Novel Microcomposite Scintillator Films for Thermal-Neutron Detection

C. L. Wang, M. P. Paranthaman, R. A. Riedel, R. A. Veatch, V. Yildirim

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Scopus citations

Abstract

Neutron scintillator films composed of a Eu2+-doped CaF2-AlF3-6LiF (Eu:CALF) polycrystalline ceramic powder and a poly(vinylidene fluoride) (PVDF) polymer matrix have been fabricated for neutron position-sensitive detectors (n-PSDs). Scintillation light yield and neutron detection efficiency have been measured as a function of film thickness (L) in the range of L=0.08-1.0 mm. The light yields of the films are 17,000-19,000 photons per thermal neutron. Based on a photon diffusion model in disordered media, the mean-free path of scintillation photons is 1.25±0.35 mm. Light emission cone size, the Full-width-at-half-maximum (FWHM) of spatial distribution of emitted light, is expected to increase with the film thickness. There is a large difference in the longest lifetime component (~800 ns) between neutron and gamma events at L≦0.39 mm, but this difference diminishes for films thicker than 0.39 mm, making neutron-gamma-discrimination (NGD) harder for these thicker films. The NGD ratio, or neutron-gamma-efficiency ratio, has been estimated using primitive digital-signal processing and machine-learning algorithms for a 1.0-mm-thick film. It reaches (2-3) x 105 using Principle Component Analysis (PCA) and 2-feature based pulse-shape discrimination methods, but they give a low thermal-neutron detection efficiency (~10%). A conventional Nonnegative Matrix Factorization (NMF) and a Graph-regularized NMF (GNMF) algorithms generate NGD ratios of 1 x 107 and 8 x108, and thermal-neutron detection efficiencies of 15 and 37%, respectively. Potential applications of our microcomposite scintillation films include neutron scattering for materials research, and neutron imaging and spectroscopy for nondestructive testing and security.

Original languageEnglish
Title of host publication2020 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2020
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781728176932
DOIs
StatePublished - 2020
Event2020 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2020 - Boston, United States
Duration: Oct 31 2020Nov 7 2020

Publication series

Name2020 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2020

Conference

Conference2020 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2020
Country/TerritoryUnited States
CityBoston
Period10/31/2011/7/20

Funding

Manuscript received Nov. 16, 2020. This work was supported by Key-Area Research and Development Program of Guangdong Province, China (2020B0303090001), and by Laboratory Directed R&D (LDRD) fund of ORNL, and by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy.

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