W. E. Sondheim
A5083434000- Particle Detector Development and Performance
- Particle physics theoretical and experimental studies
- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
- Dark Matter and Cosmic Phenomena
- Nuclear Physics and Applications
- High-Energy Particle Collisions Research
- Radiation Detection and Scintillator Technologies
- Particle Accelerators and Free-Electron Lasers
- Radiation Effects in Electronics
- Quantum Chromodynamics and Particle Interactions
- Electron and X-Ray Spectroscopy Techniques
- Silicon Carbide Semiconductor Technologies
- Nuclear physics research studies
- Atomic and Molecular Physics
- Isotope Analysis in Ecology
- Advanced Semiconductor Detectors and Materials
- Advanced NMR Techniques and Applications
- Archaeology and ancient environmental studies
- Advanced Data Storage Technologies
- Plasma Diagnostics and Applications
- Advanced Frequency and Time Standards
- Advanced Chemical Physics Studies
- Advancements in Semiconductor Devices and Circuit Design
- Astrophysics and Cosmic Phenomena
Los Alamos National Laboratory
2012-2024
University of Rochester
1977
Mass spectrometric methods have long been suggested as ways of measuring (14)C/(12)C ratios for carbon dating. One problem has to distinguish between (14)N and (14)C. With negative ions a tandem electrostatic accelerator, the background is virtually absent fewer than three (14)C atoms in 10(16) (12)C easily measured.
This paper describes the operation of Coherent CAPTAIN-Mills (CCM) detector located at Los Alamos Neutron Science Center National Laboratory. CCM is a 10-ton liquid argon 20 meters from high flux neutron/neutrino source and designed to search for sterile neutrinos (${\ensuremath{\nu}}_{s}$'s) light dark matter (LDM). An engineering run was performed in fall 2019 study characteristics CCM120 by searching coherent scattering signals consistent with ${\ensuremath{\nu}}_{s}$'s LDM resulting...
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A new measurement of the neutron $β$-decay asymmetry $A_0$ has been carried out by UCNA collaboration using polarized ultracold neutrons (UCN) from solid deuterium UCN source at Los Alamos Neutron Science Center (LANSCE). Improvements in experiment have led to reductions both statistical and systematic uncertainties leading $A_0 = -0.11954(55)_{\rm stat.}(98)_{\rm syst.}$, corresponding ratio axial-vector vector coupling $λ\equiv g_A/g_V -1.2756(30)$.
In this paper, we describe the performance of Los Alamos spallation-driven solid-deuterium ultra-cold neutron (UCN) source. Measurements cold flux, very low energy production rate, and UCN rates density at exit from biological shield are presented compared to Monte Carlo predictions. The compare well with predictions code MCNPX agree our custom code. source is shown perform as modeled. maximum delivered 52(9) UCN/cc a solid deuterium volume ∼1500 cm3.
A cryogenic apparatus is described that enables a new experiment, nEDM@SNS, with major improvement in sensitivity compared to the existing limit search for neutron Electric Dipole Moment (EDM). This uses superfluid 4He produce high density of Ultra-Cold Neutrons (UCN) which are contained suitably coated pair measurement cells. The be operated at Spallation Neutron Source Oak Ridge National Laboratory, polarized 3He from an Atomic Beam injected into and transported cells where it serves as...
The proposed Electron-Ion Collider (EIC) will utilize high- luminosity high-energy electron+proton ( e + p ) and electron+nucleus A collisions to solve several fundamental questions including searching for gluon saturation studying the proton/nuclear structure. Complementary ongoing EIC project detector technical prototype carried out by ePIC collaboration, a Depleted Monolithic Active Pixel Sensor (i.e., MALTA2) based fast timing silicon tracking (FMT) has been provide additional hits track...
We present a detailed report of measurement the neutron $\beta$-asymmetry parameter $A_0$, parity-violating angular correlation between spin and decay electron momentum, performed with polarized ultracold neutrons (UCN). UCN were extracted from pulsed spallation solid deuterium source via transport through 7-T magnetic field. The then transported an adiabatic-fast-passage spin-flipper field region, prior to storage in cylindrical volume situated within 1-T $2 \times 2\pi$ solenoidal...
We report the first results of a search for leptophobic dark matter (DM) from Coherent-CAPTAIN-Mills (CCM) liquid argon (LAr) detector. An engineering run with 120 photomultiplier tubes (PMTs) and 17.9×10^{20} protons on target (POT) was performed in fall 2019 to study characteristics CCM The operation this 10-ton detector strictly light based threshold 50 keV used coherent elastic scattering off nuclei detect DM. Despite only 1.5 months accumulated luminosity, contaminated LAr, nonoptimized...
We show results from the Coherent CAPTAIN Mills (CCM) 2019 engineering run which begin to constrain regions of parameter space for axion-like particles (ALPs) produced in electromagnetic particle showers an 800 MeV proton beam dump, and further investigate sensitivity ongoing data-taking campaigns CCM200 upgraded detector. Based on beam-on background estimates run, we make realistic extrapolations reduction based expected shielding improvements, reduced width, analysis-based techniques...
The radiation damage resulting from the large particle fluences predicted at Superconducting Super Collider induces significant leakage currents in Si detectors. In order to limit these currents, detectors are operated reduced temperatures ( approximately 0 degrees C). Results presented of a study temperature effects on both initial and long-term annealing that PIN Depletion voltage results reported. exposed 10/sup 14//cm/sup 2/ 650-MeV protons. Very pronounced dependences observed.< <ETX...
The proposed high-energy and high-luminosity Electron-Ion Collider (EIC) will provide one of the cleanest environments to precisely determine nuclear parton distribution functions (nPDFs) in a wide $x$-$Q^{2}$ range. Heavy flavor production at EIC provides access nPDFs poorly constrained high Bjorken-$x$ region, allows us study quark gluon fragmentation processes, constrains energy loss cold matter. Scientists Los Alamos National Laboratory are developing new physics program heavy...
We have measured $\ensuremath{\alpha}$ + $^{12}\mathrm{C}$ total reaction cross sections (${\ensuremath{\sigma}}_{R}$) at ${E}_{\mathrm{lab}}=94 \mathrm{and} 173$ MeV/N using the attenuation method. Our data indicate a decreasing ${\ensuremath{\sigma}}_{R}(E)$ intermediate incident energies. These results, along with existing measurements, are in quantitative agreement theoretical predictions for which based on nucleon-nucleon sections.NUCLEAR REACTIONS Attenuation measurements of MeV/N.
Received 10 November 2010DOI:https://doi.org/10.1103/PhysRevLett.105.219903© 2010 The American Physical Society
The study of neutron cross sections for elements used as efficient ``absorbers'' ultracold neutrons (UCN) is crucial many precision experiments in nuclear and particle physics, cosmology gravity. In this context, ``absorption'' includes both the capture upscattering to energies above UCN energy region. available data, especially hydrogen, do not agree between themselves or with theory. report we describe measurements performed at Los Alamos National Laboratory facility vanadium hydrogen...
Novel experimental techniques are required to make the next big leap in neutron electric dipole moment sensitivity, both terms of statistics and systematic error control. The nEDM experiment at Spallation Neutron Source (nEDM@SNS) will implement scheme Golub & Lamoreaux [Phys. Rep., 237, 1 (1994)]. unique properties combining polarized ultracold neutrons, 3 He, superfluid 4 He be exploited provide a sensitivity ∼ 10 −28 e · cm. Our cryogenic apparatus deploy two small (3 L) measurement...
It is generally accepted that the main cause of ultracold neutron (UCN) losses in storage traps upscattering to thermal energy range by hydrogen adsorbed on surface trap walls. However, data which this conclusion based are poor and contradictory. Here we report a measurement, performed at Los Alamos National Laboratory UCN source, average flux upscattered neutrons after interaction with bound semicrystalline polymer PMP (trade name TPX), [C${}_{6}$H${}_{12}$]${}_{n}$. Our analysis, mcnp code...
Received 3 November 2017DOI:https://doi.org/10.1103/PhysRevC.96.059901©2017 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBeta decayElectroweak interactionElectroweak interactions in nuclear physicsExtensions of fermion sectorNeutron physicsParticle decaysParticle interactionsPhysical SystemsNeutronsParticles & FieldsNuclear PhysicsAccelerators Beams
The proposed Electron-Ion Collider (EIC) will utilize high-luminosity high-energy electron+proton ($e+p$) and electron+nucleus ($e+A$) collisions to solve several fundamental questions including searching for gluon saturation studying the proton/nuclear structure. Complementary ongoing EIC project detector technical prototype carried out by ePIC collaboration, a Depleted Monolithic Active Pixel Sensor (i.e., MALTA2) based fast timing silicon tracking (FMT) has been provide additional hits...