A5039528961- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Astrophysics and Cosmic Phenomena
- Radiation Detection and Scintillator Technologies
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Superconducting and THz Device Technology
- Nuclear Physics and Applications
- Radioactive contamination and transfer
- Nuclear physics research studies
- Radioactivity and Radon Measurements
- Nuclear reactor physics and engineering
- Atmospheric Ozone and Climate
- Quantum, superfluid, helium dynamics
- Evolutionary Algorithms and Applications
- Microwave Engineering and Waveguides
- Radiation Therapy and Dosimetry
- Photocathodes and Microchannel Plates
- Music and Audio Processing
- Economic and Business Development Strategies
- Millimeter-Wave Propagation and Modeling
- Stock Market Forecasting Methods
- CCD and CMOS Imaging Sensors
- Analog and Mixed-Signal Circuit Design
University of Alabama
2014-2024
McGill University
2021
Lawrence Berkeley National Laboratory
2014-2020
Pacific Northwest National Laboratory
2018-2020
University of California, Berkeley
2020
Brookhaven National Laboratory
2019-2020
Institute of High Energy Physics
2017
University of Hong Kong
2013-2016
Chinese University of Hong Kong
2016
California Institute of Technology
2012-2015
Results from a search for neutrinoless double-beta decay (0νββ) of ^{136}Xe are presented using the first year data taken with upgraded EXO-200 detector. Relative to previous searches by EXO-200, energy resolution detector has been improved σ/E=1.23%, electric field in drift region raised 50%, and system suppress radon volume between cryostat lead shielding implemented. In addition, analysis techniques that improve topological discrimination 0νββ background events have developed....
A search for Lorentz- and $CPT$-violating signals in the double beta decay spectrum of $^{136}\mathrm{Xe}$ has been performed using an exposure $100\text{ }\text{ }\mathrm{kg}\ifmmode\cdot\else\textperiodcentered\fi{}\mathrm{yr}$ with EXO-200 detector. No significant evidence spectral modification due to isotropic Lorentz-violation was found, a two-sided limit $\ensuremath{-}2.65\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}\text{...
EXO-200 is a single phase liquid xenon detector designed to search for neutrinoless double-beta decay of $^{136}$Xe. Here we report on various Majoron-emitting modes based 100 kg$\cdot$yr exposure A lower limit $T^{^{136}Xe}_{1/2} >1.2 \cdot 10^{24}$ yr at 90% C.L. the half-life spectral index = 1 Majoron was obtained, corresponding constraint Majoron-neutrino coupling constant $|< g^{M}_{ee} >|<$ (0.8-1.7)$\cdot$10$^{-5}$.
Alpha decays in the EXO-200 detector are used to measure fraction of charged $^{218}\text{Po}$ and $^{214}\text{Bi}$ daughters created from $\ensuremath{\alpha}$ $\ensuremath{\beta}$ decays, respectively. $^{222}\text{Rn} \ensuremath{\alpha}$ liquid xenon (LXe) found produce $^{218}\text{Po}^{+}$ ions $50.3\ifmmode\pm\else\textpm\fi{}3.0%$ time, while remainder atoms neutral. The $^{214}\text{Bi}^{+}$ $^{214}\text{Pb} \ensuremath{\beta}$ LXe is be $76.4\ifmmode\pm\else\textpm\fi{}5.7%$,...
The EXO-200 Collaboration is searching for neutrinoless double $\ensuremath{\beta}$ decay using a liquid xenon (LXe) time projection chamber. This measurement relies on modeling the transport of charge deposits produced by interactions in LXe to allow discrimination between signal and background events. Here we present measurements transverse diffusion constant drift velocity electrons at fields 20 V/cm 615 data. At operating field 380 measures...
The search for neutrinoless double-beta decay (0νββ) requires extremely low background and a good understanding of their sources influence on the rate in region parameter space relevant to 0νββ signal. We report studies various β γ backgrounds liquid-xenon-based EXO-2000νββ experiment. With this work we try better understand location strength specific compare conclusions radioassay results taken before during detector construction. Finally, discuss implications these EXO-200 as well...
Dynamic Nuclear Polarization (DNP) is a powerful suite of techniques that deliver multifold signal enhancements in nuclear magnetic resonance (NMR) and MRI. The generated athermal spin states can also be exploited for quantum sensing as probes many-body physics. Typical DNP methods require the use cryogens, large fields, high power microwave excitation, which are expensive unwieldy. Nanodiamond particles, rich Nitrogen-Vacancy (NV) centers, have attracted attention alternative agents because...
As neutrinoless double-beta decay experiments become more sensitive and intrinsic radioactivity in detector materials is reduced, previously minor contributions to the background must be understood eliminated. With this mind, cosmogenic backgrounds have been studied with EXO-200 experiment. Using TPC, muon flux (through a flat horizontal surface) underground at Waste Isolation Pilot Plant (WIPP) has measured {\Phi} = 4.07 $\pm$ 0.14 (sys) 0.03 (stat) $\times$ $10^{-7}$cm$^{-2}$ s$^{-1}$,...
We have experimentally determined the production rate of $^{39}$Ar and $^{37}$Ar from cosmic ray neutron interactions in argon at sea level. Understanding these rates is important for argon-based dark matter experiments that plan to utilize extracted deep underground because it imperative know what ingrowth will be during production, transport, storage argon. These measurements also allow prediction concentrations atmosphere which can used determine presence other sources isotopes. Through...
We present a search for electron-recoil signatures from the charged-current absorption of fermionic dark matter using EXO-200 detector. report an average background rate $6.8\ifmmode\times\else\texttimes\fi{}{10}^{4}\text{ }\text{ }\mathrm{cts}\text{ }{\mathrm{kg}}^{\ensuremath{-}1}\text{ }{\mathrm{yr}}^{\ensuremath{-}1}\text{ }{\mathrm{keV}}^{\ensuremath{-}1}$ above 4 MeV and find no statistically significant excess over our projection. Using total $^{136}\mathrm{Xe}$ exposure 234.1 kg yr,...
A search for Majoron-emitting modes of the neutrinoless double-beta decay $^{136}$Xe is performed with full EXO-200 dataset. This dataset consists a total exposure 234.1 kg$\cdot$yr, and includes data detector upgrades that have improved energy threshold relative to previous searches. lower limit T$_{1/2}^{\rm{^{136}Xe}}>$4.3$\cdot$10$^{24}$ yr at 90\% C.L. on half-life spectral index $n=1$ Majoron was obtained, factor 3.6 more stringent than from EXO-200, corresponding constraint...
The production of $^{3}$H, $^{7}$Be, and $^{22}$Na by interactions cosmic-ray particles with silicon can produce radioactive backgrounds in detectors used to search for rare events. Through controlled irradiation CCDs wafers a neutron beam that mimics the spectrum, followed direct counting, we determined rate from neutrons at sea level is ($112 \pm 24$) atoms/(kg day) ($8.1 1.9 $) ($43.0 7.1 $^{22}$Na. Complementing these results current best estimates activation cross sections other than...
Searches for double beta decay of $^{134}$Xe were performed with EXO-200, a single-phase liquid xenon detector designed to search neutrinoless $^{136}$Xe. Using an exposure $29.6\text{ kg}\!\cdot\!\text{yr}$, the lower limits $\text{T}_{1/2}^{2\nu\beta\!\beta}>8.7\cdot10^{20}\text{ yr}$ and $\text{T}_{1/2}^{0\nu\beta\!\beta}>1.1\cdot10^{23}\text{ at 90% confidence level derived, corresponding half-life sensitivities $1.2\cdot10^{21}\text{ $1.9\cdot10^{23}\text{ yr}$. These exceed those in...
A search for instability of nucleons bound in $^{136}$Xe nuclei is reported with 223 kg$\cdot$yr exposure the EXO-200 experiment. Lifetime limits 3.3$\times 10^{23}$ and 1.9$\times yrs are established nucleon decay to $^{133}$Sb $^{133}$Te, respectively. These most stringent date, exceeding prior by a factor 9 7,
EXO-200 is a single phase liquid xenon detector designed to search for neutrinoless double-beta decay of $^{136}$Xe the ground state $^{136}$Ba. We report here on two-neutrino first $0^+$ excited state, $0^+_1$, $^{136}$Ba based 100 kg$\cdot$yr exposure $^{136}$Xe. Using specialized analysis employing machine learning algorithm, we obtain 90% CL half-life sensitivity $1.7 \times 10^{24}$ yr. find no statistically significant evidence $2\nu\beta\beta$ resulting in lower limit $T^{2\nu}_{1/2}$...
Presented is a design of mixed signal integrator, consisting traditional analog integrator (op-amp with capacitor in feedback) augmented comparators, logic, counter registers, and precharged that can be switched into, out of, the input integrator. This device integrates analog, but stores results digital. Whenever an voltage equals or exceeds threshold voltage, amount charge equivalent to cleared from feedback register incremented decremented accordingly. With representing one counting...
The Daya Bay reactor antineutrino experiment is designed to make a precision measurement of the neutrino mixing angle θ13, and recently made definitive discovery its non-zero value. It utilizes set eight, functionally identical detectors measure flux spectrum at baselines ∼ 300–2000 m from Ling Ao Nuclear Power Plants. were built in an above-ground facility deployed side-by-side three underground experimental sites near far nuclear reactors. This configuration allows disappearance over...
Generative Adversarial Networks trained on samples of simulated or actual events have been proposed as a way generating large datasets at reduced computational cost. In this work, novel approach to perform the simulation photodetector signals from time projection chamber EXO-200 experiment is demonstrated. The method based Wasserstein Network - deep learning technique allowing for implicit non-parametric estimation population distribution given set objects. Our network real calibration data...
The energy resolution of the EXO-200 detector is limited by electronics noise in measurement scintillation response. Here we present a new technique to extract optimal measurements for signals split across multiple channels presence correlated noise. implementation these techniques improves at neutrinoless double beta decay Q-value from [1.9641 ± 0.0039]% [1.5820 0.0044]%.
We have measured the muon flux and production rate of muon-induced neutrons at a depth 611 m water equivalent. Our apparatus comprises three layers crossed plastic scintillator hodoscopes for tracking incident cosmic-ray muons 760 L gadolinium-doped liquid producing detecting neutrons. The vertical intensity was to be $I_{\mu} = (5.7 \pm 0.6) \times 10^{-6}$ cm$^{-2}$s$^{-1}$sr$^{-1}$. yield in determined $Y_{n} (1.19 0.08 (stat) 0.21 (syst)) 10^{-4}$ neutrons/($\mu\cdot$g$\cdot$cm$^{-2}$)....
The production of radioactive isotopes by interactions cosmic-ray particles with sodium iodide (NaI) crystals can produce backgrounds in detectors used to search for rare events. Through controlled irradiation NaI a neutron beam that matches the spectrum, followed direct counting and fitting resulting spectrum across broad range energies, we determined integrated rate several long-lived radioisotopes. measurements were then extrapolated determine sea-level cosmogenic activation rate,...