Bright Eu2+-activated polycrystalline ceramic neutron scintillators

C. L. Wang, M. P. Paranthaman, R. A. Riedel, J. P. Hodges, J. J. Karlic, R. A. Veatch, L. Li, C. A. Bridges

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Scintillation properties of Eu2+-doped CaF2-AlF3-6LiF (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 a 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 lead to the formation of electron trapping centers in Eu:CaF2 and the Li3AlF6 phase is formed, which reduces the light output. A neutron–gamma-discrimination (NGD) ratio of 9×108 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. Our results suggest that Eu:CALF scintillators can potentially replace the GS20 scintillator used for thermal and cold neutron detection systems.

Funding

We acknowledge experimental help from D. Cornelius, B.W. Hannan, C.A. Montcalm, and T. Visscher, and comments on this manuscript made by K.W. Herwig. This work was partly supported by Laboratory Directed R&D (LDRD) of ORNL , and by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy . Research of CAB and MPP was sponsored by Materials Sciences and Engineering Division, Office of Basic Energy Science, US Department of Energy .

FundersFunder number
ORNL Laboratory Research and Development Program
Scientific User Facilities Division
U.S. Department of Energy
Basic Energy Sciences
Oak Ridge National Laboratory
Division of Materials Sciences and Engineering

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