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Yeh, M.

Publications and source records attributed to Yeh, M..

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Eos: conceptual design for a demonstrator of hybrid optical detector technology

Eos is a technology demonstrator, designed to explore the capabilities of hybrid event detection technology, leveraging both Cherenkov and scintillation light simultaneously. With a fiducial mass of four tons, Eos is designed to operate in a high-precision regime, with sufficient size to utilize time-of-flight information for full event reconstruction, flexibility to demonstrate a range of cutting edge technologies, and simplicity of design to facilitate potential future deployment at alternative sites. Results from Eos can inform the design of future neutrino detectors for both fundamental physics and nonproliferation applications. This paper describes the conceptual design and potential applications of the Eos

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Identification of background limitations to ultra-sensitive $\mathrm{LSC}$ counting through $\mathrm{ICP}$-$\mathrm{MS}$ assay of $\mathrm{LSC}$ cocktails

We report the performance of LSC cocktails in ultra-sensitive applications was evaluated. Backgrounds from radioactive contaminations in commercially available and in-house developed liquid scintillation cocktails were measured and compared to the predicted background levels of the ultra-low background liquid scintillation counter. Through the ICP-MS assay of the cocktails and their constituents, potassium impurities in the surfactant component were identified as a significant source of background, potentially limiting the use of LSC counting in ultra-sensitive applications. This work lays the groundwork for future research towards ultrapure LSC cocktails for ultrasensitive LSC counting

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

PROSPECT-II physics opportunities

We report the precision reactor oscillation and spectrum experiment, PROSPECT, has made world-leading measurements of reactor antineutrinos at short baselines. In its first phase, conducted at the high flux isotope reactor (HFIR) at Oak Ridge National Laboratory, PROSPECT produced some of the strongest limits on eV-scale sterile neutrinos, made a precision measurement of the reactor antineutrino spectrum from 235 U, and demonstrated the observation of reactor antineutrinos in an aboveground detector with good energy resolution and well-controlled backgrounds. The PROSPECT collaboration is now preparing an upgraded detector, PROSPECT-II, to probe yet unexplored parameter space for sterile neutrinos and contribute to a full resolution of the reactor antineutrino anomaly, a longstanding puzzle in neutrino physics. By pressing forward on the world’s most precise measurement of the 235 U antineutrino spectrum and measuring the absolute flux of antineutrinos from 235 U, PROSPECT-II will sharpen a tool with potential value for basic neutrino science, nuclear data validation, and nuclear security applications. Following a two-year deployment at HFIR, an additional PROSPECT-II deployment at a low enriched uranium reactor could make complementary measurements of the neutrino yield from other fission isotopes. PROSPECT-II provides a unique opportunity to continue the study of reactor antineutrinos at short baselines, taking advantage of demonstrated elements of the original PROSPECT design and close access to a highly enriched uranium reactor core.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Characterization of the correlated background for a sterile neutrino search using the first dataset of the JSNS$^2$ experiment

JSNS 2 (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) is an experiment that is searching for sterile neutrinos via the observation of ν¯ μ → ν¯ e appearance oscillations using muon decay-at-rest neutrinos. Before dedicated data taking in the first-half of 2021, we performed a commissioning run for 10 days in June 2020. Using the data obtained in this commissioning run, in this paper, we present an estimate of the correlated background which imitates the ν¯ e signal in a sterile neutrino search. In addition, in order to demonstrate future prospects of the JSNS 2 experiment, possible pulse shape discrimination improvements towards reducing cosmic ray induced fast neutron background are described.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Cherenkov and scintillation separation in water-based liquid scintillator using an LAPPDTM

Abstract This manuscript describes measurements of water-based liquid scintillators (WbLS), demonstrating separation of the Cherenkov and scintillation components using a low energy $$\beta $$ β source and the fast timing response of a Large Area Picosecond Photodetector (LAPPD). Additionally, the time profiles of three WbLS mixtures, defined by the relative fractions of scintillating compound, are characterized, with improved sensitivity to the scintillator rise-time. The measurements were made using both an LAPPD and a conventional photomultiplier tube (PMT). All samples were measured with an effective resolution $$O\left( 100~\text {ps}\right) $$ O 100 ps , which allows for the separation of Cherenkov and scintillation light (henceforth C/S separation) by selecting on the arrival time of the photons alone. The Cherenkov purity of the selected photons is greater than 60% in all cases, with greater than 80% achieved for a sample containing 1% scintillator. This is the first demonstration of the power of synthesizing low light yield scintillators, of which WbLS is the canonical example, with fast photodetectors, of which LAPPDs are an emerging leader, and has direct implication for future mid- and large-scale detectors, such as Theia , ANNIE, and AIT-NEO.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Joint Measurement of the 235 U Antineutrino Spectrum by PROSPECT and STEREO

The PROSPECT and STEREO collaborations present a combined measurement of the pure 235 U antineutrino spectrum, without site specific corrections or detector-dependent effects. The spectral measurements of the two highest precision experiments at research reactors are found to be compatible with χ 2 /ndf = 24.1/21, allowing a joint unfolding of the prompt energy measurements into antineutrino energy. This $\bar{ν}_e$ energy spectrum is provided to the community, and an excess of events relative to the Huber model is found in the 5-6 MeV region. When a Gaussian bump is fitted to the excess, the data-model χ 2 value is improved, corresponding to a 2.4σ significance.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

The JSNS 2 detector

The JSNS 2 (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) experiment aims to search for oscillations involving a sterile neutrino in the eV 2 mass-splitting range. The experiment will search for the appearance of electron antineutrinos oscillated from muon antineutrinos. The electron antineutrinos are detected via the inverse beta decay process using a liquid scintillator detector. A 1 MW beam of 3 GeV protons incident on a spallation neutron target produces an intense and pulsed neutrino source from pion, muon, and kaon decay at rest. The JSNS detector is located 24 m away from the neutrino source and began operation from June 2020. The detector contains 17 tonnes of gadolinium (Gd) loaded liquid scintillator (LS) in an acrylic vessel, as a neutrino target. It is surrounded by 31 tonnes of unloaded LS in a stainless steel tank. Optical photons produced in LS are viewed by 120 R7081 Hamamatsu 10-inch Photomultiplier Tubes (PMTs). In this study, we describe the JSNS detector design, construction, and operation.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

Slow control and monitoring system at the JSNS 2

The Sterile Neutrino Search at the J-PARC Spallation Neutron Source (JSNS$^2$) experiment aims to search for sterile neutrino oscillations using a neutrino beam from muon decays at rest. The JSNS$^2$ detector contains 17 tons of 0.1$\%$ gadolinium (Gd) loaded liquid scintillator (LS) as a neutrino target. Detector construction was completed in the spring of 2020. A slow control and monitoring system (SCMS) was implemented for reliable control and quick monitoring of the detector operational status and environmental conditions. It issues an alarm if any of the monitored parameters exceed a preset acceptable range. The SCMS monitors the high voltage of the photomultiplier tubes, the LS level in the detector, possible LS overflow and leakage, the temperature and air pressure in the detector, the humidity of the experimental hall, and the LS flow rate during filling and extraction. An initial 10 days of data-taking with a neutrino beam was done following a successful commissioning of the detector and SCMS in 2020 June. In this paper, we present a description of the assembly and installation of the SCMS and its performance.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Light yield quenching and quenching remediation in liquid scintillator detectors

Quenching of light emission from an LAB based scintillator by the addition of organic amines and carboxylic acids is examined. Chemical functional groups of the quenching agents play an important role in this reduction. It is shown that "salt" formation at a 1:1 mole ratio in a mixed amine-acid system, reduces quenching by a factor of ~ 2. Supporting NMR spectra are presented. Finally, this "quenching neutralization" has the potential to reduce the light loss incurred when metals complexed with quenching agents are loaded into organic scintillators.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

Characterization of water-based liquid scintillator for Cherenkov and scintillation separation

Abstract This paper presents measurements of the scintillation light yield and time profile for a number of concentrations of water-based liquid scintillator, formulated from linear alkylbenzene (LAB) and 2,5-diphenyloxazole (PPO). We find that the scintillation light yield is linear with the concentration of liquid scintillator in water between 1 and 10% with a slope of $$127.9\pm 17.0$$ 127.9 ± 17.0 ph/MeV/concentration and an intercept value of $$108.3\pm 51.0$$ 108.3 ± 51.0 ph/MeV, the latter being illustrative of non-linearities with concentration at values less than 1%. This is larger than expected from a simple extrapolation of the pure liquid scintillator light yield. The measured time profiles are consistently faster than that of pure liquid scintillator, with rise times less than 250 ps and prompt decay constants in the range of 2.1–2.85 ns. Additionally, the separation between Cherenkov and scintillation light is quantified using cosmic muons in the CHESS experiment for each formulation, demonstrating an improvement in separation at the centimeter scale. Finally, we briefly discuss the prospects for large-scale detectors.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Performance of PMTs for the JSNS 2 experiment

The JSNS 2 (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) experiment aims to search for neutrino oscillations over a 24 m short baseline at J-PARC. The JSNS 2 inner detector is filled with 17 tons of gadolinium-loaded liquid scintillator (LS) and both the intermediate γ-catcher and the optically separated outer veto are filled with un-loaded LS. Optical photons from scintillation are observed by 120 Photomultiplier Tubes (PMTs). A total of 130 PMTs for the JSNS 2 experiment were both donated by other experiments and purchased from Hamamatsu. Donated PMTs were purchased around 10 years ago, therefore JSNS 2 did pre-calibration of the PMTs including the purchased PMTs. 123 PMTs demonstrated acceptable performance for the JSNS 2 experiment, and 120 PMTs were installed in the detector.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

Nonfuel antineutrino contributions in the ORNL High Flux Isotope Reactor (HFIR)

Reactor neutrino experiments have seen major improvements in precision in recent years. With the experimental uncertainties becoming lower than those from theory, carefully considering all sources of $\bar{ν}$ e is important when making theoretical predictions. One source of νe that is often neglected arises from the irradiation of the nonfuel materials in reactors. The $\bar{ν}$ e rates and energies from these sources vary widely based on the reactor type, configuration, and sampling stage during the reactor cycle and have to be carefully considered for each experiment independently. In this article, we present a formalism for selecting the possible $\bar{ν}$ e sources arising from the neutron captures on reactor and target materials. We apply this formalism to the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, the $\bar{ν}$ e source for the the Precision Reactor Oscillation and Spectrum Measurement (PROSPECT) experiment. Overall, we observe that the nonfuel $\bar{ν}$ e contributions from HFIR to PROSPECT amount to 1% above the inverse beta decay threshold with a maximum contribution of 9% in the 1.8–2.0 MeV range. Nonfuel contributions can be particularly high for research reactors like HFIR because of the choice of structural and reflector material in addition to the intentional irradiation of target material for isotope production. We show that typical commercial pressurized water reactors fueled with low-enriched uranium will have significantly smaller nonfuel $\bar{ν}$ e contribution.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2019

Deuterium and helium ion irradiation of nanograined tungsten and tungsten–titanium alloys

Tungsten (W), a primary candidate for the plasma-facing components of nuclear fusion reactors (e.g. the divertor region in ITER) is susceptible to cracks, blisters, bubbles, and other morphological changes when irradiated with energetic particles. This work investigated two new materials, nanograined W and a nanograined W–Ti alloy, for potential use as plasma-facing materials. Their retention properties and morphological changes after exposure to deuterium (D) and helium (He) plasma at 50 eV and surface temperatures of 500 and 1000 K were analyzed. Nanograined W was found to have smaller blisters and be less prone to fuzz formation than commonly-utilized micro-grain polycrystalline W. Additionally, the nanograined W–Ti alloy exhibited a lower concentration of blisters on its surface than pure W, including nanograined W.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

The radioactive source calibration system of the PROSPECT reactor antineutrino detector

The Precision Reactor Oscillation and Spectrum (PROSPECT) Experiment is a reactor neutrino experiment created to search for sterile neutrinos with a mass on the order of 1 eV/c 2 and to measure the spectrum of electron antineutrinos from a highly-enriched 235 U nuclear reactor. The PROSPECT detector consists of an 11 by 14 array of optical segments in 6 Li-loaded liquid scintillator at the High Flux Isotope Reactor in Oak Ridge National Laboratory. Antineutrino events are identified via inverse beta decay and read out by photomultiplier tubes located at the ends of each segment. The detector response is characterized using a radioactive source calibration system. Here, we describe the design, operation, and performance of the PROSPECT source calibration system.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

A liquid scintillation detector for radioassay of gadolinium-loaded liquid scintillator for the LZ Outer Detector

© 2019 Elsevier B.V. We report on the design and performance of the LUX-ZEPLIN (LZ) “Screener”, a small liquid scintillator detector consisting of ≈23 kg of LAB-based gadolinium-loaded liquid scintillator (GdLS) to be used in the LZ Outer Detector. The Outer Detector will be filled with 17.3 tonnes of GdLS and will surround the central liquid xenon time projection chamber of LZ. Its primary function will be to tag neutron events in the liquid xenon which could mimic a WIMP dark matter signal. To meet the deadtime requirements for the Outer Detector, the radioimpurity levels in the GdLS must be kept below ≲0.07 mBq/kg. This background level corresponds to a rate of ≈50Hz above an energy threshold of 100 keV. The Screener was operated in the ultra-low-background environment of the former LUX water shield in the Davis Laboratory at the Sanford Underground Research Facility for radioassay of the GdLS. Careful selection of detector materials and use of ultra-low-background PMTs allows the measurement of a variety of radioimpurities. The 14C/12C ratio in the scintillator is measured to be (2.83±0.06(stat.)±0.01(sys.))×10 -17 . Use of pulse shape discrimination allows the concentration of isotopes throughout the 238U, 235U, and 232Th chains to be measured by fitting the collected spectra from α and β events. We find that equilibrium is broken in the 238U and 232Th chains and that a significant portion of the contamination in the GdLS results from decays in the 227Ac subchain of the 235U series. Predictions for the singles rate in the Outer Detector are presented. The rate from radioimpurities above 100 keV in the GdLS is estimated to be 97.9±6.4Hz, with 65.5±1.9Hz resulting from α-decays.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗