Characterization of positronium properties in doped liquid scintillators

Abstract

Ortho-positronium (o-Ps) formation and decay can replace the annihilation process, when positron interacts in liquid scintillator media. The delay induced by the positronium decay represents either a potential signature for anti-neutrino detection, via inverse beta decay, or to identify and suppress positron background, as recently demonstrated by the Borexino experiment. The formation probability and decay time of o-Ps depend strongly on the surrounding material. In this paper, we characterize the o-Ps properties in liquid scintillators as function of concentrations of gadolinium, lithium, neodymium, and tellurium, dopers used by present and future neutrino experiments. In particular, gadolinium and lithium are high neutron cross section isotopes, widely used in reactor anti-neutrino experiments, while neodymium and tellurium are double beta decay emitters, employed to investigates the Majorana neutrino nature. Future neutrino experiments may profit from the performed measurements to tune the preparation of the scintillator in order to maximize the o-Ps signature, and therefore the discrimination power.

arXiv comment6 pages, 7 figures

References in corpus (6)

• The Borexino detector at the Laboratori Nazionali del Gran Sasso
• Measurement of the solar 8B neutrino rate with a liquid scintillator target and 3 MeV energy threshold in the Borexino detector
• First evidence of pep solar neutrinos by direct detection in Borexino
• Precision Study of Positronium: Testing Bound State QED Theory
• Fast Neutron Detection with 6Li-loaded Liquid Scintillator
• Positronium signature in organic liquid scintillators for neutrino experiments

Cited by in corpus (7)

• Ortho-positronium observation in the Double Chooz Experiment
• Multi-site Event Discrimination in Large Liquid Scintillation Detectors
• Particle Identification at MeV Energies in JUNO
• Measurements of the Lifetime of Orthopositronium in the LAB-Based Liquid Scintillator of JUNO
• A new anti-neutrino detection technique based on positronium tagging with plastic scintillators
• Measurement of ortho-Positronium Properties in Liquid Scintillators
• e${}^{+}$/e${}^{-}$ Discrimination in Liquid Scintillator and Its Usage to Suppress ${}^8$He/${}^9$Li Backgrounds