Li(2)(100depl)MoO(4) Scintillating Bolometers for Rare-Event Search Experiments

We report on the development of scintillating bolometers based on lithium molybdate crystals that contain molybdenum that has depleted into the double- [Formula: see text] active isotope [Formula: see text] Mo (Li [Formula: see text] [Formula: see text] MoO [Formula: see text]). We used two Li [Formula: see text] [Formula: see text] MoO [Formula: see text] cubic samples, each of which consisted of 45-millimeter sides and had a mass of 0.28 kg; these samples were produced following the purification and crystallization protocols developed for double- [Formula: see text] search experiments with [Formula: see text] Mo-enriched Li [Formula: see text] MoO [Formula: see text] crystals. Bolometric Ge detectors were utilized to register the scintillation photons that were emitted by the Li [Formula: see text] [Formula: see text] MoO [Formula: see text] crystal scintillators. The measurements were performed in the CROSS cryogenic set-up at the Canfranc Underground Laboratory (Spain). We observed that the Li [Formula: see text] [Formula: see text] MoO [Formula: see text] scintillating bolometers were characterized by an excellent spectrometric performance (∼3–6 keV of FWHM at 0.24–2.6 MeV [Formula: see text] s), moderate scintillation signal (∼0.3–0.6 keV/MeV scintillation-to-heat energy ratio, depending on the light collection conditions), and high radiopurity ([Formula: see text] Th and [Formula: see text] Ra activities are below a few µBq/kg), which is comparable with the best reported results of low-temperature detectors that are based on Li [Formula: see text] MoO [Formula: see text] using natural or [Formula: see text] Mo-enriched molybdenum content. The prospects of Li [Formula: see text] [Formula: see text] MoO [Formula: see text] bolometers for use in rare-event search experiments are briefly discussed.