Luminescence and scintillation properties of Rb₂HfCl₆ crystals

Abstract

We developed a scintillator based on a Rb2HfCl6 crystal as a ternary halide crystal with intrinsic luminescence. In the photoluminescence spectra, two emission bands are observed at 383 and 434 nm. The 434 nm emission band for Rb2HfCl6 may be attributed to [HfCl6]2− complex ion or [ZrCl6]2− impurity, since the Rb2HfCl6 contained Zr as impurity at 0.62 mol %. The radioluminescence band is observed at 420 nm and can be attributed to the same origin as the photoluminescence band at 434 nm. The scintillation decay-time constants were 0.84 and 5.4 µs. The light yield was estimated to be 24,100 photons/MeV.

Inorganic scintillating materials and scintillation detectors

“…With the knowledge of a similar compound, Cs 2 ZrCl 6 , the emission origin was blamed for the charge-transfer luminescence of the [HfCl 6 ] 2− anion complex. Motivated by this work, we have further developed non-hygroscopic halide scintillators, including Tl- and In-doped CsCl, 119) TlCdCl 3 , 120) Tl- and Ce-doped Cs 2 HfCl 6 , 121) Rb 2 HfCl 6 , 122) Ce-doped CsCaCl 3 123) and TlMgCl 3 . 124) Among these newly developed scintillators, especially TlMgCl 3 shows the most promising properties of a high light yield (46,000 ph/MeV), a high energy resolution (5% at 662 keV) and a relatively fast decay (60 ns).…”

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

“…The slight shift in emission wavelength may be due to the difference in the monovalent cation between Cs + and Tl + since a similar emission shift was observed previously for Cs 2 HfCl 6 and Rb 2 HfCl 6 . (12) The scintillation decay profiles of Tl 2 HfCl 6 and Tl 2 ZrCl 6 crystals are shown in Figs. 5(a) and 5(b), respectively.…”

“…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…”

Mild Hydrothermal Synthesis of the Complex Hafnium-Containing Fluorides Cs2[M(H2O)6][Hf2F12] (M = Ni, Co, Zn), CuHfF6(H2O)4, and Cs2Hf3Mn3F20 Based on HfF7 and HfF6 Coordination Polyhedra

“…For example, the luminescent properties of hafnium-based alkali fluorides, Li 2 HfF 6 , Na 5 Hf 2 F 13 , K 3 HfOF 5 and K 2 Hf 3 OF 12 , depend on a variety of factors including the alkali cation size, the presence or absence of oxygen in the compound, and the coordination environment of the hafnium atoms . Similar effects have been observed in inorganic hybrid materials containing transition-metal complex cations that exhibit efficient photocatalytic activity. − Hafnium halides, such as Cs 2 HfCl 6 and Rb 2 HfCl 6 , exhibit a remarkable structural versatility, are promising materials for a number of optical applications, and have been shown to exhibit intrinsic luminescence along with excellent scintillation properties. − Kang and Biswas have investigated hafnium chlorides and employed quantum chemistry calculations to demonstrate that the absorption and luminescence processes are highly dependent on the [HfCl 6 ] 2– charge-transfer transition . It is possible that similar processes could exist in [HfF 6 ] 2– units.…”