Design and performance of SiPM-based readout of PbF2 crystals for high-rate, precision timing applications

TL;DR

This paper presents the design and testing of a SiPM-based readout system for PbF2 crystals in a high-rate, magnetic environment, enabling precise timing in the Muon g-2 experiment.

Contribution

It introduces an optimized SiPM readout design with custom electronics and demonstrates its performance through bench and beam tests for high-rate timing applications.

Findings

High quantum efficiency achieved

Gain stability under varying rates confirmed

Effective pulse shape preservation in tests

Abstract

We have developed a custom amplifier board coupled to a large-format 16-channel Hamamatsu silicon photomultiplier device for use as the light sensor for the electromagnetic calorimeters in the Muon g-2 experiment at Fermilab. The calorimeter absorber is an array of lead-fluoride crystals, which produces short-duration Cherenkov light. The detector sits in the high magnetic field of the muon storage ring. The SiPMs selected, and their accompanying custom electronics, must preserve the short pulse shape, have high quantum efficiency, be non-magnetic, exhibit gain stability under varying rate conditions, and cover a fairly large fraction of the crystal exit surface area. We describe an optimized design that employs the new-generation of thru-silicon via devices. The performance is documented in a series of bench and beam tests.