Abstract
Supernovae emit large fluxes of neutrinos, which can be detected by detectors on Earth. Future multi-kiloton scale detectors will be sensitive to several neutrino interaction channels, with ...thousands of events expected if a supernova emerges in the galaxy neighborhood. There are a limited number of tools to study the interaction rates of supernova neutrinos, although a plethora of available supernova models exist. EstrellaNueva is an open-source software to calculate expected rates of supernova neutrinos in detectors using target materials with typical compositions, and additional compositions can be easily added. This software considers the flavor transformation of neutrinos in the supernova through the adiabatic Mikheyev–Smirnov–Wolfenstein effect, and their interaction in detectors through several channels. Most of the interaction cross sections, such as neutrino–electron and neutrino–proton elastic scattering, inverse beta decay, and coherent elastic neutrino–nucleus scattering, have been analytically implemented. This software provides a link between supernova simulations and the expected events in detectors by calculating fluences and event rates in order to ease any comparison between theory and observation. It provides a simple and standalone tool to explore many physics scenarios, offering an option to add analytical cross sections and define any target material.
The SNO+ Collaboration reports the first evidence of reactor antineutrinos in a Cherenkov detector. The nearest nuclear reactors are located 240 km away in Ontario, Canada. This analysis uses events ...with energies lower than in any previous analysis with a large water Cherenkov detector. Two analytical methods are used to distinguish reactor antineutrinos from background events in 190 days of data and yield consistent evidence for antineutrinos with a combined significance of 3.5σ.
The direction of individual
B
8
solar neutrinos has been reconstructed using the
SNO
+
liquid scintillator detector. Prompt, directional Cherenkov light was separated from the slower, isotropic ...scintillation light using time information, and a maximum likelihood method was used to reconstruct the direction of individual scattered electrons. A clear directional signal was observed, correlated with the solar angle. The observation was aided by a period of low primary fluor concentration that resulted in a slower scintillator decay time. This is the first time that event-by-event direction reconstruction in high light-yield liquid scintillator has been demonstrated in a large-scale detector.
Published by the American Physical Society
2024
The SNO+ experiment Arushanova, E.; Askins, M.; Back, S. ...
Journal of instrumentation,
08/2021, Letnik:
16, Številka:
8
Journal Article
Recenzirano
The SNO+ experiment is located 2 km underground at SNOLAB in Sudbury, Canada. A low background search for neutrinoless double beta (0νββ) decay will be conducted using 780 tonnes of liquid ...scintillator loaded with 3.9 tonnes of natural tellurium, corresponding to 1.3 tonnes of 130Te. This paper provides a general overview of the SNO+ experiment, including detector design, construction of process plants, commissioning efforts, electronics upgrades, data acquisition systems, and calibration techniques. The SNO+ collaboration is reusing the acrylic vessel, PMT array, and electronics of the SNO detector, having made a number of experimental upgrades and essential adaptations for use with the liquid scintillator. With low backgrounds and a low energy threshold, the SNO+ collaboration will also pursue a rich physics program beyond the search for 0νββ decay, including studies of geo- and reactor antineutrinos, supernova and solar neutrinos, and exotic physics such as the search for invisible nucleon decay. The SNO+ approach to the search for 0νββ decay is scalable: a future phase with high 130Te-loading is envisioned to probe an effective Majorana mass in the inverted mass ordering region.
Abstract
A liquid scintillator consisting of linear alkylbenzene as the solvent and 2,5-diphenyloxazole as the fluor was developed for the SNO+ experiment.
This mixture was chosen as it is compatible ...with acrylic and has a competitive light yield to pre-existing liquid scintillators while conferring other advantages including longer attenuation lengths, superior safety characteristics, chemical simplicity, ease of handling, and logistical availability.
Its properties have been extensively characterized and are presented here.
This liquid scintillator is now used in several neutrino physics experiments in addition to SNO+.
SNO+ is a large-scale liquid scintillator experiment with the primary goal of searching for neutrinoless double beta decay, and is located approximately 2 km underground in SNOLAB, Sudbury, Canada. ...The detector acquired data for two years as a pure water Cherenkov detector, starting in May 2017. During this period, the optical properties of the detector were measured in situ using a deployed light diffusing sphere, with the goal of improving the detector model and the energy response systematic uncertainties. The measured parameters included the water attenuation coefficients, effective attenuation coefficients for the acrylic vessel, and the angular response of the photomultiplier tubes and their surrounding light concentrators, all across different wavelengths. The calibrated detector model was validated using a deployed tagged gamma source, which showed a 0.6% variation in energy scale across the primary target volume.
Supernovae emit large fluxes of neutrinos which can be detected by detectors on Earth. Future tonne-scale detectors will be sensitive to several neutrino interaction channels, with thousands of ...events expected if a supernova emerges in the galaxy neighborhood. There is a limited number of tools to study the interaction rates of supernova neutrinos, although a plethora of available supernova models exists. EstrellaNueva is an open-source software to calculate expected rates of supernova neutrinos in detectors using target materials with typical compositions, and additional compositions can be easily added. This software considers the flavor transformation of neutrinos in the supernova through the adiabatic Mikheyev--Smirnov--Wolfenstein effect, and their interaction in detectors through several channels. Most of the interaction cross sections have been analytically implemented, such as neutrino-electron and neutrino-proton elastic scattering, inverse beta decay, and coherent elastic neutrino-nucleus scattering. This software provides a link between supernova simulations and the expected events in detectors by calculating fluences and event rates to ease any comparison between theory and observation. It provides a simple and standalone tool to explore many physics scenarios offering an option to add analytical cross sections and define any target material.
This paper reports results from a search for single and multi-nucleon disappearance from the \(^{16}\)O nucleus in water within the \snoplus{} detector using all of the available data. These ...so-called "invisible" decays do not directly deposit energy within the detector but are instead detected through their subsequent nuclear de-excitation and gamma-ray emission. New limits are given for the partial lifetimes: \(\tau(n\rightarrow inv) > 9.0\times10^{29}\) years, \(\tau(p\rightarrow inv) > 9.6\times10^{29}\) years, \(\tau(nn\rightarrow inv) > 1.5\times10^{28}\) years, \(\tau(np\rightarrow inv) > 6.0\times10^{28}\) years, and \(\tau(pp\rightarrow inv) > 1.1\times10^{29}\) years at 90\% Bayesian credibility level (with a prior uniform in rate). All but the (\(nn\rightarrow inv\)) results improve on existing limits by a factor of about 3.
SNO+ is a large-scale liquid scintillator experiment with the primary goal of searching for neutrinoless double beta decay, and is located approximately 2 km underground in SNOLAB, Sudbury, Canada. ...The detector acquired data for two years as a pure water Cherenkov detector, starting in May 2017. During this period, the optical properties of the detector were measured in situ using a deployed light diffusing sphere, with the goal of improving the detector model and the energy response systematic uncertainties. The measured parameters included the water attenuation coefficients, effective attenuation coefficients for the acrylic vessel, and the angular response of the photomultiplier tubes and their surrounding light concentrators, all across different wavelengths. The calibrated detector model was validated using a deployed tagged gamma source, which showed a 0.6% variation in energy scale across the primary target volume.
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