Enriched TeO$_2$ bolometers with active particle discrimination: towards the CUPID experiment

• Main Authors: Artusa, D. R, AvignoneIII, F. T, Beeman, J. W, Dafinei, I, Dumoulin, L, Ge, Z, Giuliani, A, Gotti, C, de Marcillac, P, Marnieros, S, Nagorny, S, Nisi, S, Nones, C, Norman, E. B, Novati, V, Olivieri, E, Orlandi, D, Pagnanini, L, Pattavina, L, Pessina, G, Pirro, S, Poda, D. V, Rusconi, C, Schäffner, K, Scielzo, N. D, Zhu, Y
• Format: Journal Article
• Language: English
• Published: 10.10.2016
• Subjects: Physics - Instrumentation and Detectors; Physics - Nuclear Experiment
• DOI: 10.48550/arxiv.1610.03513

Phys Lett B 2017 We present the performances of two 92% enriched $^{130}$TeO$_2$ crystals operated as thermal bolometers in view of a next generation experiment to search for neutrinoless double beta decay of $^{130}$Te. The crystals, 435 g each, show an energy resolution, evaluated at the 2615 keV $\gamma$-line of $^{208}$Tl, of 6.5 and 4.3 keV FWHM. The only observable internal radioactive contamination arises from $^{238}$U (15 and 8 $\mu$Bq/kg, respectively). The internal activity of the most problematic nuclei for neutrinoless double beta decay, $^{226}$Ra and $^{228}$Th, are both evaluated as $<$3.1 $\mu$Bq/kg for one crystal and $<$2.3 $\mu$Bq/kg for the second. Thanks to the readout of the weak Cherenkov light emitted by $\beta/\gamma$ particles by means of Neganov-Luke bolometric light detectors we were able to perform an event-by-event identification of $\beta/\gamma$ events with a 95% acceptance level, while establishing a rejection factor of 98.21% and 99.99% for $\alpha$ particles.