Sub-10 ps Minimum Ionizing Particle Detection With Geiger-Mode APDs Francesco Gramuglia 1† *, Emanuele Ripiccini 1† , Carlo Alberto Fenoglio 1 , Ming-Lo Wu 1 , Lorenzo Paolozzi 2,3 , Claudio Bruschini 1‡ and Edoardo Charbon 1‡ 1 Advanced Quantum Architecture Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), Neuchatel, Switzerland, 2 Departement de Physique Nucléaire et Corpusculaire, Université de Genève, Geneva, Switzerland, 3 European Organization for Nuclear Research, CERN, Meyrin, Switzerland Major advances in silicon pixel detectors, with outstanding timing performance, have recently attracted significant attention in the community. In this work we present and discuss the use of state-of-the-art Geiger-mode APDs, also known as single-photon avalanche diodes (SPADs), for the detection of minimum ionizing particles (MIPs) with best-in-class timing resolution. The SPADs were implemented in standard CMOS technology and integrated with on-chip quenching and recharge circuitry. Two devices in coincidence allowed to measure the time-of-flight of 180 GeV/c momentum pions with a coincidence time resolution of 22 ps FWHM (9.4 ps Gaussian sigma). Radiation hardness measurements, also presented here, highlight the suitability of this family of devices for a wide range of high energy physics (HEP) applications. Keywords: avalanche photodiode, beamline, particles, sensor, time-of-flight 1 INTRODUCTION 1.1 High Timing Resolution With Silicon Pixel Detectors Silicon pixel detectors have been developed in high-energy physics applications to provide precise position measurements thanks to their compactness and high spatial granularity. Recent developments have been focused on sub-100 ps timing measurements of optical photons and direct detection of charged particles. When a particle passes through the detector, electron-hole pairs are generated. When these charges move in the depletion region, an induced current pulse is registered on one electrode. According to the Schockley-Ramo theorem [1, 2], this current is proportional to the free charge Q, to the speed of the charge carriers v, and to the weighting field, which can be expressed, to a first approximation, as 1 d , where d is the thickness of the depletion region. Hence, we can calculate the induced current as: i  kQv 1 d , (1) where k is a proportionality factor. The signal ends when all charges have been collected. Moreover, in case of a minimum ionizing particle (MIP) crossing a thin device, the charge Q is proportional to d. We thus have: i  kNdv 1 d  kNv, (2) Edited by: Mariana Frank, Concordia University, Canada Reviewed by: Lucio Pancheri, University of Trento, Italy Gabriele Giacomini, Brookhaven National Laboratory (DOE), United States *Correspondence: Francesco Gramuglia Francesco.gramuglia@epfl.ch † These authors share the first authorship ‡ These authors share the last authorship Specialty section: This article was submitted to High-Energy and Astroparticle Physics, a section of the journal Frontiers in Physics Received: 05 January 2022 Accepted: 08 April 2022 Published: 11 May 2022 Citation: Gramuglia F, Ripiccini E, Fenoglio CA, Wu M-L Paolozzi L, Bruschini C and Charbon E (2022) Sub-10 ps Minimum Ionizing Particle Detection With Geiger- Mode APDs. Front. Phys. 10:849237. doi: 10.3389/fphy.2022.849237 Frontiers in Physics | www.frontiersin.org May 2022 | Volume 10 | Article 849237 1 REVIEW published: 11 May 2022 doi: 10.3389/fphy.2022.849237