Search

The CUPID-0 experiment searches for double beta decay using cryogenic calorimeters with double (heat and light) read-out. The detector, consisting of 24 ZnSe crystals 95$$\%$$ % enriched in $$^{82}$$ 82 Se and two natural ZnSe crystals, started data-taking in 2017 at Laboratori Nazionali del Gran Sasso. We present the search for the neutrino-less double beta decay of $$^{82}$$ 82 Se into the 0$$_1^+$$ 1+ , 2$$_1^+$$ 1+ and 2$$_2^+$$ 2+ excited states of $$^{82}$$ 82 Kr with an exposure of 5.74 kg$$\cdot $$ · yr (2.24$$\times $$ × 10$$^{25}$$ 25 emitters$$\cdot $$ · yr). We found no evidence of the decays and set the most stringent limits on the widths of these processes: $$\varGamma $$ Γ ($$^{82}$$ 82 Se $$\rightarrow ^{82}$$ →82 Kr$$_{0_1^+}$$ 01+ )8.55$$\times $$ × 10$$^{-24}$$ -24 yr$$^{-1}$$ -1 , $$\varGamma $$ Γ ($$^{82}$$ 82 Se $$\rightarrow ^{82}$$ →82 Kr $$_{2_1^+}$$ 21+ )$$\,{<6.25×10-24 yr$$^{-1}$$ -1 , $$\varGamma $$ Γ ($$^{82}$$ 82 Se $$\rightarrow ^{82}$$ →82 Kr$$_{2_2^+}$$ 22+ )8.25$$\times $$ × 10$$^{-24}$$ -24 yr$$^{-1}$$ -1 (90$$\%$$ % credible interval).

The CUPID-0 detector hosted at the Laboratori Nazionali del Gran Sasso, Italy, is the first large array of enriched scintillating cryogenic detectors for the investigation of $$^{82}$$ 82 Se neutrinoless double-beta decay ($$0\nu \beta \beta $$ 0νββ ). CUPID-0 aims at measuring a background index in the region of interest (RoI) for $$0\nu \beta \beta $$ 0νββ at the level of 10$$^{-3}$$ -3 counts/(keV kg years), the lowest value ever measured using cryogenic detectors. CUPID-0 operates an array of Zn$$^{82}$$ 82 Se scintillating bolometers coupled with bolometric light detectors, with a state of the art technology for background suppression and thorough protocols and procedures for the detector preparation and construction. In this paper, the different phases of the detector design and construction will be presented, from the material selection (for the absorber production) to the new and innovative detector structure. The successful construction of the detector lead to promising preliminary detector performance which is discussed here.

CUPID-Mo is a bolometric experimental demonstrator searching for neutrinoless double beta (0ν2β) decay of 100Mo. The observation of this process, which is not allowed by the Standard Model, would determine the Majorana nature of neutrino and its mass scale. The CUPID-Mo detector array consists of 20 scintillating bolometers made of Li2100MoO4 crystals (2.34 kg of 100Mo), assembled in a compact structure of 5 suspended towers. Data taking will start soon in the EDELWEISS cryostat at the Underground Laboratory of Modane (LSM, France). The main goal of the CUPID-Mo experiment is to demonstrate “zero-background” conditions in the region of the expected 0ν2β decay signal of 100Mo over six months of measurement. The reproducibility of Li2100MoO4 scintillating bolometers with high performance should be confirmed, demonstrating the applicability of the CUPID-Mo technology for the future ton-scale 0ν2β decay bolometric experiment CUPID.

International audience; The CUPID-0 detector hosted at the Laboratori Nazionali del Gran Sasso, Italy, is the first large array of enriched scintillating cryogenic detectors for the investigation of$^{82}$ Se neutrinoless double-beta decay ( $0\nu \beta \beta $ ). CUPID-0 aims at measuring a background index in the region of interest (RoI) for $0\nu \beta \beta $ at the level of 10$^{-3}$ counts/(keV kg years), the lowest value ever measured using cryogenic detectors. CUPID-0 operates an array of Zn$^{82}$ Se scintillating bolometers coupled with bolometric light detectors, with a state of the art technology for background suppression and thorough protocols and procedures for the detector preparation and construction. In this paper, the different phases of the detector design and construction will be presented, from the material selection (for the absorber production) to the new and innovative detector structure. The successful construction of the detector lead to promising preliminary detector performance which is discussed here.

This paper reports on the development of a technology involving \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{100}\hbox {Mo}$$\end{document}100Mo-enriched scintillating bolometers, compatible with the goals of CUPID, a proposed next-generation bolometric experiment to search for neutrinoless double-beta decay. Large mass (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim 1~\hbox {kg}$$\end{document}∼1kg), high optical quality, radiopure \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{100}\hbox {Mo}$$\end{document}100Mo-containing zinc and lithium molybdate crystals have been produced and used to develop high performance single detector modules based on 0.2–0.4 kg scintillating bolometers. In particular, the energy resolution of the lithium molybdate detectors near the Q-value of the double-beta transition of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{100}\hbox {Mo}$$\end{document}100Mo (3034 keV) is 4–6 keV FWHM. The rejection of the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha $$\end{document}α-induced dominant background above 2.6 MeV is better than \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$8\sigma $$\end{document}8σ. Less than \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$10~\upmu \hbox {Bq/kg}$$\end{document}10μBq/kg activity of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{232}\hbox {Th}\, (^{228}\hbox {Th})$$\end{document}232Th(228Th) and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{226}\hbox {Ra}$$\end{document}226Ra in the crystals is ensured by boule recrystallization. The potential of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{100}\hbox {Mo}$$\end{document}100Mo-enriched scintillating bolometers to perform high sensitivity double-beta decay searches has been demonstrated with only \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$10~\hbox {kg}\times \hbox {d}$$\end{document}10kg×d exposure: the two neutrino double-beta decay half-life of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{100}\hbox {Mo}$$\end{document}100Mo has been measured with the up-to-date highest accuracy as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_{1/2}$$\end{document}T1/2 = [6.90 ± 0.15(stat.) ± 0.37(syst.)] \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times ~10^{18}~\hbox {years}$$\end{document}×1018years. Both crystallization and detector technologies favor lithium molybdate, which has been selected for the ongoing construction of the CUPID-0/Mo demonstrator, containing several kg of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{100}\hbox {Mo}$$\end{document}100Mo.

International audience; CUPID-0 is an array of 24 Zn82Se scintillating bolometers used to search for the 0νββ decay of 82Se. It is the first large mass 0νββ experiment exploiting a double read-out technique: the phonon signal to accurately measure particle energies and the light signal to reject the α-induced background. Its success might open the road to a next generation project of ton mass scale, CUPID. The array is in operation at Laboratori Nazionali del Gran Sasso since the beginning of 2017, in this paper we present the preliminary results obtained with an exposure of 10.45 kg· y.

© 2016, The Author(s). The R&D activity performed during the last years proved the potential of ZnSe scintillating bolometers to the search for neutrino-less double beta decay, motivating the realization of the first large-mass experiment based on this technology: CUPID-0. The isotopic enrichment in82Se, the Zn82Se crystals growth, as well as the light detectors production have been accomplished, and the experiment is now in construction at Laboratori Nazionali del Gran Sasso (Italy). In this paper we present the results obtained testing the first three Zn82Se crystals operated as scintillating bolometers, and we prove that their performance in terms of energy resolution, background rejection capability and intrinsic radio-purity complies with the requirements of CUPID-0.

The R&D activity performed during the last years proved the potential of ZnSe scintillating bolometers to the search for neutrino-less double beta decay, motivating the realization of the first large-mass experiment based on this technology: CUPID-0. The isotopic enrichment in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{82}$$\end{document}82Se, the Zn\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{82}$$\end{document}82Se crystals growth, as well as the light detectors production have been accomplished, and the experiment is now in construction at Laboratori Nazionali del Gran Sasso (Italy). In this paper we present the results obtained testing the first three Zn\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{82}$$\end{document}82Se crystals operated as scintillating bolometers, and we prove that their performance in terms of energy resolution, background rejection capability and intrinsic radio-purity complies with the requirements of CUPID-0.

The CRESST-II experiment uses cryogenic detectors to search for nuclear recoil events induced by the elastic scattering of dark matter particles in CaWO$_4$ crystals. Given the low energy threshold of our detectors in combination with light target nuclei, low mass dark matter particles can be probed with high sensitivity. In this letter we present the results from data of a single detector module corresponding to 52 kg live days. A blind analysis is carried out. With an energy threshold for nuclear recoils of 307 eV we substantially enhance the sensitivity for light dark matter. Thereby, we extend the reach of direct dark matter experiments to the sub-region and demonstrate that the energy threshold is the key parameter in the search for low mass dark matter particles., 8 pages, 8 figures

The R&D activity performed during the last years proved the potential of ZnSe scintillating bolometers to the search for neutrino-less double beta decay, motivating the realization of the first large-mass experiment based on this technology: CUPID-0. The isotopic enrichment in [Formula: see text]Se, the Zn[Formula: see text]Se crystals growth, as well as the light detectors production have been accomplished, and the experiment is now in construction at Laboratori Nazionali del Gran Sasso (Italy). In this paper we present the results obtained testing the first three Zn[Formula: see text]Se crystals operated as scintillating bolometers, and we prove that their performance in terms of energy resolution, background rejection capability and intrinsic radio-purity complies with the requirements of CUPID-0.

The R&D; activity performed during the last years proved the potential of ZnSe scintillating bolometers to the search for neutrino-less double beta decay, motivating the realization of the first large-mass experiment based on this technology: CUPID-0. The isotopic enrichment in 82 Se, the Zn 82 Se crystals growth, as well as the light detectors production have been accomplished, and the experiment is now in construction at Laboratori Nazionali del Gran Sasso (Italy). In this paper we present the results obtained testing the first three Zn 82 Se crystals operated as scintillating bolometers, and we prove that their performance in terms of energy resolution, background rejection capability and intrinsic radio-purity complies with the requirements of CUPID-0.

The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of 82 Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched 82 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 82 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 232 Th, 238 U and 235 U are respectively: < 61, < 110 and < 74 μ Bq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the 82 Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of 82 Se to 0 1+ , 2 2+ and 2 1+ excited states of 82 Kr of 3.4 · 10 22 , 1.3 · 10 22 and 1.0 · 10 22  y, respectively, with a 90 % C.L.

CUORE, an array of 988 TeO[Formula: see text] bolometers, is about to be one of the most sensitive experiments searching for neutrinoless double-beta decay. Its sensitivity could be further improved by removing the background from [Formula: see text] radioactivity. A few years ago it was pointed out that the signal from [Formula: see text]s can be tagged by detecting the emitted Cherenkov light, which is not produced by [Formula: see text]s. In this paper we confirm this possibility. For the first time we measured the Cherenkov light emitted by a CUORE crystal, and found it to be 100eV at the [Formula: see text]-value of the decay. To completely reject the [Formula: see text] background, we compute that one needs light detectors with baseline noise below 20eVRMS, a value which is 3-4 times smaller than the average noise of the bolometric light detectors we are using. We point out that an improved light detector technology must be developed to obtain TeO[Formula: see text] bolometric experiments able to probe the inverted hierarchy of neutrino masses.

© 2014, The Author(s). CUORE, an array of 988 TeO2 bolometers, is about to be one of the most sensitive experiments searching for neutrinoless double-beta decay. Its sensitivity could be further improved by removing the background from α radioactivity. A few years ago it was pointed out that the signal from $$\beta $$βs can be tagged by detecting the emitted Cherenkov light, which is not produced by αs. In this paper we confirm this possibility. For the first time we measured the Cherenkov light emitted by a CUORE crystal, and found it to be 100 eV at the Q-value of the decay. To completely reject the α background, we compute that one needs light detectors with baseline noise below 20 eV RMS, a value which is 3–4 times smaller than the average noise of the bolometric light detectors we are using. We point out that an improved light detector technology must be developed to obtain TeO2 bolometric experiments able to probe the inverted hierarchy of neutrino masses.

The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{82}$$\end{document}82Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{82}$$\end{document}82Se 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 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{82}$$\end{document}82Se 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 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{232}$$\end{document}232Th, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{238}$$\end{document}238U and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{235}$$\end{document}235U are respectively: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$

In the past years the spotlight of the search for dark matter particles widened to the low mass region, both from theoretical and experimental side. We discuss results from data obtained in 2013 with a single detector TUM40. This detector is equipped with a new upgraded holding scheme to efficiently veto backgrounds induced by surface alpha decays. This veto, the low threshold of 0.6keV and an unprecedented background level for CaWO$_4$ target crystals render TUM40 the detector with the best overall performance of CRESST-II phase 2 (July 2013 - August 2015). A low-threshold analysis allowed to investigate light dark matter particles (, Talk presented CIPANP2015, 6 pages, 6 figures