Eur. Phys. J. C (2015) 75: 591
https://doi.org/10.1140/epjc/s10052-015-3822-x

Regular Article - Experimental Physics

Double-beta decay investigation with highly pure enriched Se for the LUCIFER experiment

¹ Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
² Dipartimento di Fisica, Sapienza Università di Roma, 00185, Rome, Italy
³ INFN, Sezione di Roma, 00185, Rome, Italy
⁴ Dipartimento di Chimica, Università di Pavia, 27100, Pavia, Italy
⁵ INFN, Sezione di Pavia, 27100, Pavia, Italy
⁶ Physics Department, Princeton University, Princeton, NJ, 08544, USA
⁷ INFN, Laboratori Nazionali del Gran Sasso, 67100, Assergi (L’Aquila), Italy
⁸ Dipartimento di Fisica, Università di Milano-Bicocca, 20126, Milan, Italy
⁹ INFN, Sezione di Milano Bicocca, 20126, Milan, Italy
¹⁰ INFN, Sezione di Genova, 16146, Genoa, Italy
¹¹ Dipartimento di Fisica, Università di Genova, 16126, Genoa, Italy
¹² Centre de Spectrometrié de Masse, 91405, Orsay, France
¹³ Gran Sasso Science Institute, 67100, L’Aquila, Italy
¹⁴ CEA, Irfu, SPP Centre de Saclay, 91191, Gif-sur-Yvette, France

^* e-mail: luca.pattavina@lngs.infn.it

Received: 10 August 2015
Accepted: 1 December 2015
Published online: 13 December 2015

Abstract

The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3 % enriched Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of Th, U and U are respectively: 61, 110 and 74 Bq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of Se to 0, 2 and 2 excited states of Kr of 3.410, 1.310 and 1.010 y, respectively, with a 90 % C.L.