Measurement of time resolution of the Mu2e LYSO calorimeter prototype

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.Comment: 18 pages, 14 figures, accepted for the journal Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipmen

The Detectors of the Mu2e Experiment

“…A long R&D phase with small prototypes demonstrates that the calorimeter design easily satisfies the requirements [7][8][9][10]. Pre-production components have been used to build a large size calorimeter prototype, Module-0 (Fig.…”

Design and Status of the Mu2e Crystal Calorimeter

“…After a long R&D program [8], [9], [10], [11], a final downselect of the scintillating crystal and photosensor has been done. Undoped CsI crystals were chosen as the best compromise between cost, performance and reliability.…”

Final design and current status of the Mu2e crystal calorimeter

“…To have a redundant system, each crystal is readout by two photosensors that must be able to independently collect the light. After a long R&D program [3][4], the discussed requirements pushed the experiment to adopt a calorimeter made of undoped CsI crystals optically coupled to 14×20 mm 2 large area UV-extended SiPMs. The final calorimeter design consists of two matrices of 674 un-doped CsI crystals each coupled to two SiPMs and arranged in two disks as shown in Figure 1.…”