First demonstration of a TES based cryogenic Li MoO detector for neutrinoless double beta decay search.

Area of Science:

• Particle Physics
• Experimental Physics
• Nuclear Physics

Background:

• Neutrinoless double-beta decay ($$) searches are crucial for understanding neutrino properties.
• Current cryogenic calorimetric experiments face challenges with scalability and background noise, particularly from event pile-up.

Purpose of the Study:

• To present a novel, mass-producible cryogenic detector concept for future neutrinoless double-beta decay experiments.
• To demonstrate a fast, low-impedance Transition-Edge Sensor (TES) based readout for Lithium Molybdate (Li $$ $$ MoO $$) absorbers.
• To evaluate the prototype detector's performance, including speed, energy resolution, and background mitigation capabilities.

Main Methods:

• Designed and constructed a prototype Li $$ $$ MoO $$ detector with a 2-cm side length and 21 g mass.
• Utilized a low-impedance TES-based readout for fast signal acquisition (rise-times $$ 0.5 ms).
• Operated the prototype at the NEXUS shallow underground facility and calibrated it up to the MeV energy region.

Main Results:

• Achieved a baseline energy resolution of 1.95 keV (FWHM).
• Demonstrated a detector speed more than one order of magnitude faster than current NTD-based detectors.
• Extrapolated pile-up background index to $$ ext{counts/keV/kg/yr} for CUPID-sized crystals.
• Measured fast O(20 ns) scintillation time constants in Li $$ $$ MoO $$.

Conclusions:

• The novel TES-based detector concept shows significant potential for future neutrinoless double-beta decay experiments.
• The fast readout effectively mitigates pile-up backgrounds, enhancing experimental sensitivity.
• The detector's performance and calibration range are suitable for high-precision $$ searches.