Aboveground test of an advanced Li${}_2$MoO${}_4$ scintillating bolometer to search for neutrinoless double beta decay of ${}^{100}$Mo

Abstract

Large lithium molybdate (Li${}_2$MoO${}_4$) crystal boules were produced by using the low thermal gradient Czochralski growth technique from deeply purified molybdenum. A small sample from one of the boules was preliminary characterized in terms of X-ray-induced and thermally-excited luminescence. A large cylindrical crystalline element (with a size of $\oslash 40\times 40$ mm) was used to fabricate a scintillating bolometer, which was operated aboveground at $\sim 15$ mK by using a pulse-tube cryostat housing a high-power dilution refrigerator. The excellent detector performance in terms of energy resolution and $\hat{I}\pm$ background suppression along with preliminary positive indications on the radiopurity of this material show the potentiality of Li${}_2$MoO${}_4$ scintillating bolometers for low-counting experiment to search for neutrinoless double beta decay of ${}^{100}$Mo.