Tl₂LiYCl₆: Large Diameter, High Performing Dual Mode Scintillator

Abstract

Tl2LiYCl6:Ce (TLYC) is a recently discovered dual mode gamma-ray and neutron scintillator. So far small crystals of this composition have been studied, but for practical applications with affordable price, large-scale crystals are required. In this work, we present successful efforts to grow crack-free single crystals with sizes up to ⌀1″ × 5.5″. A variety of experimental techniques were employed to investigate the scintillation properties. A ⌀1″ × 1.2″ TLYC cylinder has a light yield of 25,000 ph/MeV, and its energy resolution is better than 4% at 662 keV. The gamma equivalent energy (GEE) produced by thermal neutron is 1.89 MeVee, along with a neutron induced light yield of 47,000 ph/n. Pulse shape discrimination (PSD) between gamma-rays and neutrons has been successfully shown with a current Figure-of-Merit (FOM) of 2.4. This article explores the crystal growth, scintillation properties, and potential applications of TLYC.

The crystal structure and temperature dependence of the elpasolite Tl2LiYCl6

“…In particular, recent studies have been investigating Tl 2 LiYCl 6 (TLYC) (Hawrami et al, 2016;Kim et al, 2016), a modification of the commercial standard, Cs 2 LiYCl 6 (CLYC) (Glodo et al, 2011). Substituting Tl + in place of Cs + improves detector performance by increasing the gamma stopping power while maintaining good scintillation performance (Hawrami et al, 2017). However, this introduction of Tl + also complicates the room-temperature crystal structure of TLYC, breaking the cubic symmetry present in CLYC.…”

Discovery, Crystal Growth, and Scintillation Properties of Novel Tl‐Based Scintillators

“…Also, recently, the n/γ discrimination capability of Tl 2 LiYCl 6 : Ce 3+ has been evaluated which is better than that of the commercial Cs 2 LiYCl 6 : Ce 3+ scintillator. [ 15 ] From the tables, one can expect better energy resolutions, i.e., less than 3% (FWHM) of the most Tl‐based scintillators at the obtained light yields. This might be due to the powder quality, i.e., level of impurities and crystal quality.…”

“…Our reported Tl 2 LiYCl 6 : Ce 3+[ 14 ] single crystal was recently studied by the Radiation Monitoring Devices, Inc. (RMD) and showed excellent scintillation properties than their commercially available counterpart, Cs 2 LiYCl 6 : Ce 3+ . [ 15 ] Very recently, we have reported Tl 2 HfCl 6 and Tl 2 ZrCl 6 intrinsic scintillators, these scintillators showed promising scintillation properties with excellent pulse shape discrimination capability.…”

New Intrinsic Scintillator with Large Effective Atomic Number: Tl2HfCl6 and Tl2ZrCl6 Crystals for X-ray and Gamma-ray Detections

“…Moreover, the TLYC crystal can distinguish gamma-ray and neutron radiations by pulse shape discrimination (PSD). (9) Presently, our group has also reported some new halide scintillator materials with low hygroscopicity and large Z eff values, namely, CsPbCl 3 , (10) Cs 3 BiCl 6 , (11) Rb 2 HfCl 6 , (12) TlMgCl 3 , (13) TlCdCl 3 , (14) and Cs 2 HfBr 6 . (15) In particular, Rb…”

“…(4,5) Other research groups studied various Tl-based alkali halide elpasolite scintillators activated with Ce 3+ . (6)(7)(8)(9) Among the elpasolite scintillators, the Tl 2 LiYCl 6 :Ce (TLYC) crystal shows good scintillation properties. Moreover, the TLYC crystal can distinguish gamma-ray and neutron radiations by pulse shape discrimination (PSD).…”