Séminaires du DPhP: Time-of-flight: towards ultimate resolution with modern SiPMs and scintillators

par Stefan Gundacker (CERN)

lundi 30 juin 2025, 11:00 → 12:30 Europe/Paris

CEA Paris-Saclay

The ability to measure the arrival time of particles is important in many applications, including high-energy physics, industry and medicine. For example, single optical photon detection and time tagging are employed in light detection and ranging (LiDAR) systems for the automotive industry, as well as in optical tomography and fluorescence lifetime measurements in the medical area. In these fields, silicon photomultipliers (SiPMs) have demonstrated excellent single-photon-counting and time-resolution capabilities. Coupling inorganic scintillators to SiPMs extends this concept to time-tagging gamma and X-ray photons in time-of-flight (TOF) positron emission tomography (PET) and computed tomography (CT), as well as minimum ionizing particles in high-energy physics experiments. Continuous SiPM development (e.g. high photon detection efficiency, UV detection, low dark count rate and crosstalk, etc.) has made it possible to explore new and well-established scintillator materials and, for the first time, use various fast emission mechanisms efficiently.

The first part of this presentation will provide a concise introduction to SiPMs, covering their basic principles and operation. The focus will be on the single-photon time resolution (SPTR) of modern devices, and on how advances in readout electronics have enabled the determination of intrinsic limits. The second part will provide an overview of the time resolution of various inorganic scintillators when read out with SiPMs. In addition to cross-luminescence, an ultra-fast emission mechanism, the presentation will discuss Cherenkov detection with bismuth germanate (BGO). BGO has recently gained interest in positron emission tomography due to its cost-effectiveness and high stopping power, making it particularly interesting for total body PET applications. The presentation will conclude with a summary and an outlook on future research directions.

zoom connection: https://cern.zoom.us/j/68399739111?pwd=SGErcHBQYmVLWFZTVE9jdm5xSmdEdz09