Radiogenic neutron background in reactor neutrino experiments

Abstract

We report a novel correlated background in the antineutrino detection using the inverse beta decay reaction. Spontaneous fissions and $(\alpha ,n)$ reactions in peripheral materials of the antineutrino detector, such as borosilicate glass of photomultipliers, produce fast neutrons and prompt gamma rays. If the shielding from the material to the detector target were not thick enough, neutrons and gammas could enter the target volume and mimic antineutrino signals. This paper revisits the yields and energy spectra of neutrons produced in B$(\alpha ,n)$N and F$(\alpha ,n)$Na reactions. A Geant4 based simulation has been carried out using a simplified detector geometry for the present generation reactor neutrino experiments. The background rates in these experiments are estimated. If this background was not taken into account, the value of the neutrino mixing angle ${\sin }^{2}2{\theta }_{13}$ would be underestimated. We recommend that Daya Bay, RENO, Double Chooz, and JUNO, carefully examine the masses and radiopurity levels of detector materials that are close to the target and rich in boron and fluorine.

arXiv comment11 pages, 9 figures, 5 tables

References in corpus (12)

• Observation of electron-antineutrino disappearance at Daya Bay
• Observation of Reactor Electron Antineutrino Disappearance in the RENO Experiment
• Indication for the disappearance of reactor electron antineutrinos in the Double Chooz experiment
• Neutrino Physics with JUNO
• Combined Analysis of all Three Phases of Solar Neutrino Data from the Sudbury Neutrino Observatory
• The Detector System of The Daya Bay Reactor Neutrino Experiment
• Improved measurement of ${}^8$B solar neutrinos with 1.5 kt y of Borexino exposure
• Radiogenic Neutron Yield Calculations for Low-Background Experiments
• New measurement of ${\theta }_{13}$ via neutron capture on hydrogen at Daya Bay
• Neutron production induced by $\alpha$-decay with Geant4
• Input Comparison of Radiogenic Neutron Estimates for Ultra-low Background Experiments
• Background Evaluation for the Neutron Sources in the Daya Bay Experiment

Cited by in corpus (2)

• Sub-percent Precision Measurement of Neutrino Oscillation Parameters with JUNO
• Experimental study of 13C(α,n)16O reactions in the Majorana Demonstrator calibration data