Multi-site event discrimination in large liquid scintillation detectors

Abstract

Simulation studies have been carried out to explore the ability to discriminate between single-site and multi-site energy depositions in large scale liquid scintillation detectors. A robust approach has been found that is predicted to lead to a significant statistical separation for a large variety of event classes, providing a powerful tool to discriminate against backgrounds and break important degeneracies in signal extraction. This has particularly relevant implications for liquid scintillator searches for neutrinoless double beta decay (0νββ) from 130 Te and 136 Xe, where it is possible for a true 0νββ signal to be distinguished from most radioactive backgrounds (including those from cosmogenic production) as well as unknown gamma lines from the target isotope.1 The detector geometry closely matches the SNO+ detector but the number of functioning PMTs and the exact scintillator model will differ.2 collection efficiency × quantum efficiency 3 the pre-pulsing and after-pulsing behaviour is the same as the R1408.

Theia: an advanced optical neutrino detector

“…These efforts include a precision measurement of attenuation at long distances, demonstration of material compatibility with detector components, and accurate costs and production capabilities. Examples include WbLS development at BNL [29], compatibility studies at UC Davis, characterization and optimization with the CHESS detector at UC Berkeley and LBNL [23,30], fast photon sensor development at Chicago and Iowa State [31], spectral photon sorting at Penn [26], development of reconstruction and particle identification algorithms [32][33][34][35][36][37][38][39][40], and potential nanoparticle loading in NuDot at MIT [41]. A practical purification system is being developed at UC Davis [42].…”

“…This includes possibilities for particle identification at energies as low as a few MeV based on topological information. For example it is now possible to distinguish point-like events from multi-site events in liquid scintillator [35] using various techniques, including likelihood-based pulse shape discrimination methods [36]. Figure 3 shows an example of the separation of electrons from gammas, critical for separation of neutrino scatters, which produce electrons, from common gamma emitters in the uranium and thorium decay chains.…”

Cherenkov and scintillation separation in water-based liquid scintillator using an LAPPDTM

“…Additionally, both the improved timing and pixelation of LAPPDs lead to enhanced vertex reconstruction in larger detectors. This leads to improved PID, such as distinguishing e − events from e + , γ , or α particles [44]. Studies for the ANNIE detector have shown that the introduction of five LAPPDs (to a baseline design of 125 PMTs) enhances vertex resolution from about Fig.…”

The Future of Solar Neutrinos

“…Substantial work has been dedicated to realizing this concept, both experimentally (218)(219)(220)(221)(222) and in the development of new analysis tools to leverage and enhance this simultaneous detection for large detectors (223)(224)(225)(226)(227)(228)(229).…”