The next generation of crystal detectors

Abstract

Background: In high-energy and nuclear physics experiments, total absorption electromagnetic calorimeters made of inorganic crystals are known for their superb energy resolution and detection efficiency for photon and electron measurements. A crystal calorimeter is thus the choice for those experiments where precision measurements of photons and electrons are crucial for their physics missions. It is also known that the existing crystal detectors are neither bright nor fast enough nor radiation hard enough to survive severe radiation environment expected in future HEP experiments. Crystal detectors have also been proposed to build a homogeneous hadron calorimeter to achieve unprecedented jet mass resolution by duel readout of both Cherenkov and scintillation light, where the development of cost-effective crystal detectors is a crucial issue because of the 100 cubic meters crystal volume required. Purpose: To develop novel inorganic crystal scintillator-based detector concepts for future HEP experiments at the energy and intensity frontiers. Methods: Optical and scintillation properties of novel inorganic crystal scintillators, such as excitation, emission and transmittance spectra, light output and decay time, are characterized before and after irradiation by ionization dose and hadrons. Their performance and radiation hardness are compared to the requirements, and feedback is given to the crystal manufacturers for quality improvement. Results: As a result of this investigation, several inorganic crystal scintillator-based detector concepts are established for future HEP experiments, such as an LSO/LYSO crystal-based total absorption and/or sampling calorimeter concept, a barium fluoride crystal-based very fast crystal calorimeter concept, and a cost-effective inorganic scintillator-based homogeneous hadron calorimeter concept. Conclusion: Bright, fast and radiation hard LYSO/LSO crystals may be used for a total absorption ECAL. An LYSO/W Shashlik sampling calorimeter will survive the harsh radiation environment expected at the HL-LHC. With sub-ns decay time of its fast scintillation component and excellent radiation hardness, barium fluoride crystals would provide more than ten times faster rate and timing capability, provided that their slow scintillation component is effectively suppressed to avoid pileup. PbF2, PbFCl and BSO crystals may provide a foundation for a homogeneous hadron calorimeter with dual readout for both Cherenkov and scintillation light to achieve unprecedented jet mass resolution for future lepton colliders.

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