e+/e- discrimination in liquid scintillator and its usage to suppress 8He/9Li backgrounds
- Received Date: 2016-04-15
- Accepted Date: 2016-07-27
- Available Online: 2017-01-05
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 8He/9Li backgrounds and improves the sensitivity by 0.6 in χ2 analysis with an assumption of σ=1 ns PMT Transit Time Spread, which will bring a smearing effect to the PETD.