arXiv subjects

A. Cruciani

Publications and source records attributed to A. Cruciani.

At least 55 records · Page 3Linked to original sources

arXiv2021

Measurement of $^{216}$Po half-life with the CUPID-0 experiment

Rare event physics demands very detailed background control, high-performance detectors, and custom analysis strategies. Cryogenic calorimeters combine all these ingredients very effectively, representing a promising tool for next-generation experiments. CUPID-0 is one of the most advanced examples of such a technique, having demonstrated its potential with several results obtained with limited exposure. In this paper, we present a further application. Exploiting the analysis of delayed coincidence, we can identify the signals caused by the $^{220}$Rn-$^{216}$Po decay sequence on an event-by-event basis. The analysis of these events allows us to extract the time differences between the two decays, leading to a new evaluation of $^{216}$ half-life, estimated as (143.3 $\pm$ 2.8) ms.

nucl-ex↗

arXiv2021

Non-linearity in the system of quasiparticles of a superconducting resonator

We observed a strong non-linearity in the system of quasiparticles of a superconducting aluminum resonator, due to the Cooper-pair breaking from the absorbed readout power. We observed both negative and positive feedback effects, controlled by the detuning of the readout frequency, which are able to alter the relaxation time of quasiparticles by a factor greater than 10. We estimate that the (70+/-5) % of the total non-linearity of the device is due to quasiparticles.

cond-mat.supr-con↗

arXiv2020

Double beta decay results from the CUPID-0 experiment

A convincing observation of neutrino-less double beta decay (0$ν$DBD) relies on the possibility of operating high energy-resolution detectors in background-free conditions. Scintillating cryogenic calorimeters are one of the most promising tools to fulfill the requirements for a next-generation experiment. Several steps have been taken to demonstrate the maturity of this technique, starting from the successful experience of CUPID-0. The CUPID-0 experiment demonstrated the complete rejection of the dominant alpha background measuring the lowest counting rate in the region of interest for this technique. Furthermore, the most stringent limit on the $^{82}$Se 0$ν$DBD was established running 26 ZnSe crystals during two years of continuous detector operation. In this contribution we present the final results of CUPID-0 Phase I including a detailed model of the background, the measurement of the $^{82}$Se 2$ν$DBD half-life and the evidence that this nuclear transition is single state dominated.

nucl-ex↗

arXiv2020

Characterization of cubic Li$_{2}$$^{100}$MoO$_4$ crystals for the CUPID experiment

The CUPID Collaboration is designing a tonne-scale, background-free detector to search for double beta decay with sufficient sensitivity to fully explore the parameter space corresponding to the inverted neutrino mass hierarchy scenario. One of the CUPID demonstrators, CUPID-Mo, has proved the potential of enriched Li$_{2}$$^{100}$MoO$_4$ crystals as suitable detectors for neutrinoless double beta decay search. In this work, we characterised cubic crystals that, compared to the cylindrical crystals used by CUPID-Mo, are more appealing for the construction of tightly packed arrays. We measured an average energy resolution of (6.7$\pm$0.6) keV FWHM in the region of interest, approaching the CUPID target of 5 keV FWHM. We assessed the identification of $α$ particles with and without a reflecting foil that enhances the scintillation light collection efficiency, proving that the baseline design of CUPID already ensures a complete suppression of this $α$-induced background contribution. We also used the collected data to validate a Monte Carlo simulation modelling the light collection efficiency, which will enable further optimisations of the detector.

physics.ins-det↗

arXiv2020

A CUPID Li$_{2}$$^{100}$MoO$_4$ scintillating bolometer tested in the CROSS underground facility

A scintillating bolometer based on a large cubic Li$_{2}$$^{100}$MoO$_4$ crystal (45 mm side) and a Ge wafer (scintillation detector) has been operated in the CROSS cryogenic facility at the Canfranc underground laboratory in Spain. The dual-readout detector is a prototype of the technology that will be used in the next-generation $0\nu2β$ experiment CUPID. The measurements were performed at 18 and 12 mK temperature in a pulse tube dilution refrigerator. This setup utilizes the same technology as the CUORE cryostat that will host CUPID and so represents an accurate estimation of the expected performance. The Li$_{2}$$^{100}$MoO$_4$ bolometer shows a high energy resolution of 6 keV FWHM at the 2615 keV $γ$ line. The detection of scintillation light for each event triggered by the Li$_{2}$$^{100}$MoO$_4$ bolometer allowed for a full separation ($\sim$8$σ$) between $γ$($β$) and $α$ events above 2 MeV. The Li$_{2}$$^{100}$MoO$_4$ crystal also shows a high internal radiopurity with $^{228}$Th and $^{226}$Ra activities of less than 3 and 8 $μ$Bq/kg, respectively. Taking also into account the advantage of a more compact and massive detector array, which can be made of cubic-shaped crystals (compared to the cylindrical ones), this test demonstrates the great potential of cubic Li$_{2}$$^{100}$MoO$_4$ scintillating bolometers for high-sensitivity searches for the $^{100}$Mo $0\nu2β$ decay in CROSS and CUPID projects.

physics.ins-det↗

arXiv2020

Search for Neutrino-less Double Beta Decay of $^{64}$Zn and $^{70}$Zn with CUPID-0

CUPID-0 is the first pilot experiment of CUPID, a next-generation project searching for neutrino-less double beta decay. In its first scientific run, CUPID-0 operated 26 ZnSe cryogenic calorimeters coupled to light detectors in the underground Laboratori Nazionali del Gran Sasso. In this work, we analyzed a ZnSe exposure of 11.34 kg$\times$yr to search for the neutrino-less double beta decay of $^{70}$Zn and for the neutrino-less positron-emitting electron capture of $^{64}$Zn. We found no evidence for these decays and set 90$\%$ credible interval limits of ${\rm T}_{1/2}^{0νββ}(^{70}{\rm Zn}) > 1.6 \times 10^{21}$ yr and ${\rm T}_{1/2}^{0νEC β+}(^{64}{\rm Zn}) > 1.2 \times 10^{22}$ yr, surpassing by almost two orders of magnitude the previous experimental results

nucl-ex↗

arXiv2019

Evidence of Single State Dominance in the Two-Neutrino Double-$β$ Decay of Se-82 with CUPID-0

We report on the measurement of the two-neutrino double-$β$ decay of $^{82}$Se performed for the first time with cryogenic calorimeters, in the framework of the CUPID-0~experiment. With an exposure of 9.95 kg$\times$yr of Zn$^{82}$Se, we determine the two-neutrino double-$β$ decay half-life of $^{82}$Se with an unprecedented precision level, $T_{1/2}^{2ν} = [8.60 \pm 0.03 \textrm{(stat.)}~^{+0.17}_{-0.10} \textrm{(syst.)}] \times 10^{19}~\textrm{yr}$. The very high signal-to-background ratio, along with the detailed reconstruction of the background sources allowed us to identify the single state dominance as the underlying mechanism of such process, demonstrating that the higher state dominance hypothesis is disfavored at the level of 5.5 $σ$.

nucl-ex↗

arXiv2019

First search for Lorentz violation in double beta decay with scintillating calorimeters

We present the search for Lorentz violation in the double beta decay of ^{82}Se~with CUPID-0, using an exposure of 9.95 kg x y. We found no evidence for the searched signal and set a limit on the isotropic components of the Lorentz violating coefficient of $\mathring{a}_{\text{of}}^{(3)} < 4.1\cdot10^{-6}$ GeV (90\% Credible Interval). This results is obtained with a Bayesian analysis of the experimental data and fully includes the systematic uncertainties of the model. This is the first limit on $\mathring{a}_{\text{of}}^{(3)}$ obtained with a scintillating bolometer, showing the potentiality of this technique.

nucl-ex↗

arXiv2019

Phonon and light read out of a Li$_2$MoO$_4$ crystal with multiplexed kinetic inductance detectors

Molybdenum based crystals such as Li$_2$MoO$_4$ and CaMoO$_4$ are emerging as leading candidates for next generation experiments searching for neutrino-less double beta decay with cryogenic calorimeters (CUPID, AMoRE). The exquisite energy resolution and high radio-purity of these crystals come at the cost of a potentially detrimental background source: the two neutrinos double beta decay of $^{100}$Mo. Indeed, the fast half-life of this decay mode, combined with the slow response of cryogenic calorimeters, would result in pile-up events in the energy region of interest for neutrino-less double beta decay, reducing the experimental sensitivity. This background can be suppressed using fast and high sensitivity cryogenic light detectors, provided that the scintillation time constant itself does not limit the time resolution. We developed a new detection technique exploiting the high sensitivity, the fast time response and the multiplexing capability of Kinetic Inductance Detectors. We applied the proposed technique to a $2\times2\times2$ cm$^3$ Li$_2$MoO$_4$ crystal, which was chosen as baseline option for CUPID. We measured simultaneously both the phonon and scintillation signals with KIDs. We derived the scintillation time constant of this compound at millikelvin temperatures obtaining $τ_{scint} = 84.5\pm4.5\rm{(syst)}\pm1.0\rm{(stat)}$ $μ$s, constant between 10 and 190 mK.

physics.ins-det↗

arXiv2019

Background Model of the CUPID-0 Experiment

CUPID-0 is the first large mass array of enriched Zn$^{82}$Se scintillating low temperature calorimeters, operated at LNGS since 2017. During its first scientific runs, CUPID-0 collected an exposure of 9.95 kg yr. Thanks to the excellent rejection of $α$ particles, we attained the lowest background ever measured with thermal detectors in the energy region where we search for the signature of $^{82}$Se neutrinoless double beta decay. In this work we develop a model to reconstruct the CUPID-0 background over the whole energy range of experimental data. We identify the background sources exploiting their distinctive signatures and we assess their extremely low contribution (down to $\sim10^{-4}$ counts/(keV kg yr)) in the region of interest for $^{82}$Se neutrinoless double beta decay search. This result represents a crucial step towards the comprehension of the background in experiments based on scintillating calorimeters and in next generation projects such as CUPID.

nucl-ex↗

arXiv2019

Strong evidence of Anomalous Microwave Emission from the flux density spectrum of M31

We have observed the Andromeda galaxy, Messier 31 (M31), at 6.7GHz with the Sardinia Radio Telescope. We mapped the radio emission in the C-band, re-analyzed WMAP and Planck maps, as well as other ancillary data, and we have derived an overall integrated flux density spectrum from the radio to the infrared. This allowed us to estimate the emission budget from M31. Integrating over the whole galaxy, we found strong and highly significant evidence for anomalous microwave emission (AME), at the level of (1.45+0.17-0.19)Jy at the peaking frequency of ~25GHz. Decomposing the spectrum into known emission mechanisms such as free-free, synchrotron, thermal dust, and AME arising from electric dipole emission from rapidly rotating dust grains, we found that the overall emission from M31 is dominated, at frequencies below 10GHz, by synchrotron emission with a spectral index of -1.10+0.10-0.08, with subdominant free-free emission. At frequencies >10GHz, AME has a similar intensity to that of synchrotron and free-free emission, overtaking them between 20GHz and 50GHz, whereas thermal dust emission dominates the emission budget at frequencies above 60GHz, as expected.

astro-ph.GA↗

arXiv2019

Measurements and simulations of athermal phonon transmission from silicon absorbers to aluminium sensors

Phonon reflection and transmission at the interfaces plays a fundamental role in cryogenic particle detectors, in which the optimization of the phonon signal at the sensor (in case of phonon-mediated detectors) or the minimization of the heat transmission (when the detection occurs in the sensor itself) is of primary importance to improve sensitivity. Nevertheless, the mechanisms governing the phonon physics at the interfaces are still not completely understood. The two more successful models, the acoustic mismatch model (AMM) and diffuse mismatch model (DMM) are not able to explain all the accumulated experimental data and the measurement of the transmission coefficients between the materials remains a challenge. Here, we use measurements of the athermal phonon flux in aluminium Kinetic Inductance Detectors (KID) deposited on silicon substrates following a particle interaction to validate a Monte Carlo (MC) phonon simulation. We apply the Mattis-Bardeen theory to derive the phonon pulse energy and timing from the KID signal and compare the results with the MC for both AMM and DMM models, finding a remarkable good agreement for AMM, while diffuse reflection is clearly disfavored. For an aluminum film of 60 nm and a silicon substrate of 380~$μ$m, we obtain transmission coefficients Si-Al in the range [0.3-0.55] and Si-Teflon in the range [0.1-0.15].

physics.ins-det↗

arXiv2019

Final result of CUPID-0 phase-I in the search for the $^{82}$Se Neutrinoless Double Beta Decay

CUPID-0 is the first pilot experiment of CUPID, a next-generation project for the measurement of neutrinoless double beta decay (0$ν$DBD) with scintillating bolometers. The detector, consisting of 24 enriched and 2 natural ZnSe crystals, has been taking data at Laboratori Nazionali del Gran Sasso from June 2017 to December 2018, collecting a $^{82}$Se exposure of 5.29 kg$\times$yr. In this paper we present the phase-I results in the search for 0$ν$DBD. We demonstrate that the technology implemented by CUPID-0 allows us to reach the lowest background for calorimetric experiments: $(3.5^{+1.0}_{-0.9})\times10^{-3}$ counts/(keV kg yr). Monitoring 3.88$\times$10$^{25}$ $^{82}$Se nuclei$\times$yr we reach a 90% credible interval median sensitivity of $\rm{T}^{0ν}_{1/2}>5.0\times10^{24} \rm{yr}$ and set the most stringent limit on the half-life of $^{82}$Se 0$ν$DBD : $\rm{T}^{0ν}_{1/2}>3.5\times10^{24} \rm{yr}$ (90% credible interval), corresponding to m$_{ββ} <$ (311-638) meV depending on the nuclear matrix element calculations.

nucl-ex↗

arXiv2018

Search of the neutrino-less double beta decay of $^{82}$Se into the excited states of $^{82}$Kr with CUPID-0

The CUPID0 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 $^{82}$Se and 2 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 $^{82}$Se into the 0$_1^+$, 2$_1^+$ and 2$_2^+$ excited states of $^{82}$Kr with an exposure of 5.74 kg$\cdot$yr (2.24$\times$10$^{25}$ emitters$\cdot$yr). We found no evidence of the decays and set the most stringent limits on the widths of these processes: $Γ$($^{82}$Se $\rightarrow ^{82}$Kr$_{0_1^+}$)$<$8.55$\times$10$^{-24}$ yr$^{-1}$, $Γ$($^{82}$Se $\rightarrow ^{82}$Kr$_{2_1^+}$)$<6.25 \times10^{-24}$ yr$^{-1}$, $Γ$($^{82}$Se $\rightarrow ^{82}$Kr$_{2_2^+}$)$<$8.25$\times$10$^{-24}$ yr$^{-1}$ (90$\%$ credible interval

nucl-ex↗

arXiv2018

Analysis of cryogenic calorimeters with light and heat read-out for double beta decay searches

The suppression of spurious events in the region of interest for neutrinoless double beta decay will play a major role in next generation experiments. The background of detectors based on the technology of cryogenic calorimeters is expected to be dominated by α particles, that could be disentangled from double beta decay signals by exploiting the difference in the emission of the scintillation light. CUPID-0, an array of enriched Zn$^{82}$Se scintillating calorimeters, is the first large mass demonstrator of this technology. The detector started data-taking in 2017 at the Laboratori Nazionali del Gran Sasso with the aim of proving that dual read-out of light and heat allows for an efficient suppression of the α background. In this paper we describe the software tools we developed for the analysis of scintillating calorimeters and we demonstrate that this technology allows to reach an unprecedented background for cryogenic calorimeters.

physics.ins-det↗

arXiv2018

First Result on the Neutrinoless Double Beta Decay of $^{82}$Se with CUPID-0

We report the result of the search for neutrinoless double beta decay of $^{82}$Se obtained with CUPID-0, the first large array of scintillating Zn$^{82}$Se cryogenic calorimeters implementing particle identification. We observe no signal in a 1.83 kg yr $^{82}$Se exposure and we set the most stringent lower limit on the \onu $^{82}$Se half-life T$^{0ν}_{1/2}>$ 2.4$\times \mathrm{10}^{24}$ yr (90\% credible interval), which corresponds to an effective Majorana neutrino mass m$_{ββ} <$ (376-770) meV depending on the nuclear matrix element calculations. The heat-light readout provides a powerful tool for the rejection of \al\ particles and allows to suppress the background in the region of interest down to (3.6$^{+1.9}_{-1.4}$)$\times$10$^{-3}$\ckky, an unprecedented level for this technique.

nucl-ex↗

arXiv2018

Al/Ti/Al phonon-mediated KIDs for UV-VIS light detection over large areas

The development of wide-area cryogenic light detectors with baseline energy resolution lower than 20 eV RMS is essential for next generation bolometric experiments searching for rare interactions. Indeed the simultaneous readout of the light and heat signals will enable background suppression through particle identification. Because of their excellent intrinsic energy resolution, as well as their well-established reproducibility, Kinetic Inductance Detectors (KIDs) are good candidates for the development of next generation light detectors. The CALDER project is investigating the potential of phonon-mediated KIDs. The first phase of the project allowed to reach a baseline resolution of 80 eV using a single KID made of aluminium on a 2x2 cm\tmrsup{$2$} silicon substrate acting as photon absorber. In this paper we present a new prototype detector implementing a trilayer aluminium-titanium-aluminium KID. Taking advantage of the superconducting proximity effect the baseline resolution improves down to 26 eV.

physics.ins-det↗

arXiv2018

CUPID-0: the first array of enriched scintillating bolometers for 0νββdecay investigations

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$νββ$). CUPID-0 aims at measuring a background index in the region of interest (RoI) for 0$νββ$ at the level of 10$^{-3}$ c/keV/kg/y, the lowest value ever measured using cryogenic detectors. This result can be achieved by a state of the art technology for background suppression and thorough protocols and procedures for 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 detector performance which are here preliminarily discussed

physics.ins-det↗