Measurement of time resolution of the Mu2e LYSO calorimeter prototype

TL;DR

This paper reports on the time resolution measurements of a LYSO calorimeter prototype for Mu2e, demonstrating a resolution of approximately 162 ps at 100 MeV energy, using beam tests at Frascati.

Contribution

First measurement of the time resolution of a LYSO calorimeter prototype for Mu2e over a range of energies using beam tests.

Findings

Time resolution of 162 ps at 100 MeV

Energy dependence follows a/√E ⊕ b parametrization

Stochastic term a=51 ps, constant term b=10 ps

Abstract

In this paper we present the time resolution measurements of the Lutetium-Yttrium Oxyorthosilicate (LYSO) calorimeter prototype for the Mu2e experiment. The measurements have been performed using the $e^-$ beam of the Beam Test Facility (BTF) in Frascati, Italy in the energy range from 100 to 400 MeV. The calorimeter prototype consisted of twenty five 30x30x130 mm$^3$, LYSO crystals read out by 10x10 mm$^2$ Hamamatsu Avalanche Photodiodes (APDs). The energy dependence of the measured time resolution can be parametrized as $\sigma_{t}(E)=a/\sqrt{E/\mathrm{GeV}} \oplus b$, with the stochastic and constant terms $a=(51\pm1)$ ps and $b=(10\pm4)$ ps, respectively. This corresponds to the time resolution of ($162\pm4$) ps at 100 MeV.