MARE, Microcalorimeter Arrays for a Rhenium Experiment: A detector overview

Abstract We describe and discuss the features of MARE, an experiment based on arrays of rhenium low temperature microcalorimeters that have the potential to bring the sensitivity to the neutrino mass down to 0.2 eV, by studying the beta spectrum of Re 187 ( Q -value = 2.47 keV)

The commissioning of the CUORE experiment: the mini-tower run

CUORE is a ton-scale experiment approaching the data taking phase in Gran Sasso National Laboratory. Its primary goal is to search for the neutrinoless double-beta decay in 130Te using 988 crystals of tellurim dioxide. The crystals are operated as bolometers at about 10 mK taking advantage of one of the largest dilution cryostat ever built. Concluded in March 2016, the cryostat commissioning consisted in a sequence of cool down runs each one integrating new parts of the apparatus. The last run was performed with the fully configured cryostat and the thermal load at 4 K reached the impressive mass of about 14 tons. During that run the base temperature of 6.3 mK was reached and maintained for more than 70 days. An array of 8 crystals, called mini-tower, was used to check bolometers operation, readout electronics and DAQ. Results will be presented in terms of cooling power, electronic noise, energy resolution and preliminary background measurements

Results from the Cuore Experiment

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers, each of them made of 52 crystals. The construction of the experiment was completed in August 2016 and the data taking started in spring 2017 after a period of commissioning and tests. In this work we present the neutrinoless double beta decay results of CUORE from examining a total TeO2 exposure of 86.3kg yr, characterized by an effective energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts/ (keV kg yr). In this physics run, CUORE placed a lower limit on the decay half- life of neutrinoless double beta decay of 130Te > 1.3.1025 yr (90% C. L.). Moreover, an analysis of the background of the experiment is presented as well as the measurement of the 130Te 2vo3p decay with a resulting half- life of T2 2. [7.9 :- 0.1 (stat.) :- 0.2 (syst.)] x 10(20) yr which is the most precise measurement of the half- life and compatible with previous results

Composite macro-bolometers for the rejection of surface radioactive background in rare-event experiments

International audienceExperiments searching for rare events, such as neutrinoless double beta decay and interactions of dark matter candidates, require extremely low levels of background. When these experiments are performed using macro-bolometers, radioactive contamination near the surfaces is of particular concern. For a bolometric neutrinoless double beta decay experiment, it can cause counts in the spectral region where the signal is expected, while for a dark matter experiment which exploits ionization signals for particle identification, it originates an incomplete charge collection simulating a nuclear recoil. In order to control the effects of surface contamination, we developed a novel technique that uses composite macro-bolometers to identify energy depositions that occur close to the surfaces of materials immediately surrounding the detector. The composite macro-bolometer proposed and studied here consists of a main energy absorber that is thermally coupled to and entirely surrounded by thin absorbers that act as active shields. Surface energy depositions can be rejected by the analysis of simultaneous signals in the main absorber and the shields. In this paper, we describe a full thermal model and experimental results for three prototype detectors. The detectors consist of Ge, Si, or TeO thin absorbers as active shields, all with TeO crystals as main absorbers. In all cases, the surface event rejection capability is clearly demonstrated. In addition, simulations and preliminary results show that it is possible to detect energy depositions that occurred on the shields without separate readout channels for them. The energy depositions in the shields are distinguished from those in the main absorber through pulse shape discrimination. This simplification makes this technique a viable method for the rejection of surface energy depositions in next-generation bolometric double beta decay searches, such as possible extensions or upgrades of the CUORE experiment

MARE, Microcalorimeter Arrays for a Rhenium Experiment: A detector overview

We describe and discuss the features of MARE, an experiment based on arrays of rhenium low temperature microcalorimeters that have the potential to bring the sensitivity to the neutrino mass down to 0.2eV, by studying the \u3b2 spectrum of Re187 (Q-value = 2.47keV)

Results from CUORICINO and prospects for CUORE.

CUORE will be an observatory for rare events consisting of a tightly packed array of TeO2 bolometers, with a total mass of similar to 740 kg, operating in the underground Gran Sasso laboratory. A first step towards CUORE is CUORICINO, a running experiment with 40.7 kg of TeO2. Present results from CUORICINO for the neutrinoless double beta decay of Te-130 will be presented here (T-1/2(0 nu) >= 1.0x10(24) y, <= 0.26-1.4 eV at 90% C.L.). The status of CUORE preparation and its physics potential, including dark matter searches, will be shown

CUORE: first results and prospects

International audienceCUORE is the first bolometric tonne-scale experiment aiming at the investigation of neutrinoless double-beta (0$\nu$2$\beta$) decay of $^{130}$Te. The cryogenic commissioning followed by the detector installation and cool down took place during 2016. After the optimisation of all the detectors, the data-taking started in spring 2017. We report about the results of the first dataset acquired in May, which led to a limit on the 0$\nu$2$\beta$ half-life of $^{130}$Te of 6.6$\times$10$^{24}$ yr. An upgrade of CUORE, named CUPID, is planned to improve the 0$\nu$2$\beta$-decay sensitivity via passive and active background reduction and crystal enrichment. Some technologies for CUPID are currently under study and two of them are presented here, involving the detection of Cherenkov and scintillation light emitted by enriched $^{130}$TeO$_2$ and Li$^{100}_2$MoO$_4$ crystals respectively. This will allow us to reject the currently dominant a background