High-granularity crystal calorimetry: conceptual designs and first studies

A new concept of high-granularity calorimetry based on crystals has been proposed for future lepton collider experiments, e.g. the Circular Electron Positron Collider (CEPC), with an aim to reach an optimal energy resolution as well as 3D-positioning precision. In this conceptual design, crystals are finely segmented in both transverse and longitudinal directions. Each crystal is optically isolated and read out by a compact semiconductor photosensor (e.g. silicon photomultiplier, SiPM). Simulation models are developed to study the expected performance of the whole calorimeter as well as the readout scheme of a single crystal. Cosmic-ray measurements have been made with a single crystal bar of lead tungstate. First tests with a new front-end electronics chip for the SiPM readout are also presented.