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arXiv · 1605.00941

e$^{+}$/e$^{-}$ Discrimination in Liquid Scintillator and Its Usage to Suppress $^{8}$He/$^{9}$Li Backgrounds

Ya-Ping Cheng·Liang-Jian Wen·Peng Zhang·Xing-Zhong Cao
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Abstract

Reactor neutrino experiments build large-scale detector systems to detect neutrinos. In liquid scintillator, a neutral bound state of a positron and an electron, named positronium, can be formed. The spin triplet state is called ortho-positronium (o-Ps). In this article, an experiment is designed to measure the lifetime of o-Ps, giving a result of 3.1 ns. A PSD parameter based on photon emission time distribution (PETD) was constructed to discriminate e$^+$/e$^-$. Finally, the application of e$^+$/e$^-$ discrimination in the JUNO experiment is shown. It helps suppress $^{8}$He/$^{9}$Li backgrounds and improves the sensitivity by 0.6 in $χ^2$ analysis with an assumption of $σ$=1 ns PMT Transit Time Spread, which will bring a smearing effect to the PETD.

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Ya-Ping Cheng, Liang-Jian Wen, Peng Zhang, Xing-Zhong Cao. 2016-09-14. e$^{+}$/e$^{-}$ Discrimination in Liquid Scintillator and Its Usage to Suppress $^{8}$He/$^{9}$Li Backgrounds. https://doi.org/10.1088/1674-1137%2F41%2F1%2F016101

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