration spokesman Michael Campbell (michael.campbell@cern.ch)

  6. Hybrid-Pixel Detektor

  7. Medipix2 bump bonding SENSOR pitch 55 µm CMOS RO pitch 55 µm

  8. Medipix ROC’s overview References: http://medipix.web.cern.ch/MEDIPIX Thesis X. Llopart: Design and characterization of 64K pixels chips working in single photon processing mode The Medipix3 Prototype, a Pixel Readout Chip Working in Single Photon Counting Mode With Improved Spectrometric Performance

  9. Medipix2 Pixel • Positive und negative input signals→ alternative detector materials (GaAs, CdTe …) • Charge sensitive preamplifier with leakage current compensation per pixel • 2 Discriminators with globally adjustable threshold • 3-bit threshold adjustment per pixel • Counter aktiviation via external shutter signal • 1 test-bit and 1 mask-bit per pixel • 13-bit Pseudo-random counter Previous Pixel Shutter Mux Maskbit Polarity ClockOut 3 bits threshold Vth Low Disc1 Mux Double Disc logic Preamp Input 13 bits Shift Register Disc2 Vth High Ctest 3 bits threshold Conf Testbit 8 bits configuration Maskbit Test Input Next Pixel Analog Digital

  10. MedipixSignal Processing Threshold level N+ P+ • Threshold level >> electronic noise • No false counting. Digital integration (counting) • No dark current. Unlimited dynamic range and exposure time. Detected count obeys poissonian distribution + Si Bias Voltage Amplifier Counter: Compa rator Pixellated front-side electrode Common back-side electrode Particle count 001 000 Pixel electronics

  11. Energy window Medipix2 16.1-19.6 keV 21.6-25.1 keV 29-33.5 keV 36.9-40.4 keV 43.1-46.6 W-Röhre 50 kV 2.5 mm Al DE=3.5 keV

  12. (Random) Application examples • Small animal CT • Spectroscopic dataset for material reconstruction, • Mars bio imaging., NZ • Mass spectrometry, Kiev, UA • MPX in focal plane of spectrometer, ~10keV ions • PANalytical • Industrial Partner • Technology Transfer

  13. (Random) Application examples Small animal CT Univ. Erlangen Neutron imaging Left: Boron doped Micro channel plate, Univ. California Right: LiF converter, IEAP Prague Phase contrast imaging Right: Propagation phase contrast, IEAP Prague Right: Grating interferometer, PSI

  14. Timepix • Readout chip fully compatible with Medipix2 electronics/software • 3 operational modes • Counting ( = Medipix2) • Time over threshold mode (~ energy deposited) • Arrival time mode • Mode can be set in each pixel independently, allowing for concurrent energy and arrival time measurements

  15. TimePix TOT (ADC) Mode withSilicon Detector Layer Threshold level N+ P+ • Threshold level >> electronic noise • No false counting. Digital integration (counting) • No dark current. Unlimited dynamic range and exposure time. Detected count obeys poissonian distribution + Si Bias Voltage Amplifier Counter: Compa rator Pixellated front-side electrode Common back-side electrode Particle count Energy 000 007 003 001 Pixel electronics

  16. 50um Micromegas Micromegas • A novel approach for the readout of a TPC at the future linear collider is to use a CMOS pixel detector combined with some kind of gas gain grid • Using a bare photon counting chip Medipix2 coupled to GEMs (A.Bamberger, M.Titov, Freiburg) or Micromegas (J.Timmermans, NIKHEF) demonstrated the feasibility of such approach

  17. GEM GEM • A novel approach for the readout of a TPC at the future linear collider is to use a CMOS pixel detector combined with some kind of gas gain grid • Using a bare photon counting chip Medipix2 coupled to GEMs (A.Bamberger, M.Titov, Freiburg) or Micromegas (J.Timmermans, NIKHEF) demonstrated the feasibility of such approach

  18. Timepix with 3-GEM detector • DESY testbeam in November 2006 (A.Bamberger, M.Titov)

  19. Bunch period 176ns (~100ps) Bunch period 176ns

  20. Stopping Heavy Charged ParticlesTotal Energy Resolution Am241+ Pu239 combined source 5.2 MeV and 5.5 MeVa “Heavy” calibration extrapolation Cluster volume (energy) spectrum (measured in air) 0.67% Gaussian fit sigma = 37 keV Max. spatial resolution ~0.5 μm J. Jakubek et al. / Nuclear Instruments and Methods in Physics Research A 591 (2008) 155–158

  21. 11B HIMAC @ 0 @ 60 @ ~90 Charge deposition studies with various Isotopes → Space Dosimetry

  22. → Quantum Dosimetry • Different particles have different event signatures use cluster finding algorithms and decoding of event morphology • New application: online dosimetry • 15 MPX2 installed in ATLAS 241Am alpha source 55Fe X-ray source 90Sr beta source

  23. Description of the detector Medipix2 ASIC with 300µm Si sensor + USB interface Neutron conversion structures: LiF+50µm Al foil area 100µm Al foil area PE area PE+50µm Al foil area Uncovered area

  24. Neutron efficiencycalibration X-ray image of conversion layers Thermal neutrons – 500s, 25meV PE / PE+Al cluster count ratio: 252Cf: 10.70 ± 0.04 AmBe: 5.18 ± 0.03 VDG: 2.51 ± 0.03 252Cf – 2000s, 2MeV (mean) AmBe – 2000s, 4MeV (mean) Van de Graaff – 1000s, 14MeV LiF PE PE + Al Al Uncovered Fixed HIGH threshold (~200keV) Calibrated efficiency: Thermal: 1.41E-2 ± 7.11E-4 cm-2s-1 252Cf: 1.19E-3 ± 1.89E-5 cm-2s-1 AmBe: 2.86E-3 ± 5.46E-5 cm-2s-1 VDG: 7.23E-3 ± 5.81E-4 cm-2s-1

  25. Charge Transport in Planar Detectors Mono-energetic Photons 20 keV 20 keV Photons 300 m Si Sensor 55 m Pixel Pitch 120 V sensor bias • Mono-energetic Photon spectrum continuous spectrum with  constant background and strong contribution of low pulse heights • Even when using energy window spectroscopic information degraded

  26. Spectral X-ray source Simulation of the effective pulse height distribution as seen by pixel electrodes Photon Spectrum Detected spectrum Corrected Pixel Spectrum Summation of signals from 3x3 pixel cluster

  27. Charge Summing Implementation • Off chip: Timepix like architecture • Digitization of energy deposited in pixel →TOT • Sparse data, no overlaps → limited photon flux • Fast readout necessary • On chip: Medipix3 • Communicating pixels • Dead time/pileup limit given by shaping time • Summing of 4 adjacent pixels • 4 (8) Energy bins

  28. Medipix3 - Charge Summing Architecture The winner takes all • Charge is summed in every 4 pixel cluster on an event-by-event basis • The incoming quantum is assigned as a single hit 55 m

  29. MPX3 first results • Just back from foundry • Extensive testing going on • + HW integration • + Software • ….. • Works, only few issues found

  30. Outlook, in general • In the pipeline • Next generation of RO systems • RelaxD (Nikhef, Panalytical): 4 chip • Mars (Canterbury): 6 chip • Ruin (IEAP, Prague): single chip • PRIAM for MPX3, ESRF • New sensors • 150, 300 and 1mm thick Si • GaAs, CdTe • Amorphous Si, Amorphous CdTe (-> rad hard) • Next ? • “Timepix2”, in discussion for LHCbvelo upgrade: square pix, fast ToT/ToA tracking framerate ≥100 Hz framerate ≥1 KHz

  31. Outlook, in particular • 2nd Medipix in Roman Pot 1 • 3rd (4th?) Medipix in Roman Pot 2 • In coincidence • Tracking algorithm • RO upgrade ≥100 Hz framerate • Alternative sensors • Edgeless sensors (50 m insensitive area) • Prototypes so far … • Amorphous Si, amorphous CdTe • 1 mm Si → solid state TPC

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