Showing 1–50 of 102 results for author: Sisti, M

Real-Time Wiener Deconvolution for feature reconstruction in JUNO

Authors: L. Lastrucci, M. Grassi, A. Triossi, J. Hu, X. Jiang, R. Brugnera, A. Garfagnini, V. Cerrone, L. V. D'Auria, A. Gavrikov, R. M. Guizzetti, A. Serafini, G. Andronico, V. Antonelli, A. Barresi, D. Basilico, M. Beretta, A. Bergnoli, M. Borghesi, A. Brigatti, R. Bruno, A. Budano, B. Caccianiga, A. Cammi, R. Caruso , et al. (52 additional authors not shown)

Abstract: In particle physics, experiments generate substantial amounts of data that can be difficult to process without preliminary scaling. To avoid losing potentially crucial data, experimental collaborations are studying novel techniques for real-time data processing to extract features for further physics analysis. A common approach, especially in neutrino physics, is to use FPGAs for data acquisition… ▽ More In particle physics, experiments generate substantial amounts of data that can be difficult to process without preliminary scaling. To avoid losing potentially crucial data, experimental collaborations are studying novel techniques for real-time data processing to extract features for further physics analysis. A common approach, especially in neutrino physics, is to use FPGAs for data acquisition and pre-processing. This paper presents an advanced Real-Time Wiener deconvolution algorithm designed to leverage the processing capabilities of the FPGA integrated into the readout boards of the Jiangmen Underground Neutrino Observatory (JUNO). The goal is to enable real-time reconstruction of the signal generated by photomultiplier tubes (PMTs) when neutrino interactions are detected. By exploiting online reconstruction of the signal generated by PMTs, we expect to improve the detection of low-energy depositions, such as those produced by transient astrophysical phenomena. These depositions are usually not saved because of the significant background that affects the low end of the energy spectrum, which would result in a large trigger rate, hence a large amount of data required for storage. This paper presents the features of the algorithm, including its ability to manage high-throughput data streams with minimal latency, adaptability, and resilience in discerning the characteristics of input data. Performance is evaluated on a JUNO electronic board. This study further demonstrates the potential of FPGA-based solutions for neutrino physics. △ Less

Submitted 26 March, 2026; originally announced March 2026.

Ultra-trace analysis of U and Th in organic liquid scintillators with high sensitivity

Authors: A. Barresi, D. Chiesa, D. Merli, M. Nastasi, S. Nisi, E. Previtali, M. Sisti, M. Borghesi, A. Cammi, C. Coletta, G. Ferrante, L. Loi, G. Andronico, V. Antonelli, D. Basilico, M. Beretta, A. Bergnoli, A. Brigatti, R. Brugnera, R. Bruno, A. Budano, B. Caccianiga, V. Cerrone, R. Caruso, C. Clementi , et al. (41 additional authors not shown)

Abstract: Rare event searches demand extremely low background levels, necessitating ever-advancing screening techniques to enhance sensitivity. Liquid scintillators are highly attractive as detector media due to their inherent radiopurity and scalability in mass. In this work, we present a screening procedure to measure ultra-trace concentrations of natural contaminants -- $^{238}$U and $^{232}$Th -- with s… ▽ More Rare event searches demand extremely low background levels, necessitating ever-advancing screening techniques to enhance sensitivity. Liquid scintillators are highly attractive as detector media due to their inherent radiopurity and scalability in mass. In this work, we present a screening procedure to measure ultra-trace concentrations of natural contaminants -- $^{238}$U and $^{232}$Th -- with sensitivities at the \qty{E-15}{g/g} level. Our method combines neutron activation analysis with radiochemical techniques, followed by \bg\ coincidence spectroscopy to minimize interference backgrounds. This approach achieves sensitivities of \qty{0.65E-15}{g/g} for $^{238}$U and \qty{2.3E-15}{g/g} for $^{232}$Th, among the best reported worldwide. Potential pathways for further sensitivity improvements are outlined in the conclusions. △ Less

Submitted 6 December, 2025; originally announced December 2025.

Initial performance results of the JUNO detector

Authors: Angel Abusleme, Thomas Adam, Kai Adamowicz, David Adey, Shakeel Ahmad, Rizwan Ahmed, Timo Ahola, Sebastiano Aiello, Fengpeng An, Guangpeng An, Costas Andreopoulos, Giuseppe Andronico, João Pedro Athayde Marcondes de André, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, Didier Auguste, Margherita Buizza Avanzini, Andrej Babic, Jingzhi Bai, Weidong Bai, Nikita Balashov, Roberto Barbera, Andrea Barresi , et al. (1114 additional authors not shown)

Abstract: The Jiangmen Underground Neutrino Observatory (JUNO) started physics data taking on 26 August 2025. JUNO consists of a 20-kton liquid scintillator central detector, surrounded by a 35 kton water pool serving as a Cherenkov veto, and almost 1000 m$^2$ of plastic scintillator veto on top. The detector is located in a shallow underground laboratory with an overburden of 1800 m.w.e. This paper present… ▽ More The Jiangmen Underground Neutrino Observatory (JUNO) started physics data taking on 26 August 2025. JUNO consists of a 20-kton liquid scintillator central detector, surrounded by a 35 kton water pool serving as a Cherenkov veto, and almost 1000 m$^2$ of plastic scintillator veto on top. The detector is located in a shallow underground laboratory with an overburden of 1800 m.w.e. This paper presents the performance results of the detector, extensively studied during the commissioning of the water phase, the subsequent liquid scintillator filling phase, and the first physics runs. The liquid scintillator achieved an attenuation length of 20.6 m at 430 nm, while the high coverage PMT system and scintillator together yielded about 1785 photoelectrons per MeV of energy deposit at the detector centre, measured using the 2.223 MeV $γ$ from neutron captures on hydrogen with an Am-C calibration source. The reconstructed energy resolution is 3.4% for two 0.511 MeV $γ$ at the detector centre and 2.9% for the 0.93 MeV quenched Po-214 alpha decays from natural radioactive sources. The energy nonlinearity is calibrated to better than 1%. Intrinsic contaminations of U-238 and Th-232 in the liquid scintillator are below 10$^{-16}$ g/g, assuming secular equilibrium. The water Cherenkov detector achieves a muon detection efficiency better than 99.9% for muons traversing the liquid scintillator volume. During the initial science runs, the data acquisition duty cycle exceeded 97.8%, demonstrating the excellent stability and readiness of JUNO for high-precision neutrino physics. △ Less

Submitted 18 November, 2025; originally announced November 2025.

Comments: 38 pages, 23 figures

Prospects for geoneutrino detection with JUNO

Authors: Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Fengpeng An, João Pedro Athayde Marcondes de André, Costas Andreopoulos, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Didier Auguste, Marcel Büchner, Weidong Bai, Nikita Balashov, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Beretta, Antonio Bergnoli, Nikita Bessonov, Daniel Bick, Lukas Bieger, Svetlana Biktemerova, Thilo Birkenfeld, Simon Blyth , et al. (605 additional authors not shown)

Abstract: Geoneutrinos, which are antineutrinos emitted during the decay of long-lived radioactive elements inside Earth, serve as a unique tool for studying the composition and heat budget of our planet. The Jiangmen Underground Neutrino Observatory (JUNO) experiment in China, which has recently completed construction, is expected to collect a sample comparable in size to the entire existing world geoneutr… ▽ More Geoneutrinos, which are antineutrinos emitted during the decay of long-lived radioactive elements inside Earth, serve as a unique tool for studying the composition and heat budget of our planet. The Jiangmen Underground Neutrino Observatory (JUNO) experiment in China, which has recently completed construction, is expected to collect a sample comparable in size to the entire existing world geoneutrino dataset in less than a year. This paper presents an updated estimation of sensitivity to geoneutrinos of JUNO using the best knowledge available to date about the experimental site, the surrounding nuclear reactors, the detector response uncertainties, and the constraints expected from the TAO satellite detector. To facilitate comparison with present and future geological models, our results cover a wide range of predicted signal strengths. Despite the significant background from reactor antineutrinos, the experiment will measure the total geoneutrino flux with a precision comparable to that of existing experiments within its first few years, ultimately achieving a world-leading precision of about 8% over ten years. The large statistics of JUNO will also allow separation of the Uranium-238 and Thorium-232 contributions with unprecedented precision, providing crucial constraints on models of formation and composition of Earth. Observation of the mantle signal above the lithospheric flux will be possible but challenging. For models with the highest predicted mantle concentrations of heat-producing elements, a 3-sigma detection over six years requires knowledge of the lithospheric flux to within 15%. Together with complementary measurements from other locations, the geoneutrino results of JUNO will offer cutting-edge, high-precision insights into the interior of Earth, of fundamental importance to both the geoscience and neutrino physics communities. △ Less

Submitted 10 November, 2025; originally announced November 2025.

Comments: 32 pages, with 13 figures and 5 tables

Design, waterproofing, and mass production of the 3-inch PMT frontend system of JUNO

Authors: Jilei Xu, Miao He, Cédric Cerna, Yongbo Huang, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Fengpeng An, Costas Andreopoulos, Giuseppe Andronico, João Pedro Athayde Marcondes de André, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Didier Auguste, Weidong Bai, Nikita Balashov, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Beretta, Antonio Bergnoli, Nikita Bessonov, Daniel Bick, Lukas Bieger , et al. (609 additional authors not shown)

Abstract: Over 25,600 3-inch photomultiplier tubes (PMTs) have been instrumented for the central detector of the Jiangmen Underground Neutrino Observatory. Each PMT is equipped with a high-voltage divider and a frontend cable with waterproof sealing. Groups of sixteen PMTs are connected to the underwater frontend readout electronics via specialized multi-channel waterproof connectors. This paper outlines th… ▽ More Over 25,600 3-inch photomultiplier tubes (PMTs) have been instrumented for the central detector of the Jiangmen Underground Neutrino Observatory. Each PMT is equipped with a high-voltage divider and a frontend cable with waterproof sealing. Groups of sixteen PMTs are connected to the underwater frontend readout electronics via specialized multi-channel waterproof connectors. This paper outlines the design and mass production processes for the high-voltage divider, the cable and connector, as well as the waterproof potting of the PMT bases. The results of the acceptance tests of all the integrated PMTs are also presented. △ Less

Submitted 22 January, 2026; v1 submitted 7 October, 2025; originally announced October 2025.

Reconstruction of cosmic-ray muon events with CUORE

Authors: CUORE Collaboration, D. Q. Adams, C. Alduino, K. Alfonso, A. Armatol, F. T. Avignone III, O. Azzolini, G. Bari, F. Bellini, G. Benato, M. Beretta, M. Biassoni, A. Branca, D. Brandani, C. Brofferio, C. Bucci, J. Camilleri, A. Caminata, A. Campani, J. Cao, S. Capelli, L. Cappelli, L. Cardani, P. Carniti, N. Casali , et al. (96 additional authors not shown)

Abstract: We report the in-situ 3D reconstruction of through-going muons in the CUORE experiment, a cryogenic calorimeter array searching for neutrinoless double beta ($0νββ$) decay, leveraging the segmentation of the detector. Due to the slow time response of the detector, time-of-flight estimation is not feasible. Therefore, the track reconstruction is performed using a multi-objective optimization algori… ▽ More We report the in-situ 3D reconstruction of through-going muons in the CUORE experiment, a cryogenic calorimeter array searching for neutrinoless double beta ($0νββ$) decay, leveraging the segmentation of the detector. Due to the slow time response of the detector, time-of-flight estimation is not feasible. Therefore, the track reconstruction is performed using a multi-objective optimization algorithm that relies on geometrical information from the detector as a whole. We measure the integral flux of cosmic-ray muons underground at the {\it Laboratori Nazionali del Gran Sasso}, and find our value to be in good agreement with other experiments that have performed a similar measurement. To our knowledge, this work represents the first demonstration of 3D particle tracking and reconstruction of through-going muons with per-event angular determination in a millikelvin cryogenic detector array. The analysis performed for this work will be critical for validating the muon-related background in CUPID, a next-generation $0νββ$ experiment, and for follow-up studies on detector response and on delayed products induced by cosmic-ray muons. △ Less

Submitted 5 September, 2025; originally announced September 2025.

Simulation-based inference for Precision Neutrino Physics through Neural Monte Carlo tuning

Authors: A. Gavrikov, A. Serafini, D. Dolzhikov, A. Garfagnini, M. Gonchar, M. Grassi, R. Brugnera, V. Cerrone, L. V. D'Auria, R. M. Guizzetti, L. Lastrucci, G. Andronico, V. Antonelli, A. Barresi, D. Basilico, M. Beretta, A. Bergnoli, M. Borghesi, A. Brigatti, R. Bruno, A. Budano, B. Caccianiga, A. Cammi, R. Caruso, D. Chiesa , et al. (41 additional authors not shown)

Abstract: Precise modeling of detector energy response is crucial for next-generation neutrino experiments which present computational challenges due to lack of analytical likelihoods. We propose a solution using neural likelihood estimation within the simulation-based inference framework. We develop two complementary neural density estimators that model likelihoods of calibration data: conditional normaliz… ▽ More Precise modeling of detector energy response is crucial for next-generation neutrino experiments which present computational challenges due to lack of analytical likelihoods. We propose a solution using neural likelihood estimation within the simulation-based inference framework. We develop two complementary neural density estimators that model likelihoods of calibration data: conditional normalizing flows and a transformer-based regressor. We adopt JUNO - a large neutrino experiment - as a case study. The energy response of JUNO depends on several parameters, all of which should be tuned, given their non-linear behavior and strong correlations in the calibration data. To this end, we integrate the modeled likelihoods with Bayesian nested sampling for parameter inference, achieving uncertainties limited only by statistics with near-zero systematic biases. The normalizing flows model enables unbinned likelihood analysis, while the transformer provides an efficient binned alternative. By providing both options, our framework offers flexibility to choose the most appropriate method for specific needs. Finally, our approach establishes a template for similar applications across experimental neutrino and broader particle physics. △ Less

Submitted 31 July, 2025; originally announced July 2025.

Quantitative U/Th deposition and cleanliness control strategies in the JUNO site air

Authors: Jie Zhao, Chenyang Cui, Yongpeng Zhang, Gaosong Li, Nan Wang, Monica Sisti

Abstract: The Jiangmen Underground Neutrino Observatory (JUNO) employs a 20 kt liquid scintillator (LS) detector located 700 m underground. To meet its physics objectives, the LS must achieve an ultra-low $^{238}$U/$^{232}$Th content of 10$^{-17}$ g/g. Given that airborne dust exhibits radioactivity about 12 orders of magnitude higher, exceptional cleanliness is essential during on-site installation. The to… ▽ More The Jiangmen Underground Neutrino Observatory (JUNO) employs a 20 kt liquid scintillator (LS) detector located 700 m underground. To meet its physics objectives, the LS must achieve an ultra-low $^{238}$U/$^{232}$Th content of 10$^{-17}$ g/g. Given that airborne dust exhibits radioactivity about 12 orders of magnitude higher, exceptional cleanliness is essential during on-site installation. The total permissible dust mass in the 20 kt LS is only about 8 mg. To attain this, the acrylic vessel interior must comply with class 1,000 cleanliness. Pre-filling water spray cleaning improves cleanliness by roughly two orders of magnitude, requiring the overall environment to be maintained between class 10,000 and 100,000. At JUNO, a cleanroom management system has been implemented across the 120,000 m$^3$ underground experimental hall. Since May 2022, continuous laser particle monitoring has consistently achieved an average cleanliness class of 74,000. Furthermore, we developed a method to directly measure $^{238}$U/$^{232}$Th deposition rates on detector surfaces. Using ICP-MS, sensitivity reaches sub-ppt levels ($<$10$^{-12}$ g/g), enabling effective cleanliness control and assessment of external contamination during detector construction. △ Less

Submitted 3 March, 2026; v1 submitted 8 July, 2025; originally announced July 2025.

Exploring the keV-scale physics potential of CUORE

Authors: CUORE Collaboration, D. Q. Adams, C. Alduino, K. Alfonso, A. Armatol, F. T. Avignone III, O. Azzolini, G. Bari, F. Bellini, G. Benato, M. Beretta, M. Biassoni, A. Branca, C. Brofferio, C. Bucci, J. Camilleri, A. Caminata, A. Campani, J. Cao, C. Capelli, S. Capelli, L. Cappelli, L. Cardani, P. Carniti, N. Casali , et al. (98 additional authors not shown)

Abstract: We present the analysis techniques developed to explore the keV-scale energy region of the CUORE experiment, based on more than 2 tonne yr of data collected over 5 years. By prioritizing a stricter selection over a larger exposure, we are able to optimize data selection for thresholds at 10 keV and 3 keV with 691 kg yr and 11 kg yr of data, respectively. We study how the performance varies among t… ▽ More We present the analysis techniques developed to explore the keV-scale energy region of the CUORE experiment, based on more than 2 tonne yr of data collected over 5 years. By prioritizing a stricter selection over a larger exposure, we are able to optimize data selection for thresholds at 10 keV and 3 keV with 691 kg yr and 11 kg yr of data, respectively. We study how the performance varies among the 988-detector array with different detector characteristics and data taking conditions. We achieve an average baseline resolution of 2.54 $\pm$ 0.14 keV FWHM and 1.18 $\pm$ 0.02 keV FWHM for the data selection at 10 keV and 3 keV, respectively. The analysis methods employed reduce the overall background by about an order of magnitude, reaching 2.06 $\pm$ 0.05 counts/(keV kg days) and 16 $\pm$ 2 counts/(keV kg days) at the thresholds of 10 keV and 3 keV. We evaluate for the first time the near-threshold reconstruction efficiencies of the CUORE experiment, and find these to be 26 $\pm$ 4 \% and 50 $\pm$ 2 \% at 3 keV and 10 keV, respectively. This analysis provides crucial insights into rare decay studies, new physics searches, and keV-scale background modeling with CUORE. We demonstrate that tonne-scale cryogenic calorimeters can operate across a wide energy range, from keV to MeV, establishing their scalability as versatile detectors for rare event and dark matter physics. These findings also inform the optimization of future large mass cryogenic calorimeters to enhance the sensitivity to low-energy phenomena. △ Less

Submitted 4 February, 2026; v1 submitted 29 May, 2025; originally announced May 2025.

First-ever detection of microseismic activity with a tonne-scale cryogenic experiment

Authors: D. Q. Adams, C. Alduino, K. Alfonso, A. Armatol, F. T. Avignone, O. Azzolini, G. Bari, F. Bellini, G. Benato, M. Beretta, M. Biassoni, A. Branca, C. Brofferio, C. Bucci, J. Camilleri, A. Caminata, A. Campani, J. Cao, C. Capelli, S. Capelli, L. Cappelli, L. Cardani, P. Carniti, N. Casali, E. Celi , et al. (105 additional authors not shown)

Abstract: Vibrations from experimental setups and the environment are a persistent source of noise for low-temperature calorimeters searching for rare events, including neutrinoless double beta ($0νββ$) decay or dark matter interactions. Such noise can significantly limit experimental sensitivity to the physics case under investigation. Here we report the first detection of marine microseismic vibrations us… ▽ More Vibrations from experimental setups and the environment are a persistent source of noise for low-temperature calorimeters searching for rare events, including neutrinoless double beta ($0νββ$) decay or dark matter interactions. Such noise can significantly limit experimental sensitivity to the physics case under investigation. Here we report the first detection of marine microseismic vibrations using mK-scale calorimeters. This study employs a multi-device analysis correlating data from CUORE, the leading experiment in the search for $0νββ$ decay with mK-scale calorimeters and the Copernicus Earth Observation program, revealing the seasonal impact of Mediterranean Sea activity on CUORE's energy thresholds, resolution, and sensitivity over four years. The detection of marine microseisms underscores the need to address faint environmental noise in ultra-sensitive experiments. Understanding how such noise couples to the detector and developing mitigation strategies is essential for next-generation experiments. We demonstrate one such strategy: a noise decorrelation algorithm implemented in CUORE using auxiliary sensors, which reduces vibrational noise and improves detector performance. Enhancing sensitivity to $0νββ$ decay and to rare events with low-energy signatures requires identifying unresolved noise sources, advancing noise reduction methods, and improving vibration suppression systems, all of which inform the design of next-generation rare event experiments. △ Less

Submitted 13 May, 2025; originally announced May 2025.

Innovating Bolometers' Mounting: A Gravity-Based Approach

Authors: The CUPID Collaboration, K. Alfonso, A. Armatol, C. Augier, F. T. Avignone III, O. Azzolini, A. S. Barabash, G. Bari, A. Barresi, D. Baudin, F. Bellini, G. Benato, L. Benussi, V. Berest, M. Beretta, M. Bettelli, M. Biassoni, J. Billard, F. Boffelli, V. Boldrini, E. D. Brandani, C. Brofferio, C. Bucci, M. Buchynska, J. Camilleri , et al. (168 additional authors not shown)

Abstract: Cryogenic calorimeters, also known as bolometers, are among the leading technologies for searching for rare events. The CUPID experiment is exploiting this technology to deploy a tonne-scale detector to search for neutrinoless double-beta decay of $^{100}$Mo. The CUPID collaboration proposed an innovative approach to assembling bolometers in a stacked configuration, held in position solely by grav… ▽ More Cryogenic calorimeters, also known as bolometers, are among the leading technologies for searching for rare events. The CUPID experiment is exploiting this technology to deploy a tonne-scale detector to search for neutrinoless double-beta decay of $^{100}$Mo. The CUPID collaboration proposed an innovative approach to assembling bolometers in a stacked configuration, held in position solely by gravity. This gravity-based assembly method is unprecedented in the field of bolometers and offers several advantages, including relaxed mechanical tolerances and simplified construction. To assess and optimize its performance, we constructed a medium-scale prototype hosting 28 Li$_2$MoO$_4$ crystals and 30 Ge light detectors, both operated as cryogenic calorimeters at the Laboratori Nazionali del Gran Sasso (Italy). Despite an unexpected excess of noise in the light detectors, the results of this test proved (i) a thermal stability better than $\pm$0.5 mK at 10 mK, (ii) a good energy resolution of Li$_2$MoO$_4$ bolometers, (6.6 $\pm$ 2.2) keV FWHM at 2615 keV, and (iii) a Li$_2$MoO$_4$ light yield measured by the closest light detector of 0.36 keV/MeV, sufficient to guarantee the particle identification requested by CUPID. △ Less

Submitted 6 March, 2025; originally announced March 2025.

CUPID, the CUORE Upgrade with Particle IDentification

Authors: The CUPID Collaboration, K. Alfonso, A. Armatol, C. Augier, F. T. Avignone III, O. Azzolini, A. S. Barabash, G. Bari, A. Barresi, D. Baudin, F. Bellini, G. Benato, L. Benussi, V. Berest, M. Beretta, L. Bergé, M. Bettelli, M. Biassoni, J. Billard, F. Boffelli, V. Boldrini, E. D. Brandani, C. Brofferio, C. Bucci, M. Buchynska , et al. (168 additional authors not shown)

Abstract: CUPID, the CUORE Upgrade with Particle IDentification, is a next-generation experiment to search for neutrinoless double beta decay ($0νββ$) and other rare events using enriched Li$_2$$^{100}$MoO$_4$ scintillating bolometers. It will be hosted by the CUORE cryostat located at the Laboratori Nazionali del Gran Sasso in Italy. The main physics goal of CUPID is to search for $0νββ$\ of $^{100}$Mo wit… ▽ More CUPID, the CUORE Upgrade with Particle IDentification, is a next-generation experiment to search for neutrinoless double beta decay ($0νββ$) and other rare events using enriched Li$_2$$^{100}$MoO$_4$ scintillating bolometers. It will be hosted by the CUORE cryostat located at the Laboratori Nazionali del Gran Sasso in Italy. The main physics goal of CUPID is to search for $0νββ$\ of $^{100}$Mo with a discovery sensitivity covering the full neutrino mass regime in the inverted ordering scenario, as well as the portion of the normal ordering regime with lightest neutrino mass larger than 10 meV. With a conservative background index of 10$^{-4}$ cnts/(keV$\cdot$kg$\cdot$yr), 240 kg isotope mass, 5 keV FWHM energy resolution at 3 MeV and 10 live-years of data taking, CUPID will have a 90\% C.L. half-life exclusion sensitivity of 1.8 $\cdot$ 10$^{27}$ yr, corresponding to an effective Majorana neutrino mass ($m_{ββ}$) sensitivity of 9--15 meV, and a $3σ$ discovery sensitivity of 1 $\cdot$ 10$^{27}$ yr, corresponding to an $m_{ββ}$ range of 12--21 meV. △ Less

Submitted 11 July, 2025; v1 submitted 1 March, 2025; originally announced March 2025.

Comments: Accepted for publication by EPJC; 25 pages, 6 figures, and 2 tables

Journal ref: Eur. Phys. J. C 85, 737 (2025)

Simulation of the Background from $^{13}$C$(α, n)^{16}$O Reaction in the JUNO Scintillator

Authors: JUNO Collaboration, Thomas Adam, Kai Adamowicz, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Fengpeng An, Costas Andreopoulos, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, João Pedro Athayde Marcondes de André, Didier Auguste, Weidong Bai, Nikita Balashov, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Beretta, Antonio Bergnoli, Nikita Bessonov, Daniel Bick, Lukas Bieger, Svetlana Biktemerova , et al. (608 additional authors not shown)

Abstract: Large-scale organic liquid scintillator detectors are highly efficient in the detection of MeV-scale electron antineutrinos. These signal events can be detected through inverse beta decay on protons, which produce a positron accompanied by a neutron. A noteworthy background for antineutrinos coming from nuclear power reactors and from the depths of the Earth (geoneutrinos) is generated by ($α, n$)… ▽ More Large-scale organic liquid scintillator detectors are highly efficient in the detection of MeV-scale electron antineutrinos. These signal events can be detected through inverse beta decay on protons, which produce a positron accompanied by a neutron. A noteworthy background for antineutrinos coming from nuclear power reactors and from the depths of the Earth (geoneutrinos) is generated by ($α, n$) reactions. In organic liquid scintillator detectors, $α$ particles emitted from intrinsic contaminants such as $^{238}$U, $^{232}$Th, and $^{210}$Pb/$^{210}$Po, can be captured on $^{13}$C nuclei, followed by the emission of a MeV-scale neutron. Three distinct interaction mechanisms can produce prompt energy depositions preceding the delayed neutron capture, leading to a pair of events correlated in space and time within the detector. Thus, ($α, n$) reactions represent an indistinguishable background in liquid scintillator-based antineutrino detectors, where their expected rate and energy spectrum are typically evaluated via Monte Carlo simulations. This work presents results from the open-source SaG4n software, used to calculate the expected energy depositions from the neutron and any associated de-excitation products. Also simulated is a detailed detector response to these interactions, using a dedicated Geant4-based simulation software from the JUNO experiment. An expected measurable $^{13}$C$(α, n)^{16}$O event rate and reconstructed prompt energy spectrum with associated uncertainties, are presented in the context of JUNO, however, the methods and results are applicable and relevant to other organic liquid scintillator neutrino detectors. △ Less

Submitted 2 May, 2025; v1 submitted 2 March, 2025; originally announced March 2025.

Comments: 25 pages, 14 figures, 4 tables

Implementation of a high-efficiency muon veto system for the GeSparK alpha-beta/gamma coincidence detector

Authors: A. Barresi, D. Chiesa, M. Nastasi, E. Previtali, M. Sisti

Abstract: One of the main background sources of low background high purity germanium (HPGe) detectors is the cosmic muon showers produced in the interaction with the lead and copper shield surrounding the detector that can induce signals not distinguishable from radioactivity events. Plastic scintillators are widely used to implement active veto systems to reduce this contribution and increase the measureme… ▽ More One of the main background sources of low background high purity germanium (HPGe) detectors is the cosmic muon showers produced in the interaction with the lead and copper shield surrounding the detector that can induce signals not distinguishable from radioactivity events. Plastic scintillators are widely used to implement active veto systems to reduce this contribution and increase the measurement sensitivity. In this work, we present the implementation of a high-efficiency muon veto system for the alpha-beta/gamma coincidence detector, called GeSparK. The veto system consists of six plastic scintillator detectors accurately positioned around the HPGe and liquid scintillator detectors. The final design includes two detectors above and four inside the passive shielding between the copper and lead layers. In this way, we could limit both their size and the event rate produced by external radioactivity. A dedicated background measurement showed that the achieved background reduction is a bit less than 93%. △ Less

Submitted 17 February, 2025; originally announced February 2025.

Fluorescence emission of the JUNO liquid scintillator

Authors: M. Beretta, F. Houria, F. Ferraro, D. Basilico, A. Brigatti, B. Caccianiga, A. Caslini, C. Landini, P. Lombardi, L. Pelicci, E. Percalli, G. Ranucci, A. C. Re, C. Clementi, F. Ortica, A. Romani, V. Antonelli, M. G. Giammarchi, L. Miramonti, P. Saggese, M. D. C. Torri, S. Aiello, G. Andronico, A. Barresi, A. Bergnoli , et al. (43 additional authors not shown)

Abstract: JUNO is a huge neutrino detector that will use 20 kton of organic liquid scintillator as its detection medium. The scintillator is a mixture of linear alkyl benzene (LAB), 2.5 g/L of 2,5-diphenyloxazole (PPO) and 3 mg/L of 1,4-Bis(2-methylstyryl)benzene (Bis-MSB). The main goal of JUNO is to determine the Neutrino Mass Ordering [1, 2, 3]. In order to achieve this purpose, good energy and position… ▽ More JUNO is a huge neutrino detector that will use 20 kton of organic liquid scintillator as its detection medium. The scintillator is a mixture of linear alkyl benzene (LAB), 2.5 g/L of 2,5-diphenyloxazole (PPO) and 3 mg/L of 1,4-Bis(2-methylstyryl)benzene (Bis-MSB). The main goal of JUNO is to determine the Neutrino Mass Ordering [1, 2, 3]. In order to achieve this purpose, good energy and position reconstruction is required, hence a complete understanding of the optical characteristics of the liquid scintillator is mandatory. In this paper we present the measurements on the JUNO scintillator emission spectrum, absorption length and fluorescence time distribution performed respectively with a spectrofluorimeter, a spectrophotometer and a custom made setup △ Less

Submitted 9 March, 2025; v1 submitted 17 January, 2025; originally announced January 2025.

Journal ref: Journal of Instrumentation, Volume 20, May 2025

Machine learning-assisted techniques for Compton-background discrimination in Broad Energy Germanium (BEGe) detector

Authors: Giovanni Baccolo, Andrea Barresi, Davide Chiesa, Andrea Giachero, Danilo Labranca, Roberto Moretti, Massimiliano Nastasi, Alessandro Paonessa, Marco Picione, Ezio Previtali, Monica Sisti

Abstract: High Purity Germanium (HPGe) detectors are powerful detectors for gamma-ray spectroscopy. The sensitivity to low-intensity gamma-ray peaks is often hindered by the presence of Compton continuum distributions, originated by gamma-rays emitted at higher energies. This study explores novel, pulse shape-based, machine learning-assisted techniques to enhance Compton background discrimination in Broad E… ▽ More High Purity Germanium (HPGe) detectors are powerful detectors for gamma-ray spectroscopy. The sensitivity to low-intensity gamma-ray peaks is often hindered by the presence of Compton continuum distributions, originated by gamma-rays emitted at higher energies. This study explores novel, pulse shape-based, machine learning-assisted techniques to enhance Compton background discrimination in Broad Energy Germanium (BEGe TM) detectors. We introduce two machine learning models: an autoencoder-MLP (Multilayer Perceptron) and a Gaussian Mixture Model (GMM). These models differentiate single-site events (SSEs) from multi-site events (MSEs) and train on signal waveforms produced in the detector. The GMM method differs from previous machine learning efforts in that it is fully unsupervised, hence not requiring specific data labelling during the training phase. Being both label-free and simulation-agnostic makes the unsupervised approach particularly advantageous for tasks where realistic, high-fidelity labeling is challenging or where biases introduced by simulated data must be avoided. In our analysis, the full-energy Peak-to-Compton ratio of the 137-Cs, a radionuclide contained in a cryoconite sample, exhibits an improvement from 0.238 in the original spectrum to 0.547 after the ACM data filtering and 0.414 after the GMM data filtering, demonstrating the effectiveness of these methods. The results also showcase an enhancement in the signal-to-background ratio across many regions of interest, enabling the detection of lower concentrations of radionuclides. △ Less

Submitted 11 December, 2024; originally announced December 2024.

Comments: Sumbitted to EPJC

Radiopurity screening of materials for rare event searches by neutron activation at the TRIGA reactor of Pavia

Authors: G. Baccolo, A. Barresi, D. Chiesa, M. Nastasi, E. Previtali, M. Sisti

Abstract: In the framework of physics experiments searching for rare events, the selection of extremely radiopure materials is a challenging task, as the signal of interest is often hidden by instrumental background. Neutron activation is a powerful technique to measure trace contaminants with high sensitivity but, to be properly applied, it requires a good characterization of neutron irradiation and $γ$-sp… ▽ More In the framework of physics experiments searching for rare events, the selection of extremely radiopure materials is a challenging task, as the signal of interest is often hidden by instrumental background. Neutron activation is a powerful technique to measure trace contaminants with high sensitivity but, to be properly applied, it requires a good characterization of neutron irradiation and $γ$-spectroscopy facilities. This paper presents the state-of-the-art workflow adopted by the Radioactivity Laboratory of the University of Milano-Bicocca for radiopurity screening of materials by neutron activation performed at the TRIGA reactor in Pavia. The ultimate sensitivity of the described workflow, in the absence of interfering activation products and without the application of radiochemical and/or active background rejection techniques, is $<10^{-14}$ g/g for $^{40}$K, $<10^{-12}$ g/g for $^{238}$U and of the order of $10^{-12}$ g/g for $^{232}$Th contaminations. Further details are here provided to address systematic uncertainties related to neutron irradiation that may bias results. To this aim, a dedicated neutron activation campaign was performed and the data were analyzed exploiting a Monte Carlo simulation model of the reactor and applying an unfolding technique to obtain a comprehensive characterization of the neutron flux in typical irradiation configurations. The results of this work provide a valuable benchmark for the application of neutron activation in future radiopurity screening campaigns. △ Less

Submitted 6 October, 2025; v1 submitted 4 November, 2024; originally announced November 2024.

Comments: This version of the article has been accepted for publication after peer review, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections

Journal ref: Eur. Phys. J. Plus 140, 311 (2025)

Interpretable machine learning approach for electron antineutrino selection in a large liquid scintillator detector

Authors: A. Gavrikov, V. Cerrone, A. Serafini, R. Brugnera, A. Garfagnini, M. Grassi, B. Jelmini, L. Lastrucci, S. Aiello, G. Andronico, V. Antonelli, A. Barresi, D. Basilico, M. Beretta, A. Bergnoli, M. Borghesi, A. Brigatti, R. Bruno, A. Budano, B. Caccianiga, A. Cammi, R. Caruso, D. Chiesa, C. Clementi, S. Dusini , et al. (43 additional authors not shown)

Abstract: Several neutrino detectors, KamLAND, Daya Bay, Double Chooz, RENO, and the forthcoming large-scale JUNO, rely on liquid scintillator to detect reactor antineutrino interactions. In this context, inverse beta decay represents the golden channel for antineutrino detection, providing a pair of correlated events, thus a strong experimental signature to distinguish the signal from a variety of backgrou… ▽ More Several neutrino detectors, KamLAND, Daya Bay, Double Chooz, RENO, and the forthcoming large-scale JUNO, rely on liquid scintillator to detect reactor antineutrino interactions. In this context, inverse beta decay represents the golden channel for antineutrino detection, providing a pair of correlated events, thus a strong experimental signature to distinguish the signal from a variety of backgrounds. However, given the low cross-section of antineutrino interactions, the development of a powerful event selection algorithm becomes imperative to achieve effective discrimination between signal and backgrounds. In this study, we introduce a machine learning (ML) model to achieve this goal: a fully connected neural network as a powerful signal-background discriminator for a large liquid scintillator detector. We demonstrate, using the JUNO detector as an example, that, despite the already high efficiency of a cut-based approach, the presented ML model can further improve the overall event selection efficiency. Moreover, it allows for the retention of signal events at the detector edges that would otherwise be rejected because of the overwhelming amount of background events in that region. We also present the first interpretable analysis of the ML approach for event selection in reactor neutrino experiments. This method provides insights into the decision-making process of the model and offers valuable information for improving and updating traditional event selection approaches. △ Less

Submitted 25 November, 2024; v1 submitted 9 June, 2024; originally announced June 2024.

Comments: This is a post-peer-review, pre-copyedit version of an article published in Phys. Lett. B. The final published version is available online: https://www.sciencedirect.com/science/article/pii/S0370269324006993

Journal ref: Physics Letters B 860, 139141 (2025)

Search for fractionally charged particles with CUORE

Authors: CUORE Collaboration, D. Q. Adams, C. Alduino, K. Alfonso, F. T. Avignone III, O. Azzolini, G. Bari, F. Bellini, G. Benato, M. Beretta, M. Biassoni, A. Branca, C. Brofferio, C. Bucci, J. Camilleri, A. Caminata, A. Campani, J. Cao, S. Capelli, C. Capelli, L. Cappelli, L. Cardani, P. Carniti, N. Casali, E. Celi , et al. (95 additional authors not shown)

Abstract: The Cryogenic Underground Observatory for Rare Events (CUORE) is a detector array comprised by 988 5$\;$cm$\times$5$\;$cm$\times$5$\;$cm TeO$_2$ crystals held below 20 mK, primarily searching for neutrinoless double-beta decay in $^{130}$Te. Unprecedented in size amongst cryogenic calorimetric experiments, CUORE provides a promising setting for the study of exotic through-going particles. Using th… ▽ More The Cryogenic Underground Observatory for Rare Events (CUORE) is a detector array comprised by 988 5$\;$cm$\times$5$\;$cm$\times$5$\;$cm TeO$_2$ crystals held below 20 mK, primarily searching for neutrinoless double-beta decay in $^{130}$Te. Unprecedented in size amongst cryogenic calorimetric experiments, CUORE provides a promising setting for the study of exotic through-going particles. Using the first tonne-year of CUORE's exposure, we perform a search for hypothesized fractionally charged particles (FCPs), which are well-motivated by various Standard Model extensions and would have suppressed interactions with matter. No excess of FCP candidate tracks is observed over background, setting leading limits on the underground FCP flux with charges between $e/24-e/5$ at 90\% confidence level. Using the low background environment and segmented geometry of CUORE, we establish the sensitivity of tonne-scale sub-Kelvin detectors to diverse signatures of new physics. △ Less

Submitted 18 June, 2024; originally announced June 2024.

Comments: 7 pages, 5 figures

Distillation and Stripping purification plants for JUNO liquid scintillator

Authors: C. Landini, M. Beretta, P. Lombardi, A. Brigatti, M. Montuschi, S. Parmeggiano, G. Ranucci, V. Antonelli, D. Basilico, B. Caccianiga, M. G. Giammarchi, L. Miramonti, E. Percalli, A. C. Re, P. Saggese, M. D. C. Torri, S. Aiello, G. Andronico, A. Barresi, A. Bergnoli, M. Borghesi, R. Brugnera, R. Bruno, A. Budano, A. Cammi , et al. (42 additional authors not shown)

Abstract: The optical and radiochemical purification of the scintillating liquid, which will fill the central detector of the JUNO experiment, plays a crucial role in achieving its scientific goals. Given its gigantic mass and dimensions and an unprecedented target value of about 3% @ 1 MeV in energy resolution, JUNO has set severe requirements on the parameters of its scintillator, such as attenuation leng… ▽ More The optical and radiochemical purification of the scintillating liquid, which will fill the central detector of the JUNO experiment, plays a crucial role in achieving its scientific goals. Given its gigantic mass and dimensions and an unprecedented target value of about 3% @ 1 MeV in energy resolution, JUNO has set severe requirements on the parameters of its scintillator, such as attenuation length (Lat>20 m at 430 nm), transparency, light yield, and content of radioactive contaminants (238U,232Th<10-15 g/g). To accomplish these needs, the scintillator will be processed using several purification methods, including distillation in partial vacuum and gas stripping, which are performed in two large scale plants installed at the JUNO site. In this paper, layout, operating principles, and technical aspects which have driven the design and construction of the distil- lation and gas stripping plants are reviewed. The distillation is effective in enhancing the optical properties and removing heavy radio-impurities (238U,232Th, 40K), while the stripping process exploits pure water steam and high-purity nitrogen to extract gaseous contaminants (222Rn, 39Ar, 85Kr, O2) from the scintillator. The plant operating parameters have been tuned during the recent com- missioning phase at the JUNO site and several QA/QC measurements and tests have been performed to evaluate the performances of the plants. Some preliminary results on the efficiency of these purification processes will be shown. △ Less

Submitted 3 June, 2024; originally announced June 2024.

Comments: 11 pages, 7 figures

Refractive index in the JUNO liquid scintillator

Authors: H. S. Zhang, M. Beretta, S. Cialdi, C. X. Yang, J. H. Huang, F. Ferraro, G. F. Cao, G. Reina, Z. Y. Deng, E. Suerra, S. Altilia, V. Antonelli, D. Basilico, A. Brigatti, B. Caccianiga, M. G. Giammarchi, C. Landini, P. Lombardi, L. Miramonti, E. Percalli, G. Ranucci, A. C. Re, P. Saggese, M. D. C. Torri, S. Aiello , et al. (51 additional authors not shown)

Abstract: In the field of rare event physics, it is common to have huge masses of organic liquid scintillator as detection medium. In particular, they are widely used to study neutrino properties or astrophysical neutrinos. Thanks to its safety properties (such as low toxicity and high flash point) and easy scalability, linear alkyl benzene is the most common solvent used to produce liquid scintillators for… ▽ More In the field of rare event physics, it is common to have huge masses of organic liquid scintillator as detection medium. In particular, they are widely used to study neutrino properties or astrophysical neutrinos. Thanks to its safety properties (such as low toxicity and high flash point) and easy scalability, linear alkyl benzene is the most common solvent used to produce liquid scintillators for large mass experiments. The knowledge of the refractive index is a pivotal point to understand the detector response, as this quantity (and its wavelength dependence) affects the Cherenkov radiation and photon propagation in the medium. In this paper, we report the measurement of the refractive index of the JUNO liquid scintillator between 260-1064 nm performed with two different methods (an ellipsometer and a refractometer), with a sub percent level precision. In addition, we used an interferometer to measure the group velocity in the JUNO liquid scintillator and verify the expected value derived from the refractive index measurements. △ Less

Submitted 30 May, 2024; originally announced May 2024.

Comments: 6 pages, 9 figures

Data-driven background model for the CUORE experiment

Authors: CUORE Collaboration, D. Q. Adams, C. Alduino, K. Alfonso, F. T. Avignone III, O. Azzolini, G. Bari, F. Bellini, G. Benato, M. Beretta, M. Biassoni, A. Branca, C. Brofferio, C. Bucci, J. Camilleri, A. Caminata, A. Campani, J. Cao, S. Capelli, C. Capelli, L. Cappelli, L. Cardani, P. Carniti, N. Casali, E. Celi , et al. (93 additional authors not shown)

Abstract: We present the model we developed to reconstruct the CUORE radioactive background based on the analysis of an experimental exposure of 1038.4 kg yr. The data reconstruction relies on a simultaneous Bayesian fit applied to energy spectra over a broad energy range. The high granularity of the CUORE detector, together with the large exposure and extended stable operations, allow for an in-depth explo… ▽ More We present the model we developed to reconstruct the CUORE radioactive background based on the analysis of an experimental exposure of 1038.4 kg yr. The data reconstruction relies on a simultaneous Bayesian fit applied to energy spectra over a broad energy range. The high granularity of the CUORE detector, together with the large exposure and extended stable operations, allow for an in-depth exploration of both spatial and time dependence of backgrounds. We achieve high sensitivity to both bulk and surface activities of the materials of the setup, detecting levels as low as 10 nBq kg$^{-1}$ and 0.1 nBq cm$^{-2}$, respectively. We compare the contamination levels we extract from the background model with prior radio-assay data, which informs future background risk mitigation strategies. The results of this background model play a crucial role in constructing the background budget for the CUPID experiment as it will exploit the same CUORE infrastructure. △ Less

Submitted 28 May, 2024; originally announced May 2024.

Prediction of Energy Resolution in the JUNO Experiment

Authors: JUNO Collaboration, Angel Abusleme, Thomas Adam, Kai Adamowicz, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, João Pedro Athayde Marcondes de André, Didier Auguste, Weidong Bai, Nikita Balashov, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Marco Beretta, Antonio Bergnoli, Daniel Bick , et al. (629 additional authors not shown)

Abstract: This paper presents an energy resolution study of the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3\% at 1~MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components o… ▽ More This paper presents an energy resolution study of the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3\% at 1~MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of the liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The results of study reveal an energy resolution of 2.95\% at 1~MeV. Furthermore, this study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data collection. Moreover, it provides a guideline for comprehending the energy resolution characteristics of liquid scintillator-based detectors. △ Less

Submitted 9 January, 2025; v1 submitted 28 May, 2024; originally announced May 2024.

Journal ref: Chinese Phys. C 49 013003 (2025)

Analysis of reactor burnup simulation uncertainties for antineutrino spectrum prediction

Authors: A. Barresi, M. Borghesi, A. Cammi, D. Chiesa, L. Loi, M. Nastasi, E. Previtali, M. Sisti, S. Aiello, G. Andronico, V. Antonelli, D. Basilico, M. Beretta, A. Bergnoli, A. Brigatti, R. Brugnera, R. Bruno, A. Budano, B. Caccianiga, V. Cerrone, R. Caruso, C. Clementi, S. Dusini, A. Fabbri, G. Felici , et al. (42 additional authors not shown)

Abstract: Nuclear reactors are a source of electron antineutrinos due to the presence of unstable fission products that undergo $β^-$ decay. They will be exploited by the JUNO experiment to determine the neutrino mass ordering and to get very precise measurements of the neutrino oscillation parameters. This requires the reactor antineutrino spectrum to be characterized as precisely as possible both through… ▽ More Nuclear reactors are a source of electron antineutrinos due to the presence of unstable fission products that undergo $β^-$ decay. They will be exploited by the JUNO experiment to determine the neutrino mass ordering and to get very precise measurements of the neutrino oscillation parameters. This requires the reactor antineutrino spectrum to be characterized as precisely as possible both through high resolution measurements, as foreseen by the TAO experiment, and detailed simulation models. In this paper we present a benchmark analysis utilizing Serpent Monte Carlo simulations in comparison with real pressurized water reactor spent fuel data. Our objective is to study the accuracy of fission fraction predictions as a function of different reactor simulation approximations. Then, utilizing the BetaShape software, we construct fissile antineutrino spectra using the summation method, thereby assessing the influence of simulation uncertainties on reactor antineutrino spectrum. △ Less

Submitted 30 October, 2024; v1 submitted 21 November, 2023; originally announced November 2023.

Journal ref: Eur. Phys. J. Plus 139, 952 (2024)

Environmental radon control in the 700-m underground laboratory at JUNO

Authors: Chenyang Cui, Jie Zhao, Gaosong Li, Yongpeng Zhang, Cong Guo, Zhenning Qu, Yifang Wang, Xiaonan Li, Liangjian Wen, Miao He, Monica Sisti

Abstract: The Jiangmen Underground Neutrino Observatory is building the world's largest liquid scintillator detector with a 20 kt target mass and about 700 m overburden. The total underground space of civil construction is about 300,000 m$^3$ with the main hall volume of about 120,000 m$^3$, which is the biggest laboratory in the world. Radon concentration in the underground air is quite important for not o… ▽ More The Jiangmen Underground Neutrino Observatory is building the world's largest liquid scintillator detector with a 20 kt target mass and about 700 m overburden. The total underground space of civil construction is about 300,000 m$^3$ with the main hall volume of about 120,000 m$^3$, which is the biggest laboratory in the world. Radon concentration in the underground air is quite important for not only human beings' health but also the background of experiments with rare decay detection, such as neutrino and dark matter experiments. The radon concentration is the main hall is required to be around 100 Bq/m$^3$. Optimization of the ventilation with fresh air is effective to control the radon underground. To find the radon sources in the underground laboratory, we made a benchmark experiment in the refuge room near the main hall. The result shows that the radon emanating from underground water is one of the main radon sources in the underground air. The total underground ventilation rate is about 160,000 m$^3$/h fresh air with about 30 Bq/m$^3$ $^{222}$Rn from the bottom of the vertical tunnel after optimization, and 55,000 m$^3$/h is used for the ventilation in the main hall. Finally, the radon concentration inside the main hall decreased from 1600 Bq/m$^3$ to around 100 Bq/m$^3$. The suggested strategies for controlling radon concentration in the underground air are described in this paper. △ Less

Submitted 12 September, 2023; originally announced September 2023.

Journal ref: Eur. Phys. J. C (2024) 84:120

Array of Cryogenic Calorimeters to Evaluate the Spectral Shape of forbidden $β$-decays: the ACCESS project

Authors: L. Pagnanini, G. Benato, P. Carniti, E. Celi, D. Chiesa, J. Corbett, I. Dafinei, S. Di Domizio, P. Di Stefano, S. Ghislandi, C. Gotti, D. L. Helis, R. Knobel, J. Kostensalo, J. Kotila, S. Nagorny, G. Pessina, S. Pirro, S. Pozzi, A. Puiu, S. Quitadamo, M. Sisti, J. Suhonen, S. Kuznetsov

Abstract: The ACCESS (Array of Cryogenic Calorimeters to Evaluate Spectral Shapes) project aims to establish a novel technique to perform precision measurements of forbidden \b{eta}-decays, which can serve as an important benchmark for nuclear physics calculations and represent a significant background in astroparticle physics experiments. ACCESS will operate a pilot array of cryogenic calorimeters based on… ▽ More The ACCESS (Array of Cryogenic Calorimeters to Evaluate Spectral Shapes) project aims to establish a novel technique to perform precision measurements of forbidden \b{eta}-decays, which can serve as an important benchmark for nuclear physics calculations and represent a significant background in astroparticle physics experiments. ACCESS will operate a pilot array of cryogenic calorimeters based on natural and doped crystals containing \b{eta}-emitting radionuclides. In this way, natural (e.g. 113 Cd and 115In) and synthetic isotopes (e.g. 99Tc) will be simultaneously measured with a common experimental technique. The array will also include further crystals optimised to disentangle the different background sources, thus reducing the systematic uncertainty. In this paper, we give an overview of the ACCESS research program, discussing a detector design study and promising results of 115In. △ Less

Submitted 3 May, 2023; originally announced May 2023.

Comments: 12 pages, 12 figures

Journal ref: Eur. Phys. J. Plus 138, 445 (2023)

A first test of CUPID prototypal light detectors with NTD-Ge sensors in a pulse-tube cryostat

Authors: CUPID collaboration, K. Alfonso, A. Armatol, C. Augier, F. T. Avignone III, O. Azzolini, M. Balata, A. S. Barabash, G. Bari, A. Barresi, D. Baudin, F. Bellini, G. Benato, V. Berest, M. Beretta, M. Bettelli, M. Biassoni, J. Billard, V. Boldrini, A. Branca, C. Brofferio, C. Bucci, J. Camilleri, A. Campani, C. Capelli , et al. (154 additional authors not shown)

Abstract: CUPID is a next-generation bolometric experiment aiming at searching for neutrinoless double-beta decay with ~250 kg of isotopic mass of $^{100}$Mo. It will operate at $\sim$10 mK in a cryostat currently hosting a similar-scale bolometric array for the CUORE experiment at the Gran Sasso National Laboratory (Italy). CUPID will be based on large-volume scintillating bolometers consisting of… ▽ More CUPID is a next-generation bolometric experiment aiming at searching for neutrinoless double-beta decay with ~250 kg of isotopic mass of $^{100}$Mo. It will operate at $\sim$10 mK in a cryostat currently hosting a similar-scale bolometric array for the CUORE experiment at the Gran Sasso National Laboratory (Italy). CUPID will be based on large-volume scintillating bolometers consisting of $^{100}$Mo-enriched Li$_2$MoO$_4$ crystals, facing thin Ge-wafer-based bolometric light detectors. In the CUPID design, the detector structure is novel and needs to be validated. In particular, the CUORE cryostat presents a high level of mechanical vibrations due to the use of pulse tubes and the effect of vibrations on the detector performance must be investigated. In this paper we report the first test of the CUPID-design bolometric light detectors with NTD-Ge sensors in a dilution refrigerator equipped with a pulse tube in an above-ground lab. Light detectors are characterized in terms of sensitivity, energy resolution, pulse time constants, and noise power spectrum. Despite the challenging noisy environment due to pulse-tube-induced vibrations, we demonstrate that all the four tested light detectors comply with the CUPID goal in terms of intrinsic energy resolution of 100 eV RMS baseline noise. Indeed, we have measured 70--90 eV RMS for the four devices, which show an excellent reproducibility. We have also obtained outstanding energy resolutions at the 356 keV line from a $^{133}$Ba source with one light detector achieving 0.71(5) keV FWHM, which is -- to our knowledge -- the best ever obtained when compared to $γ$ detectors of any technology in this energy range. △ Less

Submitted 10 April, 2023; originally announced April 2023.

Comments: Prepared for submission to JINST; 16 pages, 7 figures, and 1 table

Twelve-crystal prototype of Li$_2$MoO$_4$ scintillating bolometers for CUPID and CROSS experiments

Authors: CUPID, CROSS collaborations, :, K. Alfonso, A. Armatol, C. Augier, F. T. Avignone III, O. Azzolini, M. Balata, I. C. Bandac, A. S. Barabash, G. Bari, A. Barresi, D. Baudin, F. Bellini, G. Benato, V. Berest, M. Beretta, M. Bettelli, M. Biassoni, J. Billard, V. Boldrini, A. Branca, C. Brofferio, C. Bucci , et al. (160 additional authors not shown)

Abstract: An array of twelve 0.28 kg lithium molybdate (LMO) low-temperature bolometers equipped with 16 bolometric Ge light detectors, aiming at optimization of detector structure for CROSS and CUPID double-beta decay experiments, was constructed and tested in a low-background pulse-tube-based cryostat at the Canfranc underground laboratory in Spain. Performance of the scintillating bolometers was studied… ▽ More An array of twelve 0.28 kg lithium molybdate (LMO) low-temperature bolometers equipped with 16 bolometric Ge light detectors, aiming at optimization of detector structure for CROSS and CUPID double-beta decay experiments, was constructed and tested in a low-background pulse-tube-based cryostat at the Canfranc underground laboratory in Spain. Performance of the scintillating bolometers was studied depending on the size of phonon NTD-Ge sensors glued to both LMO and Ge absorbers, shape of the Ge light detectors (circular vs. square, from two suppliers), in different light collection conditions (with and without reflector, with aluminum coated LMO crystal surface). The scintillating bolometer array was operated over 8 months in the low-background conditions that allowed to probe a very low, $μ$Bq/kg, level of the LMO crystals radioactive contamination by $^{228}$Th and $^{226}$Ra. △ Less

Submitted 10 April, 2023; originally announced April 2023.

Comments: Prepared for submission to JINST; 23 pages, 9 figures, and 4 tables

The JUNO experiment Top Tracker

Authors: JUNO Collaboration, Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Abid Aleem, Tsagkarakis Alexandros, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Weidong Bai, Nikita Balashov, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato , et al. (592 additional authors not shown)

Abstract: The main task of the Top Tracker detector of the neutrino reactor experiment Jiangmen Underground Neutrino Observatory (JUNO) is to reconstruct and extrapolate atmospheric muon tracks down to the central detector. This muon tracker will help to evaluate the contribution of the cosmogenic background to the signal. The Top Tracker is located above JUNO's water Cherenkov Detector and Central Detector… ▽ More The main task of the Top Tracker detector of the neutrino reactor experiment Jiangmen Underground Neutrino Observatory (JUNO) is to reconstruct and extrapolate atmospheric muon tracks down to the central detector. This muon tracker will help to evaluate the contribution of the cosmogenic background to the signal. The Top Tracker is located above JUNO's water Cherenkov Detector and Central Detector, covering about 60% of the surface above them. The JUNO Top Tracker is constituted by the decommissioned OPERA experiment Target Tracker modules. The technology used consists in walls of two planes of plastic scintillator strips, one per transverse direction. Wavelength shifting fibres collect the light signal emitted by the scintillator strips and guide it to both ends where it is read by multianode photomultiplier tubes. Compared to the OPERA Target Tracker, the JUNO Top Tracker uses new electronics able to cope with the high rate produced by the high rock radioactivity compared to the one in Gran Sasso underground laboratory. This paper will present the new electronics and mechanical structure developed for the Top Tracker of JUNO along with its expected performance based on the current detector simulation. △ Less

Submitted 9 March, 2023; originally announced March 2023.

Comments: 20 pages

Journal ref: Nucl.Instrum.Meth.A 1057 (2023) 168680

JUNO sensitivity to $^7$Be, $pep$, and CNO solar neutrinos

Authors: Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Abid Aleem, Tsagkarakis Alexandros, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Weidong Bai, Nikita Balashov, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Marco Beretta , et al. (592 additional authors not shown)

Abstract: The Jiangmen Underground Neutrino Observatory (JUNO), the first multi-kton liquid scintillator detector, which is under construction in China, will have a unique potential to perform a real-time measurement of solar neutrinos well below the few MeV threshold typical for Water Cherenkov detectors. JUNO's large target mass and excellent energy resolution are prerequisites for reaching unprecedented… ▽ More The Jiangmen Underground Neutrino Observatory (JUNO), the first multi-kton liquid scintillator detector, which is under construction in China, will have a unique potential to perform a real-time measurement of solar neutrinos well below the few MeV threshold typical for Water Cherenkov detectors. JUNO's large target mass and excellent energy resolution are prerequisites for reaching unprecedented levels of precision. In this paper, we provide estimation of the JUNO sensitivity to 7Be, pep, and CNO solar neutrinos that can be obtained via a spectral analysis above the 0.45 MeV threshold. This study is performed assuming different scenarios of the liquid scintillator radiopurity, ranging from the most opti mistic one corresponding to the radiopurity levels obtained by the Borexino experiment, up to the minimum requirements needed to perform the neutrino mass ordering determination with reactor antineutrinos - the main goal of JUNO. Our study shows that in most scenarios, JUNO will be able to improve the current best measurements on 7Be, pep, and CNO solar neutrino fluxes. We also perform a study on the JUNO capability to detect periodical time variations in the solar neutrino flux, such as the day-night modulation induced by neutrino flavor regeneration in Earth, and the modulations induced by temperature changes driven by helioseismic waves. △ Less

Submitted 7 March, 2023; originally announced March 2023.

Implementation and performances of the IPbus protocol for the JUNO Large-PMT readout electronics

Authors: Riccardo Triozzi, Andrea Serafini, Marco Bellato, Antonio Bergnoli, Matteo Bolognesi, Riccardo Brugnera, Vanessa Cerrone, Chao Chen, Barbara Clerbaux, Alberto Coppi, Daniele Corti, Flavio dal Corso, Jianmeng Dong, Wei Dou, Lei Fan, Alberto Garfagnini, Arsenii Gavrikov, Guanghua Gong, Marco Grassi, Rosa Maria Guizzetti, Shuang Hang, Cong He, Jun Hu, Roberto Isocrate, Beatrice Jelmini , et al. (107 additional authors not shown)

Abstract: The Jiangmen Underground Neutrino Observatory (JUNO) is a large neutrino detector currently under construction in China. Thanks to the tight requirements on its optical and radio-purity properties, it will be able to perform leading measurements detecting terrestrial and astrophysical neutrinos in a wide energy range from tens of keV to hundreds of MeV. A key requirement for the success of the exp… ▽ More The Jiangmen Underground Neutrino Observatory (JUNO) is a large neutrino detector currently under construction in China. Thanks to the tight requirements on its optical and radio-purity properties, it will be able to perform leading measurements detecting terrestrial and astrophysical neutrinos in a wide energy range from tens of keV to hundreds of MeV. A key requirement for the success of the experiment is an unprecedented 3% energy resolution, guaranteed by its large active mass (20 kton) and the use of more than 20,000 20-inch photo-multiplier tubes (PMTs) acquired by high-speed, high-resolution sampling electronics located very close to the PMTs. As the Front-End and Read-Out electronics is expected to continuously run underwater for 30 years, a reliable readout acquisition system capable of handling the timestamped data stream coming from the Large-PMTs and permitting to simultaneously monitor and operate remotely the inaccessible electronics had to be developed. In this contribution, the firmware and hardware implementation of the IPbus based readout protocol will be presented, together with the performances measured on final modules during the mass production of the electronics. △ Less

Submitted 20 February, 2023; originally announced February 2023.

Study on U/Th residual radioactivity in acrylic from surface treatment

Authors: Yuanxia Li, Xiaohui Qian, Xiaolan Luo, Jie Zhao, Gaofeng Zhang, Xiaoyan Ma, Yuekun Heng, Liangjian Wen, Monica Sisti, Frédéric Perrot, Hongqiang Tang

Abstract: Acrylic is widely used as material for the target container in low background experiments due to its high light transparency and low intrinsic radioactivity. However, its surface can be easily contaminated during production, so careful treatment of the surface is essential to avoid direct contamination of the target. The Jiangmen Underground Neutrino Observatory will use about 600~t of acrylic to… ▽ More Acrylic is widely used as material for the target container in low background experiments due to its high light transparency and low intrinsic radioactivity. However, its surface can be easily contaminated during production, so careful treatment of the surface is essential to avoid direct contamination of the target. The Jiangmen Underground Neutrino Observatory will use about 600~t of acrylic to build the spherical vessel of 35.4~m in diameter for a 20~kt liquid scintillator (LS). Since acrylic will contact the LS directly, the cleanliness of the its surface is quite important for the radiopurity of the LS. A new method for measuring the radioactivity of $^{238}$U and $^{232}$Th in acrylic to sub-ppt ($<10^{-12}$~g/g) was developed, and it is crucial for the acrylic radioactivity screening in this study. We performed many background tests on different surface treatments, and the recommended procedure for the treatment of acrylic to achieve low radioactivity and high light transparency could be applicable to other low background experiments. △ Less

Submitted 12 January, 2023; originally announced January 2023.

Mass testing of the JUNO experiment 20-inch PMTs readout electronics

Authors: Alberto Coppi, Beatrice Jelmini, Marco Bellato, Antonio Bergnoli, Matteo Bolognesi, Riccardo Brugnera, Vanessa Cerrone, Chao Chen, Barbara Clerbaux, Daniele Corti, Flavio dal Corso, Jianmeng Dong, Wei Dou, Lei Fan, Alberto Garfagnini, Arsenii Gavrikov, Guanghua Gong, Marco Grassi, Rosa Maria Guizzetti, Shuang Hang, Cong He, Jun Hu, Roberto Isocrate, Xiaolu Ji, Xiaoshan Jiang , et al. (107 additional authors not shown)

Abstract: The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose, large size, liquid scintillator experiment under construction in China. JUNO will perform leading measurements detecting neutrinos from different sources (reactor, terrestrial and astrophysical neutrinos) covering a wide energy range (from 200 keV to several GeV). This paper focuses on the design and development of a test pro… ▽ More The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose, large size, liquid scintillator experiment under construction in China. JUNO will perform leading measurements detecting neutrinos from different sources (reactor, terrestrial and astrophysical neutrinos) covering a wide energy range (from 200 keV to several GeV). This paper focuses on the design and development of a test protocol for the 20-inch PMT underwater readout electronics, performed in parallel to the mass production line. In a time period of about ten months, a total number of 6950 electronic boards were tested with an acceptance yield of 99.1%. △ Less

Submitted 11 January, 2023; originally announced January 2023.

Validation and integration tests of the JUNO 20-inch PMTs readout electronics

Authors: Vanessa Cerrone, Katharina von Sturm, Marco Bellato, Antonio Bergnoli, Matteo Bolognesi, Riccardo Brugnera, Chao Chen, Barbara Clerbaux, Alberto Coppi, Flavio dal Corso, Daniele Corti, Jianmeng Dong, Wei Dou, Lei Fan, Alberto Garfagnini, Guanghua Gong, Marco Grassi, Shuang Hang, Rosa Maria Guizzetti, Cong He, Jun Hu, Roberto Isocrate, Beatrice Jelmini, Xiaolu Ji, Xiaoshan Jiang , et al. (105 additional authors not shown)

Abstract: The Jiangmen Underground Neutrino Observatory (JUNO) is a large neutrino detector currently under construction in China. JUNO will be able to study the neutrino mass ordering and to perform leading measurements detecting terrestrial and astrophysical neutrinos in a wide energy range, spanning from 200 keV to several GeV. Given the ambitious physics goals of JUNO, the electronic system has to meet… ▽ More The Jiangmen Underground Neutrino Observatory (JUNO) is a large neutrino detector currently under construction in China. JUNO will be able to study the neutrino mass ordering and to perform leading measurements detecting terrestrial and astrophysical neutrinos in a wide energy range, spanning from 200 keV to several GeV. Given the ambitious physics goals of JUNO, the electronic system has to meet specific tight requirements, and a thorough characterization is required. The present paper describes the tests performed on the readout modules to measure their performances. △ Less

Submitted 16 December, 2022; originally announced December 2022.

Comments: 20 pages, 13 figures

Disentangling the sources of ionizing radiation in superconducting qubits

Authors: L. Cardani, I. Colantoni, A. Cruciani, F. De Dominicis, G. D'Imperio, M. Laubenstein, A. Mariani, L. Pagnanini, S. Pirro, C. Tomei, N. Casali, F. Ferroni, D. Frolov, L. Gironi, A. Grassellino, M. Junker, C. Kopas, E. Lachman, C. R. H. McRae, J. Mutus, M. Nastasi, D. P. Pappas, R. Pilipenko, M. Sisti, V. Pettinacci , et al. (5 additional authors not shown)

Abstract: Radioactivity was recently discovered as a source of decoherence and correlated errors for the real-world implementation of superconducting quantum processors. In this work, we measure levels of radioactivity present in a typical laboratory environment (from muons, neutrons, and gamma's emitted by naturally occurring radioactive isotopes) and in the most commonly used materials for the assembly an… ▽ More Radioactivity was recently discovered as a source of decoherence and correlated errors for the real-world implementation of superconducting quantum processors. In this work, we measure levels of radioactivity present in a typical laboratory environment (from muons, neutrons, and gamma's emitted by naturally occurring radioactive isotopes) and in the most commonly used materials for the assembly and operation of state-of-the-art superconducting qubits. We develop a GEANT-4 based simulation to predict the rate of impacts and the amount of energy released in a qubit chip from each of the mentioned sources. We finally propose mitigation strategies for the operation of next-generation qubits in a radio-pure environment. △ Less

Submitted 24 November, 2022; originally announced November 2022.

Production of monochromatic $^{228}$Ra $α$-sources for detector characterization

Authors: M. Biassoni, C. Brofferio, S. Dell'Oro, L. Gironi, M. Nastasi, M. Sisti

Abstract: The response of particle detectors to different types of radiation is not necessarily identical and, in some cases, neglecting this behavior can lead to a misinterpretation of the acquired data. While commercial radioactive sources are in general suitable to investigate the response to $β$'s and $γ$'s, in the case of $α$'s the need for custom-made sources arises from the intrinsic properties of… ▽ More The response of particle detectors to different types of radiation is not necessarily identical and, in some cases, neglecting this behavior can lead to a misinterpretation of the acquired data. While commercial radioactive sources are in general suitable to investigate the response to $β$'s and $γ$'s, in the case of $α$'s the need for custom-made sources arises from the intrinsic properties of $α$ radiation, which imposes that the emitter directly faces the detector. In this work, we show how to flexibly produce $α$ sources to be employed in multiple studies of detector characterization. These are obtained starting from a set of primary sources obtained from the collection of radioactive $^{228}$Ra ions at the ISOLDE facility at CERN. We illustrate the potential of this technique with practical cases of application to scintillators and bolometric detectors and examples of the results obtained so far. △ Less

Submitted 6 December, 2022; v1 submitted 30 May, 2022; originally announced May 2022.

Journal ref: Eur. Phys. J. Plus 137, 1309 (2022)

Prospects for Detecting the Diffuse Supernova Neutrino Background with JUNO

Authors: JUNO Collaboration, Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Nikita Balashov, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Antonio Bergnoli, Thilo Birkenfeld, Sylvie Blin , et al. (577 additional authors not shown)

Abstract: We present the detection potential for the diffuse supernova neutrino background (DSNB) at the Jiangmen Underground Neutrino Observatory (JUNO), using the inverse-beta-decay (IBD) detection channel on free protons. We employ the latest information on the DSNB flux predictions, and investigate in detail the background and its reduction for the DSNB search at JUNO. The atmospheric neutrino induced n… ▽ More We present the detection potential for the diffuse supernova neutrino background (DSNB) at the Jiangmen Underground Neutrino Observatory (JUNO), using the inverse-beta-decay (IBD) detection channel on free protons. We employ the latest information on the DSNB flux predictions, and investigate in detail the background and its reduction for the DSNB search at JUNO. The atmospheric neutrino induced neutral current (NC) background turns out to be the most critical background, whose uncertainty is carefully evaluated from both the spread of model predictions and an envisaged \textit{in situ} measurement. We also make a careful study on the background suppression with the pulse shape discrimination (PSD) and triple coincidence (TC) cuts. With latest DSNB signal predictions, more realistic background evaluation and PSD efficiency optimization, and additional TC cut, JUNO can reach the significance of 3$σ$ for 3 years of data taking, and achieve better than 5$σ$ after 10 years for a reference DSNB model. In the pessimistic scenario of non-observation, JUNO would strongly improve the limits and exclude a significant region of the model parameter space. △ Less

Submitted 13 October, 2022; v1 submitted 18 May, 2022; originally announced May 2022.

Comments: 29 pages, 11 figures, final published version in JCAP

Journal ref: JCAP 10 (2022) 033

Mass Testing and Characterization of 20-inch PMTs for JUNO

Authors: Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Abid Aleem, Tsagkarakis Alexandros, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, Joao Pedro Athayde Marcondes de Andre, Didier Auguste, Weidong Bai, Nikita Balashov, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Antonio Bergnoli , et al. (541 additional authors not shown)

Abstract: Main goal of the JUNO experiment is to determine the neutrino mass ordering using a 20kt liquid-scintillator detector. Its key feature is an excellent energy resolution of at least 3 % at 1 MeV, for which its instruments need to meet a certain quality and thus have to be fully characterized. More than 20,000 20-inch PMTs have been received and assessed by JUNO after a detailed testing program whic… ▽ More Main goal of the JUNO experiment is to determine the neutrino mass ordering using a 20kt liquid-scintillator detector. Its key feature is an excellent energy resolution of at least 3 % at 1 MeV, for which its instruments need to meet a certain quality and thus have to be fully characterized. More than 20,000 20-inch PMTs have been received and assessed by JUNO after a detailed testing program which began in 2017 and elapsed for about four years. Based on this mass characterization and a set of specific requirements, a good quality of all accepted PMTs could be ascertained. This paper presents the performed testing procedure with the designed testing systems as well as the statistical characteristics of all 20-inch PMTs intended to be used in the JUNO experiment, covering more than fifteen performance parameters including the photocathode uniformity. This constitutes the largest sample of 20-inch PMTs ever produced and studied in detail to date, i.e. 15,000 of the newly developed 20-inch MCP-PMTs from Northern Night Vision Technology Co. (NNVT) and 5,000 of dynode PMTs from Hamamatsu Photonics K. K.(HPK). △ Less

Submitted 17 September, 2022; v1 submitted 17 May, 2022; originally announced May 2022.

An Energy-dependent Electro-thermal Response Model of CUORE Cryogenic Calorimeter

Authors: CUORE Collaboration, D. Q. Adams, C. Alduino, K. Alfonso, F. T. Avignone III, O. Azzolini, G. Bari, F. Bellini, G. Benato, M. Beretta, M. Biassoni, A. Branca, C. Brofferio, C. Bucci, J. Camilleri, A. Caminata, A. Campani, L. Canonica, X. G. Cao, S. Capelli, C. Capelli, L. Cappelli, L. Cardani, P. Carniti, N. Casali , et al. (96 additional authors not shown)

Abstract: The Cryogenic Underground Observatory for Rare Events (CUORE) is the most sensitive experiment searching for neutrinoless double-beta decay ($0νββ$) in $^{130}\text{Te}$. CUORE uses a cryogenic array of 988 TeO$_2$ calorimeters operated at $\sim$10 mK with a total mass of 741 kg. To further increase the sensitivity, the detector response must be well understood. Here, we present a non-linear therm… ▽ More The Cryogenic Underground Observatory for Rare Events (CUORE) is the most sensitive experiment searching for neutrinoless double-beta decay ($0νββ$) in $^{130}\text{Te}$. CUORE uses a cryogenic array of 988 TeO$_2$ calorimeters operated at $\sim$10 mK with a total mass of 741 kg. To further increase the sensitivity, the detector response must be well understood. Here, we present a non-linear thermal model for the CUORE experiment on a detector-by-detector basis. We have examined both equilibrium and dynamic electro-thermal models of detectors by numerically fitting non-linear differential equations to the detector data of a subset of CUORE channels which are well characterized and representative of all channels. We demonstrate that the hot-electron effect and electric-field dependence of resistance in NTD-Ge thermistors alone are inadequate to describe our detectors' energy dependent pulse shapes. We introduce an empirical second-order correction factor in the exponential temperature dependence of the thermistor, which produces excellent agreement with energy-dependent pulse shape data up to 6 MeV. We also present a noise analysis using the fitted thermal parameters and show that the intrinsic thermal noise is negligible compared to the observed noise for our detectors. △ Less

Submitted 28 July, 2022; v1 submitted 9 May, 2022; originally announced May 2022.

Comments: 34 pages, 14 figures, 6 tables

Optimization of the first CUPID detector module

Authors: CUPID collaboration, A. Armatol, C. Augier, F. T. Avignone III, O. Azzolini, M. Balata, K. Ballen, A. S. Barabash, G. Bari, A. Barresi, D. Baudin, F. Bellini, G. Benato, M. Beretta, M. Bettelli, M. Biassoni, J. Billard, V. Boldrini, A. Branca, C. Brofferio, C. Bucci, J. Camilleri, C. Capelli, S. Capelli, L. Cappelli , et al. (153 additional authors not shown)

Abstract: CUPID will be a next generation experiment searching for the neutrinoless double $β$ decay, whose discovery would establish the Majorana nature of the neutrino. Based on the experience achieved with the CUORE experiment, presently taking data at LNGS, CUPID aims to reach a background free environment by means of scintillating Li$_{2}$$^{100}$MoO$_4$ crystals coupled to light detectors. Indeed, the… ▽ More CUPID will be a next generation experiment searching for the neutrinoless double $β$ decay, whose discovery would establish the Majorana nature of the neutrino. Based on the experience achieved with the CUORE experiment, presently taking data at LNGS, CUPID aims to reach a background free environment by means of scintillating Li$_{2}$$^{100}$MoO$_4$ crystals coupled to light detectors. Indeed, the simultaneous heat and light detection allows us to reject the dominant background of $α$ particles, as proven by the CUPID-0 and CUPID-Mo demonstrators. In this work we present the results of the first test of the CUPID baseline module. In particular, we propose a new optimized detector structure and light sensors design to enhance the engineering and the light collection, respectively. We characterized the heat detectors, achieving an energy resolution of (5.9 $\pm$ 0.2) keV FWHM at the $Q$-value of $^{100}$Mo (about 3034 keV). We studied the light collection of the baseline CUPID design with respect to an alternative configuration which features gravity-assisted light detectors' mounting. In both cases we obtained an improvement in the light collection with respect to past measures and we validated the particle identification capability of the detector, which ensures an $α$ particle rejection higher than 99.9%, fully satisfying the requirements for CUPID. △ Less

Submitted 13 February, 2022; originally announced February 2022.

Comments: 10 pages, 5 figures

CUORE Opens the Door to Tonne-scale Cryogenics Experiments

Authors: CUORE Collaboration, D. Q. Adams, C. Alduino, F. Alessandria, K. Alfonso, E. Andreotti, F. T. Avignone III, O. Azzolini, M. Balata, I. Bandac, T. I. Banks, G. Bari, M. Barucci, J. W. Beeman, F. Bellini, G. Benato, M. Beretta, A. Bersani, D. Biare, M. Biassoni, F. Bragazzi, A. Branca, C. Brofferio, A. Bryant, A. Buccheri , et al. (184 additional authors not shown)

Abstract: The past few decades have seen major developments in the design and operation of cryogenic particle detectors. This technology offers an extremely good energy resolution - comparable to semiconductor detectors - and a wide choice of target materials, making low temperature calorimetric detectors ideal for a variety of particle physics applications. Rare event searches have continued to require eve… ▽ More The past few decades have seen major developments in the design and operation of cryogenic particle detectors. This technology offers an extremely good energy resolution - comparable to semiconductor detectors - and a wide choice of target materials, making low temperature calorimetric detectors ideal for a variety of particle physics applications. Rare event searches have continued to require ever greater exposures, which has driven them to ever larger cryogenic detectors, with the CUORE experiment being the first to reach a tonne-scale, mK-cooled, experimental mass. CUORE, designed to search for neutrinoless double beta decay, has been operational since 2017 at a temperature of about 10 mK. This result has been attained by the use of an unprecedentedly large cryogenic infrastructure called the CUORE cryostat: conceived, designed and commissioned for this purpose. In this article the main characteristics and features of the cryogenic facility developed for the CUORE experiment are highlighted. A brief introduction of the evolution of the field and of the past cryogenic facilities are given. The motivation behind the design and development of the CUORE cryogenic facility is detailed as are the steps taken toward realization, commissioning, and operation of the CUORE cryostat. The major challenges overcome by the collaboration and the solutions implemented throughout the building of the cryogenic facility will be discussed along with the potential improvements for future facilities. The success of CUORE has opened the door to a new generation of large-scale cryogenic facilities in numerous fields of science. Broader implications of the incredible feat achieved by the CUORE collaboration on the future cryogenic facilities in various fields ranging from neutrino and dark matter experiments to quantum computing will be examined. △ Less

Submitted 2 December, 2021; v1 submitted 17 August, 2021; originally announced August 2021.

Comments: 45 pages, 14 figures

Journal ref: Prog. Part. Nucl. Phys., 122 (2021), Article 103902

Characterizing current structures in 3D hybrid-kinetic simulations of plasma turbulence

Authors: Manuela Sisti, Sid Fadanelli, Silvio Sergio Cerri, Matteo Faganello, Francesco Califano, Olivier Agullo

Abstract: In space and astrophysical plasmas turbulence leads to the development of coherent structures characterized by a strong current density and important magnetic shears. Using hybrid-kinetic simulations of turbulence (3D with different energy injection scales) we investigate the development of these coherent structures and characterize their shape. First, we present different methods to estimate the… ▽ More In space and astrophysical plasmas turbulence leads to the development of coherent structures characterized by a strong current density and important magnetic shears. Using hybrid-kinetic simulations of turbulence (3D with different energy injection scales) we investigate the development of these coherent structures and characterize their shape. First, we present different methods to estimate the overall shape of the 3D structure using local measurements, foreseeing application on satellite data. Then we study the local magnetic configuration inside and outside current peak regions, comparing the statistics in the two cases. Last, we compare the statistical properties of the local configuration obtained in simulations with the ones obtained analyzing an MMS dataset having similar plasma parameters. Thanks to our analysis, 1) we validate the possibility to study the overall shape of 3D structures using local methods, 2) we provide an overview of local magnetic configuration emerging in different turbulent regimes, 3) we show that our 3D-3V simulations can reproduce the structures that emerge in MMS data for the periods studied by Phan et al. (2018), Stawarz et al. (2019). △ Less

Submitted 28 October, 2021; v1 submitted 29 July, 2021; originally announced July 2021.

Journal ref: A&A 655, A107 (2021)

Radioactivity control strategy for the JUNO detector

Authors: JUNO collaboration, Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Andrej Babic, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Antonio Bergnoli, Thilo Birkenfeld, Sylvie Blin , et al. (578 additional authors not shown)

Abstract: JUNO is a massive liquid scintillator detector with a primary scientific goal of determining the neutrino mass ordering by studying the oscillated anti-neutrino flux coming from two nuclear power plants at 53 km distance. The expected signal anti-neutrino interaction rate is only 60 counts per day, therefore a careful control of the background sources due to radioactivity is critical. In particula… ▽ More JUNO is a massive liquid scintillator detector with a primary scientific goal of determining the neutrino mass ordering by studying the oscillated anti-neutrino flux coming from two nuclear power plants at 53 km distance. The expected signal anti-neutrino interaction rate is only 60 counts per day, therefore a careful control of the background sources due to radioactivity is critical. In particular, natural radioactivity present in all materials and in the environment represents a serious issue that could impair the sensitivity of the experiment if appropriate countermeasures were not foreseen. In this paper we discuss the background reduction strategies undertaken by the JUNO collaboration to reduce at minimum the impact of natural radioactivity. We describe our efforts for an optimized experimental design, a careful material screening and accurate detector production handling, and a constant control of the expected results through a meticulous Monte Carlo simulation program. We show that all these actions should allow us to keep the background count rate safely below the target value of 10 Hz in the default fiducial volume, above an energy threshold of 0.7 MeV. △ Less

Submitted 13 October, 2021; v1 submitted 8 July, 2021; originally announced July 2021.

Comments: 35 pages, 12 figures

Improving radioactive contaminant identification through the analysis of delayed coincidences with an $α$-spectrometer

Authors: G. Baccolo, A. Barresi, M. Beretta, D. Chiesa, M. Nastasi, L. Pagnanini, S. Pozzi, E. Previtali, M. Sisti, G. Terragni

Abstract: In the framework of rare event searches, the identification of radioactive contaminants in ultra-pure samples is a challenging task, because the signal is often at the same level of the instrumental background. This is a rather common situation for $α$-spectrometers and other detectors used for low-activity measurements. In order to obtain the target sensitivity without extending the data taking l… ▽ More In the framework of rare event searches, the identification of radioactive contaminants in ultra-pure samples is a challenging task, because the signal is often at the same level of the instrumental background. This is a rather common situation for $α$-spectrometers and other detectors used for low-activity measurements. In order to obtain the target sensitivity without extending the data taking live-time, analysis strategies that highlight the presence of the signal sought should be developed. In this paper, we show how to improve the contaminant tagging capability relying on the time-correlation of radioactive decay sequences. We validate the proposed technique by measuring the impurity level of both contaminated and ultra-pure copper samples, demonstrating the potential of this analysis tool in disentangling different background sources and providing an effective way to mitigate their impact in rare event searches. △ Less

Submitted 9 November, 2021; v1 submitted 7 May, 2021; originally announced May 2021.

Journal ref: Eur. Phys. J. C 81, 971 (2021)

The Design and Sensitivity of JUNO's scintillator radiopurity pre-detector OSIRIS

Authors: JUNO Collaboration, Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Fengpeng An, Guangpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Andrej Babic, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Antonio Bergnoli, Thilo Birkenfeld , et al. (582 additional authors not shown)

Abstract: The OSIRIS detector is a subsystem of the liquid scintillator fillling chain of the JUNO reactor neutrino experiment. Its purpose is to validate the radiopurity of the scintillator to assure that all components of the JUNO scintillator system work to specifications and only neutrino-grade scintillator is filled into the JUNO Central Detector. The aspired sensitivity level of $10^{-16}$ g/g of… ▽ More The OSIRIS detector is a subsystem of the liquid scintillator fillling chain of the JUNO reactor neutrino experiment. Its purpose is to validate the radiopurity of the scintillator to assure that all components of the JUNO scintillator system work to specifications and only neutrino-grade scintillator is filled into the JUNO Central Detector. The aspired sensitivity level of $10^{-16}$ g/g of $^{238}$U and $^{232}$Th requires a large ($\sim$20 m$^3$) detection volume and ultralow background levels. The present paper reports on the design and major components of the OSIRIS detector, the detector simulation as well as the measuring strategies foreseen and the sensitivity levels to U/Th that can be reached in this setup. △ Less

Submitted 31 March, 2021; originally announced March 2021.

Comments: 32 pages, 22 figures

Detecting Reconnection Events in Kinetic Vlasov Hybrid Simulations Using Clustering Techniques

Authors: Manuela Sisti, Francesco Finelli, Giorgio Pedrazzi, Matteo Faganello, Francesco Califano, Francesca Delli Ponti

Abstract: Kinetic turbulence in magnetized space plasmas has been extensively studied via in situ observations, numerical simulations and theoretical models. In this context, a key point concerns the formation of coherent current structures and their disruption through magnetic reconnection. We present automatic techniques aimed at detecting reconnection events in large data set of numerical simulations. We… ▽ More Kinetic turbulence in magnetized space plasmas has been extensively studied via in situ observations, numerical simulations and theoretical models. In this context, a key point concerns the formation of coherent current structures and their disruption through magnetic reconnection. We present automatic techniques aimed at detecting reconnection events in large data set of numerical simulations. We make use of clustering techniques known as K-means and DBscan (usually referred in literature as unsupervised machine learning approaches), and other methods based on thresholds of standard reconnection proxies. All our techniques use also a threshold on the aspect ratio of the regions selected. We test the performance of our algorithms. We propose an optimal aspect ratio to be used in the automated machine learning algorithm: AR=18. The performance of the unsupervised approach results to be strongly competitive with respect to those of other methods based on thresholds of standard reconnection proxies. △ Less

Submitted 17 December, 2020; originally announced December 2020.

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

Authors: The CUPID Interest Group, A. Armatol, E. Armengaud, W. Armstrong, C. Augier, F. T. Avignone III, O. Azzolini, I. C. Bandac, A. S. Barabash, G. Bari, A. Barresi, D. Baudin, F. Bellini, G. Benato, M. Beretta, L. Bergé, Ch. Bourgeois, M. Biassoni, J. Billard, V. Boldrini, A. Branca, C. Brofferio, C. Bucci, J. M. Calvo-Mozota, J. Camilleri , et al. (156 additional authors not shown)

Abstract: A scintillating bolometer based on a large cubic Li$_{2}$$^{100}$MoO$_4$ crystal (45 mm side) and a Ge wafer (scintillation detector) has been operated in the CROSS cryogenic facility at the Canfranc underground laboratory in Spain. The dual-readout detector is a prototype of the technology that will be used in the next-generation $0\nu2β$ experiment CUPID. The measurements were performed at 18 an… ▽ More A scintillating bolometer based on a large cubic Li$_{2}$$^{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. △ Less

Submitted 27 November, 2020; originally announced November 2020.

Comments: 19 pages, 7 figures, 1 table

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

Authors: A. Armatol, E. Armengaud, W. Armstrong, C. Augier, F. T. Avignone III, O. Azzolini, A. Barabash, G. Bari, A. Barresi, D. Baudin, F. Bellini, G. Benato, M. Beretta, L. Bergè, M. Biassoni, J. Billard, V. Boldrini, A. Branca, C. Brofferio, C. Bucci, J. Camilleri, S. Capelli, L. Cappelli, L. Cardani, P. Carniti , et al. (147 additional authors not shown)

Abstract: 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}$$^{100}$MoO$_4$ crystals as suitable detectors for neutrinoless double beta… ▽ More The CUPID Collaboration is designing a tonne-scale, background-free detector to search for double beta decay with sufficient sensitivity to fully explore the parameter space corresponding to the inverted neutrino mass hierarchy scenario. One of the CUPID demonstrators, CUPID-Mo, has proved the potential of enriched Li$_{2}$$^{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. △ Less

Submitted 27 November, 2020; originally announced November 2020.

Novel technique for the study of pile-up events in cryogenic bolometers

Authors: A. Armatol, E. Armengaud, W. Armstrong, C. Augier, F. T. Avignone III, O. Azzolini, A. Barabash, G. Bari, A. Barresi, D. Baudin, F. Bellini, G. Benato, M. Beretta, L. Bergé, M. Biassoni, J. Billard, V. Boldrini, A. Branca, C. Brofferio, C. Bucci, J. Camilleri, S. Capelli, L. Cappelli, L. Cardani, P. Carniti , et al. (144 additional authors not shown)

Abstract: Precise characterization of detector time resolution is of crucial importance for next-generation cryogenic-bolometer experiments searching for neutrinoless double-beta decay, such as CUPID, in order to reject background due to pile-up of two-neutrino double-beta decay events. In this paper, we describe a technique developed to study the pile-up rejection capability of cryogenic bolometers. Our ap… ▽ More Precise characterization of detector time resolution is of crucial importance for next-generation cryogenic-bolometer experiments searching for neutrinoless double-beta decay, such as CUPID, in order to reject background due to pile-up of two-neutrino double-beta decay events. In this paper, we describe a technique developed to study the pile-up rejection capability of cryogenic bolometers. Our approach, which consists of producing controlled pile-up events with a programmable waveform generator, has the benefit that we can reliably and reproducibly control the time separation and relative energy of the individual components of the generated pile-up events. The resulting data allow us to optimize and benchmark analysis strategies to discriminate between individual and pile-up pulses. We describe a test of this technique performed with a small array of detectors at the Laboratori Nazionali del Gran Sasso, in Italy; we obtain a 90% rejection efficiency against pulser-generated pile-up events with rise time of ~15ms down to time separation between the individual events of about 2ms. △ Less

Submitted 12 July, 2021; v1 submitted 23 November, 2020; originally announced November 2020.

Journal ref: Phys. Rev. C 104, 015501 (2021)

New results from the CUORE experiment

Authors: A. Giachero, D. Q. Adams, C. Alduino, K. Alfonso, F. T. Avignone III, O. Azzolini, G. Bari, F. Bellini, G. Benato, M. Biassoni, A. Branca, C. Brofferio, C. Bucci, J. Camilleri, A. Caminata, A. Campani, L. Canonica, X. G. Cao, S. Capelli, L. Cappelli, L. Cardani, P. Carniti, N. Casali, E. Celi, D. Chiesa , et al. (88 additional authors not shown)

Abstract: The Cryogenic Underground Observatory for Rare Events (CUORE) is the first cryogenic experiment searching for neutrinoless double-beta ($0νββ$) decay that has been able to reach the one-ton scale. The detector, located at the Laboratori Nazionali del Gran Sasso in Italy, consists of an array of 988 TeO$_2$ crystals arranged in a compact cylindrical structure of 19 towers. Following the completion… ▽ More The Cryogenic Underground Observatory for Rare Events (CUORE) is the first cryogenic experiment searching for neutrinoless double-beta ($0νββ$) decay that has been able to reach the one-ton scale. The detector, located at the Laboratori Nazionali del Gran Sasso in Italy, consists of an array of 988 TeO$_2$ crystals arranged in a compact cylindrical structure of 19 towers. Following the completion of the detector construction in August 2016, CUORE began its first physics data run in 2017 at a base temperature of about 10 mK. Following multiple optimization campaigns in 2018, CUORE is currently in stable operating mode. In 2019, CUORE released its 2\textsuperscript{nd} result of the search for $0νββ$ with a TeO$_2$ exposure of 372.5 kg$\cdot$yr and a median exclusion sensitivity to a $^{130}$Te $0νββ$ decay half-life of $1.7\cdot 10^{25}$ yr. We find no evidence for $0νββ$ decay and set a 90\% C.I. (credibility interval) Bayesian lower limit of $3.2\cdot 10^{25}$ yr on the $^{130}$Te $0νββ$ decay half-life. In this work, we present the current status of CUORE's search for $0νββ$, as well as review the detector performance. Finally, we give an update of the CUORE background model and the measurement of the $^{130}$Te two neutrino double-beta ($2νββ$) decay half-life. △ Less

Submitted 7 January, 2021; v1 submitted 18 November, 2020; originally announced November 2020.

Comments: Proceeding of 40th International Conference on High Energy physics (ICHEP2020), July 28 - August 6, 2020, Prague, Czech Republic (virtual meeting). arXiv admin note: text overlap with arXiv:1905.07667