Development of large-volume $^{130}$TeO$_2$ bolometers for the CROSS $2\beta$ decay search experiment
Abstract
We report on the development of thermal detectors based on large-size tellurium dioxide crystals (45x45x45 mm), containing tellurium enriched in Te 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 TeO powder production with no evidence of re-contamination. The crystal growth was verified with precursors produced from powder with natural Te isotopic composition, and two small-size (20x20x10 mm) samples were tested at a sea-level laboratory showing high bolometric and spectrometric performance together with acceptable Po content (below 10 mBq/kg). This growth method was then applied for the production of six large cubic TeO 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 TeO samples were coated with a thin, (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 TeO bolometers show high performance and even better internal purity (Po activity 1 mBq/kg, while activities of Th and Ra are below 0.01 mBq/kg), satisfying requirements for the CROSS and, potentially, next-generation experiments.
Keywords
Cite
@article{arxiv.2406.01444,
title = {Development of large-volume $^{130}$TeO$_2$ bolometers for the CROSS $2\beta$ decay search experiment},
author = {F. T. Avignone and A. S. Barabash and V. Berest and L. Bergé and J. M. Calvo-Mozota and P. Carniti and M. Chapellier and I. Dafinei and F. A. Danevich and L. Dumoulin and F. Ferella and F. Ferri and A. Gallas and A. Giuliani and C. Gotti and P. Gras and A. Ianni and L. Imbert and H. Khalife and V. V. Kobychev and S. I. Konovalov and P. Loaiza and P. de Marcillac and S. Marnieros and C. A. Marrache-Kikuchi and M. Martinez and S. Nisi and C. Nones and E. Olivieri and A. Ortiz de Solórzano and Y. Peinaud and G. Pessina and D. V. Poda and Ph. Rosier and J. A. Scarpaci and V. I. Tretyak and V. I. Umatov and M. M. Zarytskyy and A. Zolotarova},
journal= {arXiv preprint arXiv:2406.01444},
year = {2024}
}
Comments
Submitted to JINST; 22 pages, 11 figures, 4 tables