A highly-compact and ultra-fast homogeneous electromagnetic calorimeter based on oriented lead tungstate crystals

Abstract

Progress in high-energy physics has been closely tied to the development of highperformance electromagnetic calorimeters. Recent experiments have demonstrated the possibility to significantly accelerate the development of electromagnetic showers inside scintillating crystals typically used in homogeneous calorimeters based on scintillating crystals when the incident beam is aligned with a crystallographic axis to within a few mrad. In particular, a reduction of the radiation length has been measured when ultrarelativistic electron and photon beams were incident on a high-Z scintillator crystal along one of its main axes. Here, we propose the possibility to exploit this physical effect for the design of a new type of compact e.m. calorimeter, based on oriented ultrafast lead tungstate (PWO-UF) crystals, with a significant reduction in the depth needed to contain electromagnetic showers produced by high-energy particles with respect to the state-of-the-art. We report results from tests of the crystallographic quality of PWO-UF samples via high-resolution X-ray diffraction and photoelastic analysis. We then describe a proof-of-concept calorimeter geometry defined with a Geant4 model including the shower development in oriented crystals. Finally, we discuss the experimental techniques needed for the realization of a matrix of scintillator crystals oriented along a specific crystallographic direction. Since the angular acceptance for e.m. shower acceleration depends little on the particle energy, while the decrease of the shower length remains pronounced at very high energy, an oriented crystal calorimeter will open the way for applications at the maximum energies achievable in current and future experiments. Such applications span from forward calorimeters, to compact beam dumps for the search for light dark matter, to source-pointing space-borne γ-ray telescopes.

References in corpus (7)

• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• The DArk Matter Particle Explorer mission
• Dark matter search in missing energy events with NA64
• Strong reduction of the effective radiation length in an axially oriented scintillator crystal
• Investigation on radiation generated by Sub-GeV electrons in ultrashort Si and Ge bent crystals
• Silicon crystals for steering of high-intensity particle beams at ultra-high energy accelerators
• Characterization of a defective PbWO4 crystal cut along the a-c crystallographic plane: structural assessment and a novel photoelastic stress analysis

Cited by in corpus (4)

• Investigation of Radiation Emitted by Sub GeV Electrons in Oriented Scintillator Crystals
• High-Precision Alignment Techniques for Realizing an Ultracompact Electromagnetic Calorimeters Using Oriented high-Z Scintillator Crystals
• Particle identification capability of a homogeneous calorimeter composed of oriented crystals
• R&D on a high-performance electromagnetic calorimeter based on oriented crystalline scintillators