A5030104976- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Quantum, superfluid, helium dynamics
- Particle Detector Development and Performance
- Space Technology and Applications
- Radiation Detection and Scintillator Technologies
- Particle physics theoretical and experimental studies
- Laser-Plasma Interactions and Diagnostics
- High-pressure geophysics and materials
- Cold Atom Physics and Bose-Einstein Condensates
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Quantum Chromodynamics and Particle Interactions
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Particle accelerators and beam dynamics
- Electromagnetic Launch and Propulsion Technology
- Astronomy and Astrophysical Research
- High-Velocity Impact and Material Behavior
- Nuclear physics research studies
- Energetic Materials and Combustion
- Nuclear reactor physics and engineering
- CCD and CMOS Imaging Sensors
- Ion-surface interactions and analysis
- Stellar, planetary, and galactic studies
Oak Ridge National Laboratory
2022-2023
Los Alamos National Laboratory
2013-2022
Utah State University
2020-2021
North Carolina State University
2020-2021
California Institute of Technology
2020-2021
Tennessee Technological University
2020-2021
University of Kentucky
2020-2021
Indiana University Bloomington
2020-2021
East Tennessee State University
2020-2021
Los Alamos Medical Center
2009
We report an improved measurement of the free neutron lifetime τ_{n} using UCNτ apparatus at Los Alamos Neutron Science Center. count a total approximately 38×10^{6} surviving ultracold neutrons (UCNs) after storing in UCNτ's magnetogravitational trap over two data acquisition campaigns 2017 and 2018. extract from three blinded, independent analyses by both pairing long short storage time runs to find set replicate measurements performing global likelihood fit all while self-consistently...
The precise value of the mean neutron lifetime, $\tau_n$, plays an important role in nuclear and particle physics cosmology. It is a key input for predicting ratio protons to helium atoms primordial universe used search new beyond Standard Model physics. There 3.9 standard deviation discrepancy between $\tau_n$ measured by counting decay rate free neutrons beam (887.7 $\pm$ 2.2 s) surviving ultracold stored different storage times material trap (878.5$\pm$0.8 s). experiment described here...
A neutron $\ensuremath{\beta}$-decay asymmetry measurement using polarized ultracold neutrons (UCN) determines the correlation between spin of and momentum decay electron. The authors extract ratio weak axial-vector to vector couplings with reduced uncertainties. This new result from first this UCN contributes a benchmark for lattice QCD calculations possibility improved precision on CKM matrix element ${V}_{u\phantom{\rule{0}{0ex}}d}$ $\ensuremath{\beta}$ decay.
The ultracold neutron (UCN) source at Los Alamos National Laboratory (LANL), which uses solid deuterium as the UCN converter and is driven by accelerator spallation neutrons, has been successfully operated for over 10 years, providing to various experiments, first production based on superthermal process. It recently undergone a major upgrade. This paper describes design performance of upgraded LANL source. Measurements cold spectrum density are presented compared Monte Carlo predictions....
We demonstrate that high-Z material can be detected and located in three dimensions using radiographs formed by cosmic-ray muons. Detection of hidden inside large volume ordinary cargo is an important timely task given the danger associated with illegal transport uranium heavier elements. Existing radiography techniques are inefficient for shielded material, often expensive involve radiation hazards, real perceived. recently demonstrated muons [K. N. Borozdin et al., Nature (London) 422, 277...
Ultra-cold neutrons (UCN), with energies low enough to be confined by the Fermi potential in material bottles, are playing an increasing role measurements of fundamental properties neutron. The ability manipulate UCN guides and magnetic fields, gravity can lead experiments lower systematic errors than have been obtained cold neutron beams. densities provided existing reactor sources limit these experiments. promise much higher from solid deuterium has led proposed facilities coupled both...
Over 120 million vehicles enter the United States each year. Many are capable of transporting hidden nuclear weapons or material. Currently deployed X-ray radiography systems limited because they cannot be used on occupied and energy dose too low to penetrate many cargos. We present a new technique that overcomes these limitations by obtaining tomographic images using multiple scattering cosmic radiation as it transits vehicle. When coupled with passive detection, muon interrogation could...
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 present the first measurements of survival time ultracold neutrons (UCNs) in solid deuterium (SD2). This critical parameter provides a fundamental limitation to effectiveness superthermal UCN sources that utilize ortho-deuterium as source material. These are performed utilizing SD2 coupled spallation neutrons, providing demonstration production this geometry and permitting systematic studies influence thermal up-scatter contamination with para-deuterium on time.
The accuracy of density measurements and position resolution in flash (40 ns) radiography thick objects with 24 Gev/c protons is investigated. A global model fit to step wedge data shown give a good description spanning the periodic table. parameters obtained from are used predict transmission through French Test Object (FTO), test object nested spheres, precision better than 1%. Multiple trials have been show that systematic errors less 2%. Absolute agreement between average radiographic...
This article describes the design and performance of a magnifying magnetic-lens system designed, built, commissioned at Los Alamos National Laboratory (LANL) for 800 MeV flash proton radiography. The technique radiography has been developed LANL to study material properties under dynamic loading conditions through analysis time sequences radiographs. requirements this growing experimental program have resulted in need improvements spatial radiographic resolution. To meet these needs, new...
The Ultracold Neutron Asymmetry (UCNA) experiment was designed to measure the $\beta$-decay asymmetry parameter, $A_0$, for free neutron decay. In experiment, polarized ultracold neutrons are transported into a decay trap, and their electrons detected with $\approx 4\pi$ acceptance two detector packages which provide position energy reconstruction. also has sensitivity $b_{n}$, Fierz interference term in rate. this work, we determine $b_{n}$ from dependence of $A_0$ using data taken during...
Direct density measurements were made from shock-loaded aluminum and copper samples by combining plate-impact experiments with proton radiography at the Los Alamos Neutron Science Center. Flyer plates accelerated using a 40 mm bore powder gun to create shock wave in sample. The sample material was then interrogated real time facility. increase behind front causes measurable change transmission of protons through sample, which can be quantified as value material. Hugoniot values calculated...
We present a new phenomenology for burn propagation inside thermal explosion based on dynamic radiography. Radiographic images were obtained of an aluminum cased solid cylindrical sample plastic bonded formulation octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine. The observed is ignition followed by cracking in the accompanied radially symmetric front increasing proton transmission. This further increase transmission through sample, ending after approximately $100\text{ }\text{...
A measurement of the production ultracold neutrons from velocity-selected cold on gaseous and solid deuterium targets is reported. The expected energy dependence for two-particle collisions with well defined neutron Maxwell-Boltzmann distributed molecular velocities found gas target. target data agree in shape phonon density-of-states curve provide strong evidence model including multiphonon excitations.
Reaction and total cross sections for ${\mathrm{\ensuremath{\pi}}}^{+}$ ${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$ on targets of $^{2}\mathrm{H}$, $^{6}\mathrm{Li}$, C, Al, Si, S, Ca have been measured beam energies from 42 to 65 MeV. The are proportional the target mass at 50 MeV, consistent with transparency these projectiles. compared theoretical calculations. \textcopyright{} 1996 American Physical Society.
An application of nuclear physics, a facility for using protons flash radiography, has been developed at the Los Alamos Neutron Science Center (LANSCE). Protons have proven far superior to high energy x-rays radiography because their long mean free path, good position resolution, and low scatter background. Although this is primarily used studying very fast phenomena such as explosive driven experiments, it finding increasing other fields, tomography static objects, phase changes in...
We report proton transmission images obtained subsequent to the laser assisted thermal ignition of a sample PBX 9501 (a plastic bonded formulation explosive nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)). describe technique as means synchronize non-linear event while preserving post-ignition behavior. have dynamic at two spatial magnifications and viewed both radial transverse axis solid cylindrical encased in aluminum. Images been with 3 15 μs temporal resolution...