Precision timing detectors

Abstract

Precision timing has played a critical role in high-energy physics experiments, particularly for particle identification and the suppression of pileup under the challenging conditions expected at future colliders like the High-Luminosity Large Hadron Collider (HL-LHC). Over the past decades, significant advancements in timing measurement technologies have been made to meet the demands of increasingly complex collider environments. After introducing the motivation for precision timing in collider experiments, the underlying physical principles of timing measurements and the most important factors influencing the time resolution of a detector, this review presents a survey of key detector technologies developed in recent years, including scintillators read out by silicon photo-multipliers (SiPMs), low-gain avalanche diodes (LGADs), multi-gap resistive plate chambers (MRPCs). The integration of precision timing into large-scale systems is discussed with examples from detectors at current collider experiments. Finally, we explore emerging technologies and future directions in the field, highlighting their potential impact on the next generation of high-energy physics experiments.

Figures (32)

• Figure 1: Particle velocity $\beta = v/c$ measured by the ALICE TOF as a function of momentum in Pb–Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV Carnesecchi:2018oss.
• Figure 2: Left: event display showing reconstructed tracks and vertices in a real collision event from a high pileup run in 2016 with 130 vertices Collaboration:2231915. Right: simulated (red-dots) and reconstructed vertices (blue) and tracks (black) in 200 pileup collisions using 4D tracking; vertices merged in 3D (yellow lines) are separated in 4D CERN-LHCC-2019-003.
• Figure 3: Left: pileup jet rejection as a function of hard-scatter jet efficiency with and without using timing information from the ATLAS High Granularity Timing Detector CERN-LHCC-2020-007. Right: distribution of $1/\beta$ for Heavy Stable Charged Particle signal events and background events from the SM Drell Yan + jets production, with and without using the precision track time information provided by the CMS MIP Timing Detector CERN-LHCC-2019-003.
• Figure 4: Schematic representation of the typical chain for timing measurements. Adapted from Rivetti.
• Figure 5: Effect of the noise on time measurements.