Advanced Inorganic Halide Ceramic Scintillators

TL;DR

This paper introduces a new equipment design and method for producing inorganic halide ceramic scintillators, achieving high energy resolution and brightness comparable to single crystals, with potential for lower-cost, scalable production.

Contribution

It presents optimized fabrication techniques for Cs2HfCl6 and Tl2HfCl6 ceramic scintillators, demonstrating their competitive performance with single crystal counterparts.

Findings

Energy resolution of 5.4% (CHC) and 5.1% (THC) at 662 keV

Light yields of 20,700 and 27,800 photons/MeV for CHC and THC

Decay times of sub-microsecond scale for both materials

Abstract

Research in ceramic scintillators has steadily progressed alongside the research in bulk single crystal scintillator growth. As interest in faster scintillation material production with lower cost increases, more research on scintillating ceramics is needed. Research targeting optimization of optically transparent ceramics that can rival bulk-grown crystals grown may lower cost, increase yield, increase volume, and improve energy resolution in applications and systems currently using sodium iodide and alike. Ceramic scintillators that are dense (>5 g/cm3), have high effective Z (>60), are bright (>40,000 photons/MeV), and are not sensitive to moisture as well as those that can be handled without protection are desired. Ultra-fast ceramic materials are also of interest. This paper presents an equipment design and technique to produce inorganic halide ceramic scintillators Cs2HfCl6 (CHC) and Tl2HfCl6 (THC). Improvements and optimization of CHC and THC ceramic scintillator fabrication are gauged by monitoring the energy resolution and peak position of 137Cs full energy peak at 662 keV. With a 1-inch diameter CHC ceramic scintillator, energy resolution of 5.4% (FWHM) and light yield of 20,700 ph/MeV are achieved, while with a 16-mm diameter THC ceramic scintillator, energy resolution of 5.1% (FWHM) and light yield of 27,800 ph/MeV are achieved. Decay times of 0.6 microseconds (21%) and 3.0 microseconds (79%) are measured for CHC and 0.3 microseconds (13%) and 1.0 microseconds (87%) for THC. Both ceramic CHC and THC scintillators have similarly good proportionality data when compared to their single crystal counterparts.