Development of large-volume 130TeO2 bolometers for the CROSS 2ß decay search experiment

Avignone, F. T. ; Barabash, A. S. ; Berest, V. ; Bergé, L. ; Calvo-Mozota, J. M. ; Carniti, P. ; Chapellier, M. ; Dafinei, I. ; Danevich, F. A. ; Dumoulin, L. ; Ferella, F. ; Ferri, F. ; Gallas, A. ; Giuliani, A. ; Gotti, C. ; Gras, P. ; Ianni, A. ; Imbert, L. ; Khalife, H. ; Kobychev, V. V. ; Konovalov, S. I. ; Loaiza, P. ; de Marcillac, P. ; Marnieros, S. ; Marrache-Kikuchi, C. A. ; Martinez, M. (Universidad de Zaragoza) ; Nisi, S. ; Nones, C. ; Olivieri, E. ; Ortiz de Solórzano, A. (Universidad de Zaragoza) ; Peinaud, Y. ; Pessina, G. ; Poda, D. V. ; Rosier, Ph. ; Scarpaci, J. A. ; Tretyak, V. I. ; Umatov, V. I. ; Zarytskyy, M. M. ; Zolotarova, A.

Resumen: We report on the development of thermal detectors based on large-size tellurium dioxide crystals (45 × 45 × 45 mm), containing tellurium enriched in 130Te to about 91%, for the CROSS double-beta decay experiment. A powder used for the crystals growth was additionally purified by the directional solidification method, resulting in the reduction of the concentration of impurities by a factor 10, to a few ppm of the total concentration of residual elements (the main impurity is Fe). The purest part of the ingot (the first ∼ 200 mm, about 80% of the total length of the cylindrical part of the ingot) was determined by scanning segregation profiles of impurities and used for the 130TeO2 powder production with no evidence of re-contamination. The crystal growth was verified with precursors produced from a powder with natural Te isotopic composition, and two small-size (20 × 20 × 10 mm) samples were tested at a sea-level laboratory showing high bolometric and spectrometric performance together with acceptable 210Po content (below 10 mBq/kg). This growth method was then applied for the production of six large cubic 130TeO2 crystals and 4 of them were taken randomly to be characterized at the Canfranc underground laboratory, in the CROSS-dedicated low-background cryogenic facility. Two 130TeO2 samples were coated with a thin, Script O(100 nm), metal film in form of Al layer (on 4 sides) or AlPd grid (on a single side) to investigate the possibility to tag surface events by pulse-shape discrimination. Similarly to the small natural precursors, large-volume 130TeO2 bolometers show high performance and even better internal purity (210Po activity ∼ 1 mBq/kg, while activities of 228Th and 226Ra are below 0.01 mBq/kg), satisfying requirements for the CROSS and, potentially, next-generation experiments.

Idioma: Inglés

DOI: 10.1088/1748-0221/19/09/P09013

Año: 2024

Publicado en: Journal of Instrumentation 19, 09 (2024), P09013 [23 pp.]
ISSN: 1748-0221

Financiación: info:eu-repo/grantAgreement/EC/H2020/742345/EU/Cryogenic Rare-event Observatory with Surface Sensitivity/CROSS

Tipo y forma: Article (Published version)

Área (Departamento): Área Técnica. Lab. y Talleres (Dpto. Física Teórica)
Área (Departamento): Área Física Atóm.Molec.y Nucl. (Dpto. Física Teórica)