Rejection of randomly coinciding events in ZnMoO${}_4$ scintillating bolometers

Abstract

Random coincidence of events (particularly from two neutrino double beta decay) could be one of the main sources of background in the search for neutrinoless double beta decay with cryogenic bolometers due to their poor time resolution. Pulse-shape discrimination by using front edge analysis, mean-time and ${\chi }^2$ methods was applied to discriminate randomly coinciding events in ZnMoO${}_4$ cryogenic scintillating bolometers. These events can be effectively rejected at the level of 99% by the analysis of the heat signals with rise-time of about 14 ms and signal-to-noise ratio of 900, and at the level of 92% by the analysis of the light signals with rise-time of about 3 ms and signal-to-noise ratio of 30, under the requirement to detect 95% of single events. These rejection efficiencies are compatible with extremely low background levels in the region of interest of neutrinoless double beta decay of ${}^{100}$Mo for enriched ZnMoO${}_4$ detectors, of the order of $10^{-4}$ counts/(y keV kg). Pulse-shape parameters have been chosen on the basis of the performance of a real massive ZnMoO${}_4$ scintillating bolometer. Importance of the signal-to-noise ratio, correct finding of the signal start and choice of an appropriate sampling frequency are discussed.

References in corpus (4)

• Double Beta Decay, Majorana Neutrinos, and Neutrino Mass
• Performance of ZnMoO4 crystal as cryogenic scintillating bolometer to search for double beta decay of molybdenum
• Recent Progress in Double Beta Decay
• Random coincidence of $2\nu 2\beta$ decay events as a background source in bolometric $0\nu 2\beta$ decay experiments

Cited by in corpus (10)

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• A first test of CUPID prototypal light detectors with NTD-Ge sensors in a pulse-tube cryostat
• Twelve-crystal prototype of Li${}_2$MoO${}_4$ scintillating bolometers for CUPID and CROSS experiments
• A novel mechanical design of a bolometric array for the CROSS double-beta decay experiment
• BINGO innovative assembly for background reduction in bolometric $0\nu \beta \beta$ experiments
• Cryogenic light detectors with thermal signal amplification for $0\nu \beta \beta$ search experiments