1. richard.plackett@cern.ch 1 The Medipix3 and Timepix2 Chips Applications and Future Developments Richard Plackett, University of Glasgow VERTEX2010, Loch Lomond, 8 th June 2010 On behalf of the Medipix Collaboration and Xavier Llopart in particular

2. richard.plackett@cern.ch 2 Outline Current Detectors – Medipix2 and Timepix Chip Descriptions Principles of Operation Current Developments - Medipix3 Chip Description Development Issues Future Projects – Timepix2 Proposed Chip Designs and Ideas Applications Dosimitry, Education, Microscopy, Tracking, Photon Detection, Medical Imaging

3. richard.plackett@cern.ch 3 Two Collaborations Medipix2 INFN Cagliari CEA-LIST Saclay CERN Geneva University of Erlangen University of Freiburg ESRF Grenoble University of Glasgow University of Houston IFAE Barcelona Mid Sweden University MRC-LMB Cambridge INFN Napoli NIKHEF Amsterdam INFN Pisa FZU CAS Prague IEAP CTU Prague SSL Berkeley Medipix3 ALMOF Amsterdam University of Bogota University of Canterbury NZ CEA-LIST Saclay CERN Geneva DESY Hamburg Diamond Light Source University of Erlangen ESRF Grenoble University of Freiburg University of Glasgow ITER University of Karlsruhe Leiden University Mid Sweden University NIKHEF Amsterdam IEAP CTU Prague SSL Berkeley VTT Microsystems 21 collaborating institutes

4. richard.plackett@cern.ch 4 The Medipix Chips A philosophy of functionality built into the pixel matrix allows complex behavior with a minimal inactive region 55um square pixel matrix 256 by 256 Configurable ‘shutter’ allows many different applications Silicon, 3D, CdTe, GaAs, Amorphous Silicon, Gas Amplification, Microchannel Plates etc…

5. richard.plackett@cern.ch 5 Development Path Medipix1 1um SCAMOS 64 by 64 pixels Photon Counting Demonstrator (1997) 250nm IBM CMOS, 256 by 256 55um pixels Full photon counting (2002) 130nm IBM CMOS Photon Counting, Spectroscopic, Charge Summing, Continuous Readout (2009) Fast front end, Simultaneous ToT and ToA (2011) Analogue (ToT) and Time Stamping (ToA) (2006) 130nm/90nm/65nm Future LHCb readout – Data driven 40MHz ToT 12Gb/s per chip (2013) Medipix2 Timepix Medipix3 Timepix2 VELOpix CLICpix 130nm/90nm/65nm Future Hybrid Pixel Time tagging layer for the LCD project (20??)

6. richard.plackett@cern.ch 6 Medipix2 and Timpix

7. richard.plackett@cern.ch 7 Medipix2 (2002) – Photon Counting sensor Analogue amplification Digital processing Chip read-out 11 1 2 3 2 Each hit in the sensor is converted into a count in the 13 bit counter Noise and below threshold events are not counted at all 1000 electron noise floor The shutter closes and the data are shifted out

8. richard.plackett@cern.ch 8 Medipix2 Applications The most commercialized of the current chips and being sold by PANalytical (NL) in X-Ray Diffractometers Also active applications in – Material Analysis – Medical Imaging – Synchrotron Light Source Instrumentation – Micro CT material analysis – Proton Beam Monitoring (at the SPS) – Electron microscopy – Mass spectrometry – Neutron Imaging – Charged Particle Dosimitry

9. richard.plackett@cern.ch 9 Timepix (2006) sensor Analogue amplification Digital processing Chip read-out Timepix design requestedand funded by EUDET collaboration Conventional Medipix2 counting mode remains. Addition of a clock up to 100MHz allows two new modes. Time over Threshold Time of Arrival Pixels can be individually programmed into one of these three modes Time over Threshold Threshold Time Over Threshold counts to the falling edge of the pulse Threshold Time of Arrival Time of Arrival counts to the end of the Shutter

10. richard.plackett@cern.ch 10 Or As Results… Time of Arrival Strontium Source Time over Threshold Ion Beams at HIMAC Charge deposition studies with various Isotopes Space Dosimetry Courtesy L. Pinsky, Univ. Houston

11. richard.plackett@cern.ch 11 Timepix Applications New Tracking Technologies – LHCb Upgrade – CLIC detectors – Solid state Detector Development TPC instrumentation – EUDET Emission Channeling Crystal Lattice Experiments – ISOLDE Image Intensifiers / Optical Photon Detectors – Adaptive Optics – Bioimaging – LHCb RICH ToF Mass Spectrometry – Proteomic Imaging at AMOLF and Oxford Imaging Mass Spec – Functional Cellular Biology at Kiev Photo Electron Emission Microscopy and Low Energy Electron Micrsocopy Neutron Monitoring at CNGS Space Dosimintry Education - CERN@School As yet no one has sold any Timepix products, but lots of Interesting science is being done with them

12. richard.plackett@cern.ch 12 Applications A few examples as shown at various Medipix Collaboration Meetings

13. richard.plackett@cern.ch 13 LHCb Testbeam 6 pixel telescope planes angled in 2 dimensions to optimise resolution Device Under Test moved and rotated via remote controlled stepper motor Fine pitch strip detector with fast electronics readout

14. richard.plackett@cern.ch 14 ATLAS Neutron Dosimitry LiF (50 µm) used for thermal neutrons detection Uncovered accepts all particles low sensibility to neutrons PE (1.3 mm) used for fast neutrons detection PE + Al used for fast neutrons detection removing low energy electron photons contributions Al (50 and 100 µm) used to stop low energy electrons and photons J. Jakubek, S. Pospisil, M. Suk, D. Turecek and Z. Vykydal and the Group at Prague CTU

15. richard.plackett@cern.ch 15 CERN@ School / LUCID Langton Ultimate Cosmic-ray Intensity Detector – A space based directional cosmic ray experiment – Operated by Simon Langton Grammar School (Kent) – Joint project with CERN and SSTL – Launch 2011…. CERN@School – Timepix chips in classrooms as ground based wide area cosmic ray detectors – Also excellent teaching aids for radioactivity – Possibility of loaning systems to schools – Feasible to construct remotely operated systems to log into As a Teaching Aid – Americium Source No filter, alpha particles and photonsTape filter, only photons Half covered shows the difference

16. richard.plackett@cern.ch 16 Low Energy Electron Microscopy Images of Graphene Flakes presented to the Medipix2 collaboration by I. Sikharulidze, Leiden ‘Medipix2 applied to low energy electron microscopy’, Ultramicroscopy 110 (2009) 33 - 35 MCP + CCD imagesMedipix2 Images

17. richard.plackett@cern.ch 17 Photon Detectors Glasgow HPD Berkeley MCP phototube Medipix2 Funded Quad Phototube Four Timepix in a square phototube Collaboration between: Berkeley CERN Erlangen Glasgow Nikhef Many applications With VELOpix even LHCb RICH upgrade possbilities

18. richard.plackett@cern.ch 18 UA9 - Crystal Beam Channeling for sLHC Data and analysis by L. Tlustos on behalf of the UA9 collaboration

19. richard.plackett@cern.ch 19 Dental Imaging Readout system, data analysis and teeth J. Jakubek, Prague CTU

20. richard.plackett@cern.ch 20 Medipix3

21. richard.plackett@cern.ch 21 Medipix3 (2009) 17.3 mm 14.1 mm Increased pixel to pixel communication Several advantages over Medipix2 Charge summing mode – prevents spectral distortion due to charge sharing Spectroscopic mode – four pixels to sharing thresholds and counters Two counters per pixel – allowing continuous shutter based readout Increased Radiation Tolerance – From 130nm CMOS process

22. richard.plackett@cern.ch 22 Medipix3 Modes Pixel Operation ModesPixel size# Thresholds Single Pixel Fine Pitch Mode → 55 µm x 55 µm2 Charge Summing Colour Mode Spectroscopic Mode → 110 µm x 110 µm8 Colour Mode with charge Summing Pixel Gain ModesLinearity# Thresholds High Gain Mode~10 ke - 2 Low Gain Mode ~20 ke - Pixel Counter ModesDynamic range# Counters 1-bit 12 4-bit 152 12-bit 40952 24-bit 167772151 Pixel Readout Modes# Active CountersDead Time Sequential Count-Read (SCR) 2Yes Continuous Count-Read (CCR)1No

23. richard.plackett@cern.ch 23 Medipix3 Charge Summing Mode sensor Analogue amplification e- h+ Digital processing Chip read-out 10001110101 A hit in the sensor deposits charge The charge passes to the analogue amplifiers The Medipix 3 charge summing circuit operates The counter is iterated and read out with the shutter

24. richard.plackett@cern.ch 24 Medipix3 Charge Summing Mode 10001110101 A hit in the sensor deposits charge across four pixels The analogue comparators assign the charge to the pixel with the most hits This prevents ‘lost’ charge by partial hits not passing threshold The threshold is applied to the summed charge and read out when the shutter closes Medipix3 can be configured to sum charge across four pixel clusters to prevent hits being lost due to charge sharing

25. richard.plackett@cern.ch 25 Charge Summing Charge sharing events produce a low energy smearing of the landau Initial Measurements of Medipix3 indicate the charge summing circuitry works as expected Single pixel mode Charge Summing Mode Measurement by L.Tlustos and R. Ballabriga CERN

26. richard.plackett@cern.ch 26 Spectroscopic (Colour) Mode By connecting 4 pixels into a larger super pixel, eight threshold levels are available to us in the digital part of the pixel… Counter 1 Counter 2 Counter 3 Counter 4 Counter 5 Counter 6 Counter 7 Counter 8 Amplifier response Each threshold is adjustable, allowing a wide range of settings. This gives us enough flexibility to capture reasonable spectra in many different applications

27. richard.plackett@cern.ch 27 Medipix3 Radiation Hardness 130nm CMOS was expected to be very tolerant to integrated dose from test chip measurements So far Medipix3 has been tested with an X- Ray flux up to 500MRad and has remained operational 460MRad 400MRad Noise Floor Signal

28. richard.plackett@cern.ch 28 Medipix3 Matching Problems One of the major debugging efforts in Medipix3 is a larger than expected pixel to pixel threshold variation Especially obvious in charge summing mode Design team in close contact with IBM to solve matching Issues

29. richard.plackett@cern.ch 29 Can Still take Beautiful Images Image of a leaf with Fe 55 source 930 e - minimum threshold Courtesy of R. Ballabriga - CERN

30. richard.plackett@cern.ch 30 Medipix3 Applications Multi-Energy CT – Spectroscopic Imaging mode SLS instrumentation – Radiation tolerance and continuous readout High Z Sensor Development (see David’s talk) – Charge summing to produce correct landaus Beam Monitoring – Radiation Tolerance Irradiated Sensor Development – Radiation Tolerance

31. richard.plackett@cern.ch 31 Multi Spectral CT With thanks to University of Canterbury NZ and the MARS team

32. richard.plackett@cern.ch 32 Timepix2

33. richard.plackett@cern.ch 33 Timepix2 Proposals (2013?) Timepix2 Design is still in flux Simultaneous ToT and ToA Sub 25ns rise time Fast fine timing ~1ns Many ideas for the remaining details Possible data driven scheme akin to VELOpix allowing high readout rates and continuous sensitivity Small pixels with highly configurable interconnects in an FPGA-like design Shutter? Trigger? Frame based? Sparse Readout?

34. richard.plackett@cern.ch 34 Data Driven Timepix2 The ‘ideal’ detector will read out all hits… An attempt to get close to this is the ‘Data Driven’ design Will push all events off the chip up to a limiting event rate Good for low rate and sparse applications Problematic for SLS physics or high rate imaging Cannot use the shutter to ‘squeeze down’ data rates Closer to ideal but not useable for all applications Requires significant on matrix logic and readout infrastructure to achieve high data rates

35. richard.plackett@cern.ch 35 A Data Driven Timepix2 (VELOpix) Limited to sparse readout Super pixel architecture to compress clustered data on matrix Very high maximum data rate Digital readout Analog DACs A multi pixel cluster can be read out much more efficiently in a super pixel architecture However this is quite a strongly optimised design, possibly not ideal for all applications 220um

36. richard.plackett@cern.ch 36 An FPGA-Like Timepix2 Small (27.5um) pixels, each with a clock, threshold and counter could be combined in a reconfigurable way Amplifier 55um Discriminator ToT / ToA / Count Counter / Memory Amplifier Discriminator ToT / ToA / Count Counter / Memory Amplifier Discriminator ToT / ToA / Count Counter / Memory Amplifier Discriminator ToT / ToA / Count Counter / Memory A pixel that can measure ToT and ToA simultaneously, with deep counters A large area Timing pixel with a very deep counter High resolution ToT pixels for tracking Not Necessarily Technically Feasible Concept by J. Jakubek Prague CTU

37. richard.plackett@cern.ch 37 Timepix2 Possible Applications Particle Tracking – LHCb, LCD interest Molecular ToF spectrometry TPC readouts Neutron Dosimitry Double Beta Decay & Neutrino Capture Experiments …

38. richard.plackett@cern.ch 38 To Conclude Medipix2 and Timepix have been successful so far and built a large ecosystem of applications. Medipix3 shows promise, initial verification complete and working with IBM to solve remaining problems. Timpix2 is being designed/specified at the moment with a robust discussion about the required performance and how to achieve it.

39. richard.plackett@cern.ch 39 Backup Slides

40. richard.plackett@cern.ch 40 Chip Noise Details Medipix2 noise floor 1000 electrons Timepix 650 electrons Medipix3 75 electrons

41. richard.plackett@cern.ch 41 Timepix (2006) An evolution of the Medipix2 chip Similar architecture replacing a discriminator level with 100MHz clock signal and three operating modes Each pixel is individually programmable into one mode – Time of Arrival – Time Tagging – Time over Threshold – Analogue Hit Information – Medipix - Hit Counting

42. richard.plackett@cern.ch 42 Timepix Modes of Operation Threshold ToT and ToA modes make use of the timepix clock to record the time between passing threshold and another event Time Over Threshold counts to the falling edge of the pulse Time of Arrival counts to the end of the Shutter

43. richard.plackett@cern.ch 43 Medipix2 – Details 256 by 256, 55um square pixels Pixel columns read out as shift registers when shutter closes ~1.5ms minimum full matrix readout Noise floor ~1000e- 3 bit threshold trim 16.1 mm 14.1 mm A Medipix2 wafer undergoing QA wafer probing

44. richard.plackett@cern.ch 44