Development of -containing scintillating bolometers for a high-sensitivity neutrinoless double-beta decay search

Area of Science:

• Nuclear Physics
• Particle Physics
• Experimental Physics

Background:

• Neutrinoless double-beta decay is a hypothetical process crucial for understanding neutrino properties and matter-antimatter asymmetry.
• Bolometric detectors offer a promising approach for sensitive searches due to their large detection mass and excellent energy resolution.
• The CUPID (Cupboard) experiment aims to search for this decay using an array of cryogenic detectors.

Purpose of the Study:

• To develop and characterize enriched scintillating bolometers for the CUPID experiment.
• To demonstrate the potential of these detectors for high-sensitivity neutrinoless double-beta decay searches.
• To measure the two-neutrino double-beta decay half-life of Molybdenum-100.

Main Methods:

• Production of large-mass, high-optical quality, radiopure zinc and lithium molybdate crystals enriched with Molybdenum-100.
• Development of high-performance single detector modules using these crystals (0.2-0.4 kg scintillating bolometers).
• Characterization of detector performance, including energy resolution, background rejection, and impurity levels (e.g., Lead-210, Lead-214, Bismuth-214).

Main Results:

• Lithium molybdate detectors achieved an energy resolution of 4-6 keV FWHM near the Q-value of Molybdenum-100's double-beta decay (3034 keV).
• Background rejection from alpha particles (e.g., from Lead-210) above 2.6 MeV exceeded 99.9%.
• Measured the two-neutrino double-beta decay half-life of Molybdenum-100 with high accuracy: [6.90 ± 0.15(stat.) ± 0.37(syst.)] x 10^19 years.

Conclusions:

• Enriched scintillating bolometers, particularly lithium molybdate, are well-suited for neutrinoless double-beta decay searches.
• The developed technology and crystal production methods meet the stringent requirements for next-generation experiments like CUPID.
• Lithium molybdate has been selected for the CUPID-0/Mo demonstrator, highlighting its technological readiness.