arXiv subjects

D. V. Poda

Publications and source records attributed to D. V. Poda.

At least 37 records · Page 2Linked to original sources

arXiv2023

Study of collision and $γ$-cascade times following neutron-capture processes in cryogenic detectors

The emission of $γ$-rays after a neutron capture in a cryogenic detector can generate mono-energetic nuclear recoils in the sub-keV regime, of direct interest for the calibration of Dark Matter and Coherent Elastic Neutrino Nucleus Scattering experiments. Here we show that accurate predictions of the nuclear recoil spectra induced by neutron captures require taking into account the interplay between the development in time of the de-excitation $γ$-cascade of the target nucleus and that of the associated atomic collisions in matter. We present detailed simulations coupling the FIFRELIN code for the description of the $γ$-cascades and the IRADINA code for the modelling of the fast atomic movements in matter. Nuclear recoil spectra are predicted, and made available to the community, for concrete cases of Al$_2$O$_3$, Si, Ge and CaWO$_4$ crystals exposed to a low intensity beam of thermal neutrons. We find that timing effects cause new calibration peaks to emerge in the recoil spectra and also impact the shape of the continuous recoil distribution. We discuss how they could give access to a rich physics program, spanning the accurate study of the response of cryogenic detectors in the sub-keV range, tests of solid state physics simulations and tests of nuclear models.

physics.ins-det↗

arXiv2023

The background model of the CUPID-Mo $0νββ$ experiment

CUPID-Mo, located in the Laboratoire Souterrain de Modane (France), was a demonstrator for the next generation $0νββ$ decay experiment, CUPID. It consisted of an array of 20 enriched Li$_{2}$$ ^{100}$MoO$_4$ bolometers and 20 Ge light detectors and has demonstrated that the technology of scintillating bolometers with particle identification capabilities is mature. Furthermore, CUPID-Mo can inform and validate the background prediction for CUPID. In this paper, we present a detailed model of the CUPID-Mo backgrounds. This model is able to describe well the features of the experimental data and enables studies of the $2νββ$ decay and other processes with high precision. We also measure the radio-purity of the Li$_{2}$$^{100}$MoO$_4$ crystals which are found to be sufficient for the CUPID goals. Finally, we also obtain a background index in the region of interest of 3.7$^{+0.9}_{-0.8}$(stat)$^{+1.5}_{-0.7}$(syst)$\times10^{-3}$counts/$Δ$E$_{FWHM}$/mol$_{iso}$/yr, the lowest in a bolometric $0νββ$ decay experiment.

hep-ex↗

arXiv2023

Li$_2$$^{100\textrm{depl}}$MoO$_4$ Scintillating Bolometers for Rare-Event Search Experiments

We report on the development of scintillating bolometers based on lithium molybdate crystals containing molybdenum depleted in the double-$β$ active isotope $^{100}$Mo (Li$_2$$^{100\textrm{depl}}$MoO$_4$). We used two Li$_2$$^{100\textrm{depl}}$MoO$_4$ cubic samples, 45 mm side and 0.28 kg each, produced following purification and crystallization protocols developed for double-$β$ search experiments with $^{100}$Mo-enriched Li$_2$MoO$_4$ crystals. Bolometric Ge detectors were utilized to register scintillation photons emitted by the Li$_2$$^{100\textrm{depl}}$MoO$_4$ crystal scintillators. The measurements were performed in the CROSS cryogenic set-up at the Canfranc underground laboratory (Spain). We observed that the Li$_2$$^{100\textrm{depl}}$MoO$_4$ scintillating bolometers are characterized by excellent spectrometric performance ($\sim$3--6 keV FWHM at 0.24--2.6 MeV $γ$'s), moderate scintillation signal ($\sim$0.3--0.6 keV/MeV depending on light collection conditions) and high radiopurity ($^{228}$Th and $^{226}$Ra activities are below a few $μ$Bq/kg), comparable to the best reported results of low-temperature detectors based on Li$_2$MoO$_4$ with natural or $^{100}$Mo-enriched molybdenum content. Prospects of Li$_2$$^{100\textrm{depl}}$MoO$_4$ bolometers for use in rare-event search experiments are briefly discussed.

physics.ins-det↗

arXiv2023

ZnO-based scintillating bolometers: New prospects to study double beta decay of $^{64}$Zn

The first detailed study on the performance of a ZnO-based cryogenic scintillating bolometer as a detector to search for rare processes in zinc isotopes was performed. A 7.2 g ZnO low-temperature detector, containing more than 80\% of zinc in its mass, exhibits good energy resolution of baseline noise 1.0--2.7 keV FWHM at various working temperatures resulting in a low-energy threshold for the experiment, 2.0--6.0 keV. The light yield for $β$/$γ$ events was measured as 1.5(3) keV/MeV, while it varies for $α$ particles in the range of 0.2--3.0 keV/MeV. The detector demonstrate an effective identification of the $β$/$γ$ events from $α$ events using time-properties of only heat signals. %(namely, Rise time parameter). The radiopurity of the ZnO crystal was evaluated using the Inductively Coupled Plasma Mass Spectrometry, an ultra-low-background High Purity Ge $γ$-spectrometer, and bolometric measurements. Only limits were set at the level of $\mathcal{O}$(1--100) mBq/kg on activities of \Nuc{K}{40}, \Nuc{Cs}{137} and daughter nuclides from the U/Th natural decay chains. The total internal $α$-activity was calculated to be 22(2) mBq/kg, with a major contribution caused by 6(1) mBq/kg of \Nuc{Th}{232} and 12(2) mBq/kg of \Nuc{U}{234}. Limits on double beta decay (DBD) processes in \Nuc{Zn}{64} and \Nuc{Zn}{70} isotopes were set on the level of $\mathcal{O}(10^{17}$--$10^{18})$ yr for various decay modes profiting from 271 h of acquired background data in the above-ground lab. This study shows a good potential for ZnO-based scintillating bolometers to search for DBD processes of Zn isotopes, especially in \Nuc{Zn}{64}, with the most prominent spectral features at $\sim$10--20 keV, like the two neutrino double electron capture. A 10 kg-scale experiment can reach the experimental sensitivity at the level of $\mathcal{O}(10^{24})$ yr.

physics.ins-det↗

arXiv2023

Enhanced light signal for the suppression of pile-up events in Mo-based bolometers for the $0νββ$ decay search

Random coincidences of events could be one of the main sources of background in the search for neutrino-less double-beta decay of $^{100}$Mo with macro-bolometers, due to their modest time resolution. Scintillating bolometers as those based on Li$_2$MoO$_4$ crystals and employed in the CROSS and CUPID experiments can eventually exploit the coincident fast signal detected in a light detector to reduce this background. However, the scintillation provides a modest signal-to-noise ratio, making difficult a pile-up pulse-shape recognition and rejection at timescales shorter than a few ms. Neganov-Trofimov-Luke assisted light detectors (NTL-LDs) offer the possibility to effectively increase the signal-to-noise ratio, preserving a fast time-response, and enhance the capability of pile-up rejection via pulse shape analysis. In this article we present: a) an experimental work performed with a Li$_2$MoO$_4$ scintillating bolometer, studied in the framework of the CROSS experiment, and utilizing a NTL-LD; b) a simulation method to reproduce, synthetically, randomly coincident two-neutrino double-beta decay events; c) a new analysis method based on a pulse-shape discrimination algorithm capable of providing high pile-up rejection efficiencies. We finally show how the NTL-LDs offer a balanced solution between performance and complexity to reach background index $\sim$$10^{-4}$ counts/keV/kg/year with 280~g Li$_2$MoO$_4$ ($^{100}$Mo enriched) bolometers at 3034 keV, the Q-value of the double-beta decay, and target the goal of a next generation experiment like CUPID.

physics.ins-det↗

arXiv2022

Final results on the $0νββ$ decay half-life limit of $^{100}$Mo from the CUPID-Mo experiment

The CUPID-Mo experiment to search for 0$νββ$ decay in $^{100}$Mo has been recently completed after about 1.5 years of operation at Laboratoire Souterrain de Modane (France). It served as a demonstrator for CUPID, a next generation 0$νββ$ decay experiment. CUPID-Mo was comprised of 20 enriched Li$_2$$^{100}$MoO$_4$ scintillating calorimeters, each with a mass of $\sim$ 0.2 kg, operated at $\sim$20 mK. We present here the final analysis with the full exposure of CUPID-Mo ($^{100}$Mo exposure of 1.47 kg$\times$yr) used to search for lepton number violation via 0$νββ$ decay. We report on various analysis improvements since the previous result on a subset of data, reprocessing all data with these new techniques. We observe zero events in the region of interest and set a new limit on the $^{100}$Mo 0$νββ$ decay half-life of $T^{0ν}_{1/2} > 1.8 \times 10^{24}$ year (stat.+syst.) at 90% CI. Under the light Majorana neutrino exchange mechanism this corresponds to an effective Majorana neutrino mass of $\left < (0.28$--$0.49)$ eV, dependent upon the nuclear matrix element utilized.

nucl-ex↗

arXiv2022

New measurement of double beta decays of $^{100}$Mo to excited states of $^{100}$Ru with the CUPID-Mo experiment

The CUPID-Mo experiment, located at Laboratoire Souterrain de Modane (France), was a demonstrator experiment for CUPID. It consisted of an array of 20 Li$_2^{100}$MoO$_4$ (LMO) calorimeters each equipped with a Ge light detector (LD) for particle identification. In this work, we present the result of a search for two-neutrino and neutrinoless double beta decays of $^{100}$Mo to the first 0$^+$ and $2^+$ excited states of $^{100}$Ru using the full CUPID-Mo exposure (2.71 kg$\times$yr of LMO). We measure the half-life of $2νββ$ decay to the $0^{+}_1$ state as $T_{1/2}^{2ν\rightarrow 0_1^+}=7.5\pm 0.8 \ \text{(stat.)} \ ^{+ 0.4}_{-0.3} \ \text{(syst.)} )\times 10^{20} \ \mathrm{yr}$. The bolometric technique enables measurement of the electron energies as well as the gamma rays from nuclear de-excitation and this allows us to set new limits on the two-neutrino decay to the $2_1^+$ state of $T^{2ν\rightarrow 2_1^+}_{1/2}>4.4\times 10^{21} \ \mathrm{yr} \ \text{(90 % c.i.)}$ and on the neutrinoless modes of $T_{1/2}^{0ν\rightarrow 2_1^+}>2.1\times10^{23} \ \mathrm{yr}\ \text{(90 % c.i.)}$, $T_{1/2}^{0ν\rightarrow 0_1^+}>1.2\times10^{23} \ \mathrm{yr}\ \text{(90 % c.i.)}$. Information on the electrons spectral shape is obtained which allows us to make the first comparison of the single state (SSD) and higher state (HSD) $2νββ$ decay models for the $0_1^+$ excited state of $^{100}$Ru.

nucl-ex↗

arXiv2022

First cryogenic tests on BINGO innovations

Neutrinoless double-beta decay ($0\nu2β$) is a hypothetical rare nuclear transition. Its observation would provide an important insight about the nature of neutrinos (Dirac or Majorana particle) demonstrating that the lepton number is not conserved. BINGO (Bi-Isotope $0\nu2β$ Next Generation Observatory) aims to set the technological grounds for future bolometric $0\nu2β$ experiments. It is based on a dual heat-light readout, i.e. a main scintillating absorber embedding the double-beta decay isotope accompanied by a cryogenic light detector. BINGO will study two of the most promising isotopes: $^{100}$Mo embedded in Li$_2$MoO$_4$ (LMO) crystals and $^{130}$Te embedded in TeO$_2$. BINGO technology will reduce dramatically the background in the region of interest, thus boosting the discovery sensitivity of $0\nu2β$. The proposed solutions will have a high impact on next-generation bolometric tonne-scale experiments, like CUPID. In this contribution, we present the results obtained during the first tests performed in the framework of BINGO R&D.

physics.ins-det↗

arXiv2021

New experimental limits on double-beta decay of osmium

Double-beta processes in $^{184}$Os and $^{192}$Os were searched for over 15851 h at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N. by using a 118 g ultra-pure osmium sample installed on the endcap of a 112 cm$^3$ ultra-low-background broad-energy germanium detector. New limits on double-electron capture and electron capture with positron emission in $^{184}$Os were set at the level of $\lim T_{1/2} \sim 10^{16}-10^{17}$ yr. In particular the $2ν$2K and $2ν$KL decays of $^{184}$Os to the ground state of $^{184}$W are restricted as $T_{1/2}\geq3.0\times 10^{16}$ yr and $T_{1/2}\geq2.0\times 10^{16}$ yr, respectively. A lower limit on the half-life for the double-beta decay of $^{192}$Os to the first excited level of $^{192}$Pt was set as $\lim T_{1/2}=2.0\times 10^{20}$ yr at 90\% C.L.

nucl-ex↗

arXiv2021

Calibration of nuclear recoils at the 100 eV scale using neutron capture

The development of low-threshold detectors for the study of coherent elastic neutrino-nucleus scattering and for the search for light dark matter necessitates methods of low-energy calibration. We suggest this can be provided by the nuclear recoils resulting from the $γ$ emission following thermal neutron capture. In particular, several MeV-scale single-$γ$ transitions induce well-defined nuclear recoil peaks in the 100 eV range. Using the FIFRELIN code, complete schemes of $γ$-cascades for various isotopes can be predicted with high accuracy to determine the continuous background of nuclear recoils below the calibration peaks. We present a comprehensive experimental concept for the calibration of CaWO$_4$ and Ge cryogenic detectors at a research reactor. For CaWO$_4$ the simulations show that two nuclear recoil peaks at 112.5 eV and 160.3 eV should be visible above background simply in the spectrum of the cryogenic detector. Then we discuss how the additional tagging for the associated $γ$ increases the sensitivity of the method and extends its application to a wider energy range and to Ge cryogenic detectors.

physics.ins-det↗

arXiv2021

Phonon-mediated crystal detectors with metallic film coating capable of rejecting $α$ and $β$ events induced by surface radioactivity

Phonon-mediated particle detectors based on single crystals and operated at millikelvin temperatures are used in rare-event experiments for neutrino physics and dark-matter searches. In general, these devices are not sensitive to the particle impact point, especially if the detection is mediated by thermal phonons. In this Letter, we demonstrate that excellent discrimination between interior and surface $β$ and $α$ events can be achieved by coating a crystal face with a thin metallic film, either continuous or in the form of a grid. The coating affects the phonon energy down-conversion cascade that follows the particle interaction, leading to a modified signal shape for close-to-film events. An efficient identification of surface events was demonstrated with detectors based on a rectangular $20 \times 20 \times 10$ mm$^3$ Li$_2$MoO$_4$ crystal coated with a Pd normal-metal film (10~nm thick) and with Al-Pd superconductive bi-layers (100~nm-10~nm thick) on a $20 \times 20$ mm$^2$ face. Discrimination capabilities were tested with $^{238}$U sources emitting both $α$ and $β$ particles. Surface events are identified for energy depositions down to millimeter-scale depths from the coated surface. With this technology, a substantial improvement of the background figure can be achieved in experiments searching for neutrinoless double-beta decay.

physics.ins-det↗

arXiv2021

New Limit for Neutrinoless Double-Beta Decay of $^{100}$Mo from the CUPID-Mo Experiment

The CUPID-Mo experiment at the Laboratoire Souterrain de Modane (France) is a demonstrator for CUPID, the next-generation ton-scale cryogenic $0νββ$ experiment. It consists of a 4.2 kg array of 20 enriched Li$_{2}$$^{100}$MoO$_4$ scintillating bolometers to search for the lepton number violating process of $0νββ$ decay in $^{100}$Mo. With more than one year of operation (2.16 kg$\times$yr of physics data), no event in the region of interest and hence no evidence for $0νββ$ is observed. We report a new limit on the half-life of $0νββ$ decay in $^{100}$Mo of $T_{1/2} > 1.5 \times 10^{24}\,$yr at 90 % C.I. The limit corresponds to an effective Majorana neutrino mass $\langle m_{ββ} \rangle$ $<$ (0.31--0.54)$\,$eV, dependent on the nuclear matrix element in the light Majorana neutrino exchange interpretation.

nucl-ex↗

arXiv2021

Pulse Shape Discrimination in CUPID-Mo using Principal Component Analysis

CUPID-Mo is a cryogenic detector array designed to search for neutrinoless double-beta decay ($0νββ$) of $^{100}$Mo. It uses 20 scintillating $^{100}$Mo-enriched Li$_2$MoO$_4$ bolometers instrumented with Ge light detectors to perform active suppression of $α$ backgrounds, drastically reducing the expected background in the $0νββ$ signal region. As a result, pileup events and small detector instabilities that mimic normal signals become non-negligible potential backgrounds. These types of events can in principle be eliminated based on their signal shapes, which are different from those of regular bolometric pulses. We show that a purely data-driven principal component analysis based approach is able to filter out these anomalous events, without the aid of detector response simulations.

physics.data-an↗

arXiv2021

Conceptual Design of BabyIAXO, the intermediate stage towards the International Axion Observatory

This article describes BabyIAXO, an intermediate experimental stage of the International Axion Observatory (IAXO), proposed to be sited at DESY. IAXO is a large-scale axion helioscope that will look for axions and axion-like particles (ALPs), produced in the Sun, with unprecedented sensitivity. BabyIAXO is conceived to test all IAXO subsystems (magnet, optics and detectors) at a relevant scale for the final system and thus serve as prototype for IAXO, but at the same time as a fully-fledged helioscope with relevant physics reach itself, and with potential for discovery. The BabyIAXO magnet will feature two 10 m long, 70 cm diameter bores, and will host two detection lines (optics and detector) of dimensions similar to the final ones foreseen for IAXO. BabyIAXO will detect or reject solar axions or ALPs with axion-photon couplings down to $g_{aγ} \sim 1.5 \times 10^{-11}$ GeV$^{-1}$, and masses up to $m_a\sim 0.25$ eV. BabyIAXO will offer additional opportunities for axion research in view of IAXO, like the development of precision x-ray detectors to identify particular spectral features in the solar axion spectrum, and the implementation of radiofrequency-cavity-based axion dark matter setups.

physics.ins-det↗

arXiv2020

Search for alpha decay of naturally occurring osmium nuclides accompanied by gamma quanta

A search for $α$ decay of naturally occurring osmium isotopes to the lowest excited levels of daughter nuclei has been performed by using an ultra-low-background Broad-Energy Germanium $γ$-detector with a volume of 112 cm$^3$ and an ultra-pure osmium sample with a mass of 118 g at the Gran Sasso National Laboratory of the INFN (Italy). The isotopic composition of the osmium sample has been measured with high precision using Negative Thermal Ionisation Mass Spectrometry. After 15851 h of data taking with the $γ$-detector no effect has been detected, and lower limits on the $α$ decays were set at level of $\lim T_{1/2}\sim 10^{15}-10^{19}$ yr. The limits for the $α$ decays of $^{184}$Os and $^{186}$Os to the first excited levels of daughter nuclei, $T_{1/2}(^{184}$Os$)\geq 6.8\times10^{15}$ yr and $T_{1/2}(^{186}$Os$)\geq3.3\times10^{17}$ yr (at 90% C.L.), exceed the present theoretical estimates of the decays half-lives. For $^{189}$Os and $^{192}$Os also decays to the ground states of the daughter nuclei were searched for due to the instability of the daughter nuclides relative to $β$ decay.

nucl-ex↗

arXiv2020

The CROSS Experiment: Rejecting Surface Events by PSD Induced by Superconducting Films

Neutrinoless double beta ($0νββ$) decay is a hypothetical rare nuclear transition ($T_{1/2}>10^{26}$ y). Its observation would provide an important insight about the nature of neutrinos (Dirac or Majorana particle) demonstrating that the lepton number is not conserved. This decay can be investigated with bolometers embedding the double beta decay isotope ($^{76}$Ge, $^{82}$Se, $^{100}$Mo, $^{116}$Cd, $^{130}$Te...), which perform as low temperature calorimeters (10 mK) detecting particle interactions via a small temperature rise read out by a dedicated thermometer. CROSS (Cryogenic Rare-event Observatory with Surface Sensitivity) aims at the development of bolometric detectors (Li$_{2}$MoO$_{4}$ and TeO$_{2}$) capable of discriminating surface $α$ and $β$ interactions by exploiting superconducting properties of Al film deposited on the crystal surface. We report in this paper the results of tests on prototypes performed at CSNSM (Orsay, France) that showed the capability of a-few-$μ$m-thick superconducting Al film deposited on crystal surface to discriminate surface $α$ from bulk events, thus providing the detector with the required surface sensitivity capability. The CROSS technology would further improve the background suppression and simplify the detector construction with a view to future competitive double beta decay searches.

physics.ins-det↗

arXiv2019

Precise measurement of $2νββ$ decay of $^{100}$Mo with the CUPID-Mo detection technology

We report the measurement of the two-neutrino double-beta ($2νββ$) decay of $^{100}$Mo to the ground state of $^{100}$Ru using lithium molybdate (\crystal) scintillating bolometers. The detectors were developed for the CUPID-Mo program and operated at the EDELWEISS-III low background facility in the Modane underground laboratory. From a total exposure of $42.235$ kg$\times$d, the half-life of $^{100}$Mo is determined to be $T_{1/2}^{2ν}=[7.12^{+0.18}_{-0.14}\,\mathrm{(stat.)}\pm0.10\,\mathrm{(syst.)}]\times10^{18}$ years. This is the most accurate determination of the $2νββ$ half-life of $^{100}$Mo to date. We also confirm, with the statistical significance of $>3σ$, that the single-state dominance model of the $2νββ$ decay of $^{100}$Mo is favored over the high-state dominance model.

nucl-ex↗

arXiv2019

First data from the CUPID-Mo neutrinoless double beta decay experiment

The CUPID-Mo experiment is searching for neutrinoless double beta decay in $^{100}$Mo, evaluating the technology of cryogenic scintillating Li$_{2}^{100}$MoO$_4$ detectors for CUPID (CUORE Upgrade with Particle ID). CUPID-Mo detectors feature background suppression using a dual-readout scheme with Li$_{2}$MoO$_4$ crystals complemented by Ge bolometers for light detection. The detection of both heat and scintillation light signals allows the efficient discrimination of $α$ from $γ$&$β$ events. In this proceedings, we discuss results from the first 2 months of data taking in spring 2019. In addition to an excellent bolometric performance of 6.7$\,$keV (FWHM) at 2615$\,$keV and an $α$ separation of better than 99.9\% for all detectors, we report on bulk radiopurity for Th and U. Finally, we interpret the accumulated physics data in terms of a limit of $T_{1/2}^{0ν}\,> 3\times10^{23}\,$yr for $^{100}$Mo and discuss the sensitivity of CUPID-Mo until the expected end of physics data taking in early 2020.

hep-ex↗