Bright ${\mathrm{Eu}}^{2+}$ -activated polycrystalline ceramic neutron scintillators

Journal Article · Wed Nov 22 00:00:00 EST 2017 · Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment

DOI:https://doi.org/10.1016/j.nima.2017.11.013· OSTI ID:1412058

Wang, Cai -Lin  ^[1]; Paranthaman, M. Parans  ^[1]; Riedel, Richard A. ^[1]; Hodges, Jason P.  ^[1]; Karlic, John J. ^[1]; Veatch, Ryan A. ^[1]; Li, Ling  ^[1]; Bridges, Craid A.  ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Scintillation properties of Eu²⁺-doped CaF_2-AlF_3-⁶LiF (Eu:CALF) polycrystalline ceramic thermal-neutron scintillators as a function of AlF₃ concentration have been studied. The emission band peaked at a wavelength of 425-431 nm is due to the presence of Eu:CaF₂ micro-crystallites. The highest light output from these samples is approximately 20,000 photons per thermal neutron, which is 3 times that of a GS20 ⁶Li-glass scintillator. The pulse-decay lifetime and light output vs. AlF₃ concentration may be understood using a radiation trapping model and the formation of Li₃AlF₆ phase. At lower AlF₃ concentration, Al³⁺ ions in Eu:CaF₂ passivate the hole-trapping defects and enhance the light output; whereas at higher AlF₃ concentration, Al³⁺ ions act as electron-trapped defects in Eu:CaF₂ and the Li₃AlF₆ phase is formed, which reduces the light output. A neutron-gamma-discrimination (NGD) ratio of 9 x 10⁸ was obtained from Principal Component Analysis (PCA) of digital waveforms, while Fisher Linear Discriminant Analysis (FLDA) can completely separate the thermal neutrons from ⁶⁰Co gamma rays within the limit of gamma event statistics used in this work. Lastly, our results suggest that Eu:CALF scintillators can potentially replace the GS20 scintillator used for thermal and cold neutron detection systems.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1412058
• Journal Information: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 883, Issue C; ISSN 0168-9002
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

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