Ultraviolet cross-luminescence in ternary chlorides of alkali and alkaline-earth metals

TL;DR

This paper explores ultraviolet cross-luminescence in cesium-based ternary chlorides, highlighting their potential as fast, efficient scintillators suitable for medical imaging and high-energy physics applications.

Contribution

It introduces cesium-based ternary chlorides as promising new CL scintillators with spectral properties aligned to modern photodetectors, addressing previous limitations.

Findings

Cesium-based ternary chlorides exhibit UV cross-luminescence.

They offer a red-shifted emission suitable for UV-sensitive detectors.

These materials maintain high light output and fast timing characteristics.

Abstract

After the discovery of a cross-luminescence (CL) in BaF2 in 1982, a large number of CL scintillators were investigated. However, no CL scintillator superior to BaF2 has been discovered, and the research of CL scintillators has subsided. Recent technological development in medical imaging and high-energy physics created a new demand for ultra-fast scintillators further supported by the development of UV-sensitive semiconductor photodetectors. As a consequence, renewed interest in CL scintillators appeared. To satisfy the requirements of fast timing applications high photo-detection efficiency, e. i. a good spectral match between the scintillator and photodetector must be achieved. Cesium-based ternary chlorides could provide a red-shift (~1.5 eV) of CL towards the sensitive region of the photodetector (PMT or SiPM) while keeping light output and timing characteristics comparable to BaF2.