Design and beam-test characterization of the CRILIN semi-homogeneous crystal calorimeter
arXiv:2607.28477
The paper describes the construction and beam‑test performance of the CRILIN semi‑homogeneous electromagnetic calorimeter, which uses PbF₂ crystal matrices read out by UV‑extended silicon photomultipliers, achieving sub‑50 ps timing and high energy resolution for electrons up to 120 GeV.
Abstract
CRILIN is a high-granularity semi-homogeneous electromagnetic calorimeter based on longitudinally segmented PbF crystal matrices read out by UV-extended silicon photomultipliers. The concept combines fast Cherenkov response, fine transverse granularity, longitudinal shower information, and radiation tolerance for future lepton-collider experiments. This paper reports the construction of a large-area prototype and its performance measured in beam tests at the CERN SPS. The detector comprises five PbF crystal matrices, has a depth of about , and is read out by four SiPMs per crystal integrated in a single electronic channel. Electron data between 10 and 120~GeV and dedicated 150~GeV muon data were used to characterize the detector response. A time resolution below 50~ps is achieved for electron energies above 10~GeV, reaching values below 20~ps above 60~GeV. The energy resolution is described by a stochastic term of and a constant term of , with an additional noise contribution fixed from pedestal data. The longitudinal segmentation enables event-by-event corrections based on the reconstructed shower development, resulting in a significant improvement of the energy resolution. A light yield of approximately 0.54~photoelectrons/MeV is measured consistently using both electron showers and minimum-ionizing particles. A Geant4-based simulation incorporating the relevant experimental effects reproduces the measured energy resolution. These results validate the CRILIN architecture as a compact, fast, and longitudinally segmented electromagnetic calorimeter for future collider experiments.