Detection of Photons and Charged Particles using Silicon Radiation Sensor with 3D Electrodes and Timepix3 Hybrid Detector

  • Tianqi Gao

Student thesis: Phd


This thesis presents the characterisation of a 3D Timepix3 hybrid detector, and its comparison with a corresponding planar one using radioactive sources, pion test beams, and mixed heavy ion test beams at the CERN, SPS. The energy spectra of all measurements were similar between 3D and planar, and the 3D Timepix3 assembly showed lower charge sharing and better charge collection efficiency. The cluster size distributions for 3D were concentrated in a single cluster size while for planar were spread to a wide spectrum, with the start of the spectrum usually being the same as the mode of 3D. The planar detector's per-pixel maximum energy was 600 keV, where for 3D was 850 keV, this could be due to higher charge collection efficiency. It was also found that, due to the complex electric and weighting field distributions of the partial-3D geometry, there are volumes in the sensor where charge drift time is unexpectedly long. When partial 3D sensors (sensors with electrodes that do not fully extend through the bulk) is used in conjunction with a fast timing readout like Timepix3, this effect could be exploited to improve the spatial resolution for the 3D sensor from p/sqrt(12) to 0.25p/sqrt(12); and add a depth spatial resolution of 7.5 um, where p is pixel pitch. This improved spatial resolution could open up ways to possible 3D track reconstruction using 2 cm2 3D sensors.
Date of Award1 Aug 2021
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorCinzia Da Via (Supervisor) & Yvonne Peters (Supervisor)


  • semiconductor
  • test beam analysis
  • hybrid detector
  • Timepix3 detector
  • 3D silicon sensor
  • particle detection
  • photon detection
  • radiation damage
  • radiation detector

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