Timepix in EUDet – CERN contribution Michael Campbell PH Department CERN Geneva, Switzerland Spokesman, Medipix2 Collaboration

4 January 2006Michael Campbell The Medipix2 Consortium  Institut de Fisca d'Altes Energies, Barcelona, Spain  University of Cagliari and INFN Section thereof, Italy  CEA, Paris, France  CERN, Geneva, Switzerland,  Universitat Freiburg, Freiburg, Germany,  University of Glasgow, Scotland  Universita' di Napoli and INFN Section thereof, Italy  NIKHEF, Amsterdam, The Netherlands  University of Pisa and INFN Section thereof, Italy  University of Auvergne, Clermont Ferrand, France,  Laboratory of Molecular Biology, Cambridge England  Mitthogskolan, Sundsvall, Sweden,  Czech Technical University, Prague, Czech Republic  ESRF, Grenoble, France  Academy of Sciences of the Czech Republic, Prague  Universität Erlangen-Nurnberg, Erlangen, Germany  University of California, Berkeley, USA

4 January 2006Michael Campbell Hybrid Pixel Detector Detector and electronics readout are optimized separately

4 January 2006Michael Campbell Hybrid Pixel Detector - Cross Section

4 January 2006Michael Campbell Charge sensitive preamplifier with individual leakage current compensation 2 discriminators with globally adjustable threshold 3-bit local fine tuning of the threshold per discriminator 1 test and1 mask bit External shutter activates the counter 13-bit pseudo-random counter 1 Overflow bit Medipix2 Cell Schematic

4 January 2006Michael Campbell Medipix2 Cell Layout

4 January 2006Michael Campbell Medipix2 Chip Architecture 256 x 256 pixels 10ms readout time

4 January 2006Michael Campbell Medipix2 Chip Architecture (II)

4 January 2006Michael Campbell Electrical measurements Electron Collection Hole Collection Gain12.5 mV/ke13.25 mV/ke Non linearity<3% to 100ke - <3% to 80ke - Peaking time<150ns Return to baseline <1  s for Qin <50 ke - Electronic Noise  nL~ 110 e-  nH~ 110 e- Threshold dispersion  nTHL~ 360 e- (~ 90 e- tuned) Analog power dissipation ~8  W/channel for 2.2V supply

4 January 2006Michael Campbell Medipix2 bump bonded to a 300  m thick Si sensor

4 January 2006Michael Campbell Bumps of readout side

4 January 2006Michael Campbell Bumps of readout side – close up

4 January 2006Michael Campbell Under bump metallization on sensor side

4 January 2006Michael Campbell Medipix2 Readout - Muros2 65 units produced plug and play Suitable for single chip and for up to N-chip daisy chain Will run up to 200 MHz: N x 5 ms readout J. Visschers et al. Nikhef

4 January 2006Michael Campbell Medipix2 Readout - USB Courtesy: Jan Jakubek, Praha S. Pospisil et al., CTU Prague

4 January 2006Michael Campbell Image of a dried anchovy

4 January 2006Michael Campbell Image of a fly

4 January 2006Michael Campbell Image of a leaf ( 55 Fe)

4 January 2006Michael Campbell Ticking Swatch 5 frame/sec. Limited by DAQ software

4 January 2006Michael Campbell MediPix2 pixel sensor Brass spacer block Printed circuit board Aluminum base plate Micromegas Cathode (drift) plane 55 Fe Baseplate Drift space: 15 mm Very strong E-field above (CMOS) MediPix! Sinlge electron detection using Medipix2 H. Van der Graaf and coworkers Nikhef

4 January 2006Michael Campbell MediPix modified by MESA+, Univ. of Twente, The Netherlands Pixel Pitch: 55 x 55 μm 2 Bump Bond pad: 25 μm octagonal 75 % surface: passivation SiN New Pixel Pad: 45 x 45 μm 2 Insulating surface was 75 % Reduced to 20 % Chip post processing

4 January 2006Michael Campbell Micromegas-Medipix2 setup

4 January 2006Michael Campbell Chamber Mechanics

4 January 2006Michael Campbell He/Isobutane 80/20 Non Modified MediPix Americium Source Radioactive source observation

4 January 2006Michael Campbell He/Isobutane 80/20 Modified MediPix Cosmic with associated delta ray

4 January 2006Michael Campbell Timepix Development  Proposed in 2003 but funding difficult  Timepix included in EUDet proposal  Brainstorming meetings at CERN  Outcome Keep Timepix as similar as possible to Medipix2 in order to benefit from large prior effort in R/O hardware and software Avoid major changes in pixel and/or readout logic – risk of chip failure due to poor mixed mode modelling Eliminate 2nd threshold Add possibility of programming pixel by pixel arrival time or TOT information  2 possible timestamp methods under study Local oscillator per pixel Clock sent to all pixels

4 January 2006Michael Campbell TOT in one pixel TOT width as a function of threshold for a constant input charge

4 January 2006Michael Campbell Conclusions  TimePix is heavily based on Medipix2 effort  CERN, Nikhef (J. Visschers), Napoli (P. Russo) and recently Prague (S. Pospisil) have been main contributors to Medipix2  Changes to functionality for TimePix should be minimized to avoid chip design failures  Work on simulating the new possible architectures is already underway (X. Llopart)