Enriched TeO\(_2\) bolometers with active particle discrimination: towards the CUPID experiment

• Published in: arXiv.org
• Main Authors: Artusa, D R, Avignone, F T, Beeman, J W, Dafinei, I, Dumoulin, L, Z Ge, 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: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 10.10.2016
• Subjects: Alpha rays; Beta decay; Beta rays; Bolometers; Crystals; Energy resolution
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1610.03513

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.