arXiv subjects

G. D. Orebi Gann

Publications and source records attributed to G. D. Orebi Gann.

At least 19 recordsLinked to original sources

arXiv2026

Performance of the Eos detector with water

In this manuscript we present the first results from Eos, a four tonne optical detector located at the University of California, Berkeley. The primary goal of Eos is to demonstrate the performance capabilities of scintillation-based, 'hybrid' detector technology for future neutrino detectors. The data presented were collected while both the inner target vessel and the outer buffer vessel were filled with water. The water target acts as a well-understood medium that produces only Cherenkov light, which can be used to calibrate and develop the detector model and reconstruction algorithms prior to the deployment of scintillating material. Using deployed optical and radioactive calibration sources, a series of detailed detector calibrations are performed. These enable a suite of tests for various reconstruction algorithms. Simulations that use calibrated models are compared with the data across a variety of different types of calibration sources, source positions, and rotations.

hep-ex↗

arXiv2026

Design, construction, and initial operation of a 30-ton Water-based Liquid scintillator detector at Brookhaven National Laboratory

Water-based Liquid Scintillator (WbLS) was proposed over a decade ago as a novel detector medium that might allow the separation and tuning of the relative ratio of the Cherenkov and scintillation signals. A detector employing this technology could support large-scale neutrino detection over both the GeV and MeV energy regimes, while its metal-loading capability could provide an effective means of neutron tagging. WbLS is attractive for two reasons. It can be deployed in very large detectors. It also allows in-situ tuning of the scintillator concentration, and hence the ratio of Cherenkov to scintillation light. Neither pure water Cherenkov detectors nor conventional liquid scintillator detectors offer this capability. At Brookhaven National Laboratory (BNL), two prototypes have been built for understanding WbLS properties and stability, with masses of 1-ton and 30-ton, respectively. We present here the 30-ton prototype detector design, installation, and initial operation including the real-time observation of a transient optical response during the staged scintillator injection. Results from the analysis of data collected in the two detectors will follow in separate publications.

physics.ins-det↗

arXiv2026

Reconstruction of neutrino events in the Accelerator Neutrino Neutron Interaction Experiment: Part I

The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) was designed to reconstruct neutrino events from the Fermilab Booster Neutrino Beam (BNB) with the parallel goals of measuring neutron production in interactions with oxygen and serving as a testbed for new technology. The ANNIE detector consists of a 26-ton water Cherenkov target tank instrumented with conventional photomultiplier tubes (PMTs), a downstream tracking muon spectrometer, and an upstream double wall of plastic scintillator to serve to veto charged particles incoming from neutrino events that occur upstream of the experimental setup. ANNIE has also deployed multiple Large-Area Picosecond PhotoDetectors (LAPPDs) and a test vessel of water-based liquid scintillator (WbLS). This paper describes the event reconstruction performance of the detector before implementation of these novel technologies, which will serve as a baseline against which their impact can be measured. That said, even the techniques used for event reconstruction using only the conventional PMT array and muon spectrometer are significantly different than those used in other water Cherenkov detectors due to the small size of ANNIE (which makes nanosecond-scale timing not as useful as in a large detector) and the availability of reconstruction information from the tracking muon spectrometer. We demonstrate that combining the information from these two elements into a single fit using only pattern recognition yields a muon vertex uncertainty of 60 cm, a directional uncertainty of 13.2 degrees, and energy reconstruction uncertainty of about 10\% for BNB muon neutrino Charged Current Zero Pion (CC0pi) events.

hep-ex↗

arXiv2026

The Eos detector: a demonstrator of hybrid optical detection technology

Eos is an R&D testbed for hybrid detector technologies, featuring state-of-the-art sub-ns photosensors, the first implementation of dichroicons in a large-scale demonstrator, and the deployment of novel detection media such as water-based liquid scintillator (WbLS). By separating Cherenkov and scintillation light, Eos leverages the benefits of both to explore the potential of next-generation neutrino technologies. An extensive radioactive source calibration program enables the characterization of position, direction, and energy reconstruction performance of a variety of target materials. Furthermore, Eos will provide data to refine optical models and inform the development and simulation of future neutrino experiments. This paper describes the as-built design and data-taking plan of Eos, outlining its scientific motivations and role in the development of future detector technologies.

physics.ins-det↗

arXiv2026

Neutrino monitoring of explosions for excluding fission yield

Nuclear fission produces neutrinos, so the absence of a neutrino signal can be used to set a limit on the fission content of an explosion. This capability could be employed on former nuclear test sites to assure regulators, international monitors, or other observers that activities involving chemical explosions do not exceed a designated limit for nuclear fission. This paper quantifies the neutrino detector masses that would be required to set fission yield limits at source-to-detector distances up to 100 km, assuming detection by inverse beta decay with realistic background levels. The analysis indicates that detectors with active mass in the ton- to tens-of-kiloton range can set potentially useful limits on the fission yield of large chemical explosions at the Nevada National Security Site. In contrast, inverse beta decay detectors are not well suited to excluding fission yield at longer range or in the subcritical nuclear experiments that have occurred at some test sites following the cessation of explosive nuclear testing.

physics.soc-ph↗

arXiv2026

Cosmogenic Neutron Production in Water at SNO+

Accurate measurement of the cosmogenic muon-induced neutron yield is crucial for constraining a significant background in a wide range of low-energy physics searches. Although previous underground experiments have measured this yield across various cosmogenic muon energies, SNO+ is uniquely positioned due to its exposure to one of the highest average cosmogenic muon energies at $364\,\text{GeV}$. Using ultra-pure water, we have determined a neutron yield of $Y_{n}=(3.38^{+0.23}_{-0.30})\times10^{-4}\,\text{cm}^{2}\text{g}^{-1}μ^{-1}$ at SNO+. Comparison with simulations demonstrates clear agreement with the FLUKA neutron production model, highlighting discrepancies with the widely used GEANT4 model. Furthermore, this measurement reveals a lower cosmogenic neutron yield than that observed by the SNO experiment, which used heavy water under identical muon flux conditions. This result provides new evidence that nuclear structure and target material composition significantly influence neutron production by cosmogenic muons, offering fresh insight with important implications for the design and background modelling of future underground experiments.

hep-ex↗

arXiv2026

The BUTTON-30 detector at Boulby

The BUTTON-30 detector is a 30-tonne technology demonstrator designed to evaluate the potential of hybrid event detection, simultaneously exploiting both Cherenkov and scintillation light to detect particles produced in neutrino interactions. The detector is installed at a depth of 1.1 km in the Boulby Underground Laboratory allowing to test the performance of this new technology underground in a low background environment. This paper describes the design and construction of the experiment.

physics.ins-det↗

arXiv2026

Design and development of optical modules for the BUTTON-30 detector

BUTTON-30 is a neutrino detector demonstrator located in the STFC Boulby underground facility in the north-east of England. The main goal of the project is to deploy and test the performance of the gadolinium-loaded water-based liquid scintillator for neutrino detection in an underground environment. This will pave the way for a future large-volume neutrino observatory that can also perform remote monitoring of nuclear reactors for nonproliferation. This paper describes the design and construction of the watertight optical modules of the experiment.

physics.ins-det↗

arXiv2026

First Light from Beam Neutrinos on an LAPPD in ANNIE

The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) is both a physics experiment and a technology testbed for next-generation light-based neutrino detection. In this paper, we report the first demonstration of a fully integrated Large Area Picosecond Photodetector (LAPPD) operating in a running neutrino beam experiment. Particular focus is given to the design, commissioning, and successful deployment of the Packaged ANNIE LAPPD (PAL), a waterproof, self-triggering module incorporating fast waveform digitization and precision timing synchronized to the ANNIE detector subsystems. We identify beam-correlated LAPPD data frames consistent with charged-current neutrino interactions observed in multiple detector subsystems, establishing the first detection of neutrino-induced Cherenkov light with an LAPPD. These results validate the system-level performance of LAPPDs under realistic experimental conditions-including long-term stability, timing synchronization, and event matching with conventional PMT and muon detector systems-marking a critical step toward their deployment in future large-scale neutrino and particle detectors.

hep-ex↗

arXiv2025

Measurement of Light Yield Response of Gd-compatible Water-based Liquid Scintillator with the Brookhaven 1-ton testbed

The Water-based Liquid Scintillator (WbLS) enables hybrid detection by combining scintillation and Cherenkov signals, providing superior event reconstruction capabilities compared to conventional neutrino detectors. We measured the light yield of Gd-compatible WbLS at varying concentrations from 0.35\% to 1\% by mass, using cosmic-ray muons in a 1-ton scale detector at BNL. The light yield is measured as (69.16 $\pm$ 6.92) ph / MeV at 0.35\% concentration, which increased to (87.32 $\pm$ 8.73) ph / MeV at 1\%. These results establish a quantitative basis for optimizing future WbLS-based detectors in neutrino physics.

physics.ins-det↗

arXiv2025

First Evidence of Solar Neutrino Interactions on $^{13}$C

The SNO+ Collaboration reports the first evidence of $^{8}\text{B}$ solar neutrinos interacting on $^{13}\text{C}$ nuclei. The charged current interaction proceeds through $^{13}\text{C} + ν_e \rightarrow {}^{13}\text{N} + e^-$ which is followed, with a 10 minute half-life, by ${}^{13}\text{N} \rightarrow {}^{13}\text{C} + e^+ +ν_e .$ The detection strategy is based on the delayed coincidence between the electron and the positron. Evidence for the charged current signal is presented with a significance of 4.2$σ$. Using the natural abundance of $^{13}\text{C}$ present in the scintillator, 5.7 tonnes of $^{13}\text{C}$ over 231 days of data were used in this analysis. The 5.6$^{+3.0}_{-2.3}$ observed events in the data set are consistent with the expectation of 4.7$^{+0.6}_{-1.3}$ events. This result is the second real-time measurement of CC interactions of $^{8}\text{B}$ neutrinos with nuclei and constitutes the lowest energy observation of neutrino interactions on $^{13}\text{C}$ generally. This enables the first direct measurement of the CC $ν_e$ reaction to the ground state of ${}^{13}\text{N}$, yielding an average cross section of $(16.1 ^{+8.5}_{-6.7} (\text{stat.}) ^{+1.6}_{-2.7} (\text{syst.}) )\times 10^{-43}$ cm$^{2}$ over the relevant $^{8}\text{B}$ solar neutrino energies.

nucl-ex↗

arXiv2025

Solar fusion III: New data and theory for hydrogen-burning stars

In stars that lie on the main sequence in the Hertzsprung-Russel diagram, like our sun, hydrogen is fused to helium in a number of nuclear reaction chains and series, such as the proton-proton chain and the carbon-nitrogen-oxygen cycles. Precisely determined thermonuclear rates of these reactions lie at the foundation of the standard solar model. This review, the third decadal evaluation of the nuclear physics of hydrogen-burning stars, is motivated by the great advances made in recent years by solar neutrino observatories, putting experimental knowledge of the proton-proton chain neutrino fluxes in the few-percent precision range. The basis of the review is a one-week community meeting held in July 2022 in Berkeley, California, and many subsequent digital meetings and exchanges. The relevant reactions of solar and stellar hydrogen burning are reviewed here, from both theoretical and experimental perspectives. Recommendations for the state of the art of the astrophysical S-factor and its uncertainty are formulated for each of them. Several other topics of paramount importance for the solar model are reviewed, as well: recent and future neutrino experiments, electron screening, radiative opacities, and current and upcoming experimental facilities. In addition to reaction-specific recommendations, also general recommendations are formed.

astro-ph.SR↗

arXiv2025

Initial measurement of reactor antineutrino oscillation at SNO+

The SNO+ collaboration reports its first spectral analysis of long-baseline reactor antineutrino oscillation using 114 tonne-years of data. Fitting the neutrino oscillation probability to the observed energy spectrum yields constraints on the neutrino mass-squared difference $Δm^2_{21}$. In the ranges allowed by previous measurements, the best-fit $Δm^2_{21}$ is (8.85$^{+1.10}_{-1.33}$) $\times$ 10$^{-5}$ eV$^2$. This measurement is continuing in the next phases of SNO+ and is expected to surpass the present global precision on $Δm^2_{21}$ with about three years of data.

hep-ex↗

arXiv2024

Measurement of the $^8$B Solar Neutrino Flux Using the Full SNO+ Water Phase Dataset

The SNO+ detector operated initially as a water Cherenkov detector. The implementation of a sealed covergas system midway through water data taking resulted in a significant reduction in the activity of $^{222}$Rn daughters in the detector and allowed the lowest background to the solar electron scattering signal above 5 MeV achieved to date. This paper reports an updated SNO+ water phase $^8$B solar neutrino analysis with a total livetime of 282.4 days and an analysis threshold of 3.5 MeV. The $^8$B solar neutrino flux is found to be $\left(2.32^{+0.18}_{-0.17}\text{(stat.)}^{+0.07}_{-0.05}\text{(syst.)}\right)\times10^{6}$ cm$^{-2}$s$^{-1}$ assuming no neutrino oscillations, or $\left(5.36^{+0.41}_{-0.39}\text{(stat.)}^{+0.17}_{-0.16}\text{(syst.)} \right)\times10^{6}$ cm$^{-2}$s$^{-1}$ assuming standard neutrino oscillation parameters, in good agreement with both previous measurements and Standard Solar Model Calculations. The electron recoil spectrum is presented above 3.5 MeV.

hep-ex↗

arXiv2024

Design, construction, and operation of a 1-ton Water-based Liquid scintillator detector at Brookhaven National Laboratory

Water-based liquid scintillators (WbLS) are attractive neutrino detector materials because they allow us to tune the ratio of the Cherenkov and scintillation signals. Using WbLS large-scale neutrino experiments can benefit from both directional reconstruction and enhanced low-energy efficiency. Furthermore, broadening the science capability of such materials by metal doping may be better suited for water based liquid scintillators. We recently constructed and commissioned a 1-ton WbLS detector with good photosensor coverage and a capable data acquisition system. We intend to use this flexible detector system as a testbed for WbLS R&D. In this paper we give an overview of the 1-ton system and provide some early analysis results.

physics.ins-det↗

arXiv2024

Event-by-Event Direction Reconstruction of Solar Neutrinos in a High Light-Yield Liquid Scintillator

The direction of individual $^8$B 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.

hep-ex↗

arXiv2024

Deployment of Water-based Liquid Scintillator in the Accelerator Neutrino Neutron Interaction Experiment

The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) is a 26-ton water Cherenkov neutrino detector installed on the Booster Neutrino Beam (BNB) at Fermilab. Its main physics goals are to perform a measurement of the neutron yield from neutrino-nucleus interactions, as well as a measurement of the charged-current cross section of muon neutrinos. An equally important focus is placed on the research and development of new detector technologies and target media. Specifically water-based liquid scintillator (WbLS) is of interest as a novel detector medium, as it allows for the simultaneous detection of scintillation and Cherenkov light. This paper presents the deployment of a 366L WbLS vessel in ANNIE in March 2023 and the subsequent detection of both Cherenkov light and scintillation from the WbLS. This proof-of-concept allows for the future development of reconstruction and particle identification algorithms in ANNIE, as well as dedicated analyses, such as the search for neutral current events and the hadronic scintillation component within the WbLS volume.

hep-ex↗

arXiv2023

Characterization of the scintillation response of water-based liquid scintillator to alpha particles, and implications for particle identification

Next-generation large-scale neutrino detectors, from Eos, at the 1 tonne scale, to Theia, at the 10s-of-ktonne scale, will utilize differences in both the scintillation and Cherenkov light emission for different particle species to perform background rejection. This manuscript presents measurements of the scintillation light yield and emission time profile of water-based liquid scintillator samples in response to $α$ radiation. These measurements are used as input to simulation models used to make predictions for future detectors. In particular, we present the timing-based particle identification achievable in generic water-based scintillator detectors at the 4 tonne, 1 ktonne, and 100 ktonne scales. We find that $α$/$β$ discrimination improves with increasing scintillation concentration and we identify better than 80% $α$ rejection for 90% $β$ acceptance in 10% water-based liquid scintillator, at the 4 tonne scale.

hep-ex↗