The CUPID-Mo experiment for neutrinoless double-beta decay: performance and prospects
Résumé
CUPID-Mo is a bolometric experiment to search for neutrinoless double-beta decay ($0\nu \beta \beta $) of $^{100}\hbox {Mo}$. In this article, we detail the CUPID-Mo detector concept, assembly and installation in the Modane underground laboratory, providing results from the first datasets. The CUPID-Mo detector consists of an array of 20 $^{100}\hbox {Mo}$-enriched 0.2 kg $\hbox {Li}_2\hbox {MoO}_4$ crystals operated as scintillating bolometers at $\sim 20\hbox { mK}$. The $\hbox {Li}_2\hbox {MoO}_4$ crystals are complemented by 20 thin Ge optical bolometers to reject $\alpha $ events by the simultaneous detection of heat and scintillation light. We observe a good detector uniformity and an excellent energy resolution of 5.3 keV (6.5 keV) FWHM at 2615 keV, in calibration (physics) data. Light collection ensures the rejection of $\alpha $ particles at a level much higher than 99.9% – with equally high acceptance for $\gamma $/$\beta $ events – in the region of interest for $^{100}\hbox {Mo}0\nu \beta \beta $. We present limits on the crystals’ radiopurity: $\le 3~\mu \hbox {Bq/kg}$ of $^{226}\hbox {Ra}$ and $\le 2~\mu \hbox {Bq/kg}$ of $^{232}\hbox {Th}$. We discuss the science reach of CUPID-Mo, which can set the most stringent half-life limit on the $^{100}\hbox {Mo}0\nu \beta \beta $ decay in half-a-year’s livetime. The achieved results show that CUPID-Mo is a successful demonstrator of the technology developed by the LUMINEU project and subsequently selected for the CUPID experiment, a proposed follow-up of CUORE, the currently running first tonne-scale bolometric $0\nu \beta \beta $ experiment.
Mots clés
Double-beta decay
Cryogenic detector
Scintillating bolometer
Scintillator
Enriched materials
100 Mo
Lithium molybdate
High performance
Particle identification
Radiopurity
Low background
double-beta decay: (0neutrino)
detector: design
germanium: detector
bolometer
scintillation counter
photon: yield
energy resolution
crystal
lithium
molybdenum: oxygen
molybdenum: nuclide
calibration
performance
particle identification
bibliography
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