Design, status and perspective of the Mu2e crystal calorimeter

TL;DR

The paper discusses the design, development, and current status of the Mu2e crystal calorimeter, emphasizing its robustness in harsh environments and its role in particle discrimination and triggering for the Mu2e experiment.

Contribution

It presents the detailed design and recent R&D results of the Mu2e crystal calorimeter, highlighting innovations for operation in high-radiation and magnetic field conditions.

Findings

Calorimeter designed to withstand 10 krad/year radiation

Achieved effective mu/e separation capabilities

Demonstrated suitability for high magnetic field environments

Abstract

The Mu2e experiment at Fermilab will search for the charged lepton flavor violating process of neutrino-less $\mu \to e$ coherent conversion in the field of an aluminum nucleus. Mu2e will reach a single event sensitivity of about $2.5\cdot 10^{-17}$ that corresponds to four orders of magnitude improvements with respect to the current best limit. The detector system consists of a straw tube tracker and a crystal calorimeter made of undoped CsI coupled with Silicon Photomultipliers. The calorimeter was designed to be operable in a harsh environment where about 10 krad/year will be delivered in the hottest region and work in presence of 1 T magnetic field. The calorimeter role is to perform $\mu$/e separation to suppress cosmic muons mimiking the signal, while providing a high level trigger and a seeding the track search in the tracker. In this paper we present the calorimeter design and the latest R$\&$D results.