A Laser-based Time Calibration System for the MEG II Timing Counter

TL;DR

This paper introduces a laser-based calibration system for the MEG II timing counter, achieving 24 ps precision in timing alignment of scintillation counters, with potential applications in TOF-PET.

Contribution

A novel laser-based calibration system that directly measures time offsets of counters with high precision and stability for the MEG II detector.

Findings

Achieved 24 ps uncertainty in calibration.

Demonstrated system stability and consistency.

Successfully integrated into MEG II environment.

Abstract

We have developed a new laser-based time calibration system for the MEG II timing counter dedicated to timing measurement of positrons. The detector requires precise timing alignment between $\sim\,$500 scintillation counters. In this study, we present the calibration system which can directly measure the time offset of each counter relative to the laser-synchronized pulse. We thoroughly tested all the optical components and the uncertainty of this method is estimated to be 24 ps. In 2017, we installed the full system into the MEG II environment and performed a commissioning run. This method shows excellent stability and consistency with another method. The proposed system provides a precise timing alignment for SiPM-based timing detectors. It also has potential in areas such as TOF-PET.