A5085037385- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Radiation Detection and Scintillator Technologies
- Radiation Therapy and Dosimetry
- Quantum Information and Cryptography
- Nuclear physics research studies
- Laser-Plasma Interactions and Diagnostics
- Atomic and Subatomic Physics Research
- Quantum Mechanics and Applications
- High-pressure geophysics and materials
- Quantum Computing Algorithms and Architecture
- Graphite, nuclear technology, radiation studies
- Magnetic confinement fusion research
- Atomic and Molecular Physics
- Fusion materials and technologies
- Quantum, superfluid, helium dynamics
- Particle accelerators and beam dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Superconducting Materials and Applications
- Orbital Angular Momentum in Optics
- Particle Detector Development and Performance
- Quantum Chromodynamics and Particle Interactions
- Nuclear Materials and Properties
- Advanced NMR Techniques and Applications
- Particle physics theoretical and experimental studies
Los Alamos National Laboratory
2012-2024
University of Toronto
2024
QuantuMDx (United Kingdom)
2021-2023
Brookhaven National Laboratory
2006
RIKEN BNL Research Center
2006
Lawrence Livermore National Laboratory
2003
Executive Office of the President
2000
University of California Office of the President
2000
National Institute of Standards and Technology
2000
University of California System
1999
A working free-space quantum key distribution system has been developed and tested over an outdoor optical path of $\ensuremath{\sim}1\mathrm{km}$ at Los Alamos National Laboratory under nighttime conditions. Results show that can provide secure real-time between parties who have a need to communicate secretly. Finally, we examine the feasibility surface satellite distribution.
We have completed a new set of total cross section measurements 31 elements and isotopes spanning the periodic table from A=1 to 238. employed same technique as in Finley et al. [Phys. Rev. C 47, 237 (1993)] with refinements intended allow on separated improved systematic error control. The goal measurement was 1% statistical accuracy energy bins errors less than 1%. This achieved for all but thinnest samples. Stringent checks this resulted reassignment uncertainties neutron sections...
A neutron imaging diagnostic has recently been commissioned at the National Ignition Facility (NIF). This new system is an important tool for inertial fusion studies NIF measuring size and shape of burning DT plasma during ignition stage Inertial Confinement Fusion (ICF) implosions. The technique utilizes a pinhole aperture, placed between source detector. detection measures two dimensional distribution neutrons passing through pinhole. designed to collect images times. long flight path this...
DT neutron yield (Y(n)), ion temperature (T(i)), and down-scatter ratio (dsr) determined from measured spectra are essential metrics for diagnosing the performance of inertial confinement fusion (ICF) implosions at National Ignition Facility (NIF). A suite neutron-time-of-flight (nTOF) spectrometers a magnetic recoil spectrometer (MRS) have been implemented in different locations around NIF target chamber, providing good implosion coverage complementarity required reliable measurements Y(n),...
Quantum key distribution (QKD) has been demonstrated over a point-to-point 1.6-km atmospheric optical path in full daylight. This record transmission distance brings QKD step closer to surface-to-satellite and other long-distance applications.
Pulsed-beam time-of-flight techniques are used in a transmission measurement with continuous spectrum of neutrons to determine neutron total cross sections good precision up 600 MeV. Neutrons produced by spallation the 800 MeV proton beam from Los Alamos Meson Physics Facility accelerator incident on thick, heavily shielded tungsten target at Weapons Neutron Research facility National Laboratory. Transmission measurements were completed for fifteen elements...
Abstract Quantum cryptography is a new method for secret communications offering the ultimate security assurance of inviolability law nature. In this paper we shall describe theory quantum cryptography, its potential relevance and development prototype system at Los Alamos, which utilizes phenomenon single-photon interference to perform over an optical fibre link.
Abstract The secure distribution of the secret random bit sequences known as 'key' material, is an essential precursor to their use for encryption and decryption confidential communications. Quantum cryptography a new technique key with single-photon transmissions: Heisenberg's uncertainty principle ensures that adversary can neither successfully tap transmissions, nor evade detection (eavesdropping raises error rate above threshold value). We have developed experimental quantum systems...
AbstractDifferential (p,xn) cross sections, d2σ/dΩ dEn, from thin targets and absolute neutron yields stopping-length at angles of 7.5, 30, 60, 150 deg for the 113-MeV proton bombardment elemental beryllium, carbon, aluminum, iron, depleted uranium are measured. Additional cross-section measurements reported oxygen, tungsten, lead. Time-of-flight techniques used to identify discriminate against backgrounds determine energy spectrum. Comparisons experimental data with intranuclear-cascade...
Precision relative differential cross sections for the scattering of neutrons from helium were measured at 22 neutron energies between 0.2 and 7.0 MeV. The measurements made by observing energy distribution recoiling nuclei in a high-pressure helium-gas scintillation counter irradiated monoenergetic neutrons. An analysis data was terms phase shifts. could be satisfactorily represented without use partial waves higher than $l=1$. dependence shifts found to good agreement with that predicted...
Experimental observations of plasma behavior in a novel formation chamber are reported. results reasonable agreement with two-dimensional magnetohydrodynamic computations suggesting that the could subsequently be adiabatically compressed by magnetically driven pusher to yield 1 GJ fusion energy. An explosively helical flux compression generator mated unique closing switch/opening switch combination delivered 2.7 MA, 347 μs magnetization current and an additional 5 2.5 electrical pulse...
The $\mathrm{np}$ total cross section has been measured from 40 to 770 MeV with good statistical precision and better than 1% energy resolution. No evidence is seen for narrow resonances areas greater 5 mb or the $I=0$, $^{1}F_{3}$ state reported by other authors. From 200 700 present results are as much 6% lower previous data.
First results from the analysis of neutron image data collected on implosions cryogenically layered deuterium-tritium capsules during 2011-2012 National Ignition Campaign are reported. The span a variety experimental designs aimed at increasing stagnation pressure central hotspot and areal density surrounding fuel assembly. Images neutrons produced by deuterium–tritium fusion reactions in presented, as well images that scatter dense compared with 1D 2D model predictions, consistency checked...
A working free-space quantum key distribution (QKD) system has been developed and tested over a 205-m indoor optical path at Los Alamos National Laboratory under fluorescent lighting conditions. Results show that QKD can provide secure real-time between parties who have need to communicate secretly.
Differential (p,xn) cross sections are measured for 800-MeV protons incident on thin targets of depleted uranium and natural beryllium, boron, carbon, nitrogen, oxygen, aluminum, iron, cadmium, tungsten, lead. Measurements neutron energies from 0.3 to 800 MeV made at angles of30, 60, 120, 150 deg. Time-of-flight techniques used determine the energy spectra, particular effort is identify discriminate against background contributions. Comparisons experimental data with calculations using...
We report a direct measurement of temperature in shocked metal using Doppler broadening neutron resonances. The 21.1-eV resonance 182W was used to measure the molybdenum approximately 63 GPa. An explosively launched aluminum flyer produced planar shock target that contained 1-mm thick layer doped with 1.7 at. %(182)W. A single pulse, containing resonant neutrons less than 1 mus duration, probed material. Fits time-of-flight data were determine molybdenum.
Differential (p,xn) cross sections, d2σ/dΩ dEn, from thin targets of beryllium, carbon, oxygen, aluminum, iron, lead, and 238U for 256-MeV protons are measured. Time-of-flight techniques used to identify discriminate against backgrounds determine the neutron energy spectrum. Comparison experimental data with intranuclear-cascade evaporation-model calculations using HETC code showed discrepancies as much a factor 7, notably at 7.5 150 deg.
AbstractAbstractAbsolute neutron yields at angles of 30, 60, 120, and 150 deg for the 256-MeV proton bombardment elemental carbon, aluminum, iron depleted uranium were measured. We used time-of-flight techniques to identify discriminate against backgrounds determine energy spectrum. Comparison experimental with intranuclear cascade evaporation model calculations using HETC ISABEL codes showed very good agreement over entire range except deg.
The National Ignition Facility (NIF) is scheduled to begin deuterium-tritium (DT) shots possibly in the next several years. One of important diagnostics understanding capsule behavior and guide changes Hohlraum illumination, design, geometry will be neutron imaging both primary 14 MeV neutrons lower-energy downscattered 6–13 range. system (NIS) described here, which we are currently building for use on NIF, uses a precisely aligned set apertures near target form images segmented...
The dense plasma focus (DPF) has long been considered a compact source for pulsed neutrons and traditionally optimized the total neutron yield. In this paper, we describe efforts to optimize DPF short-pulse applications by introducing reentrant cathode at end of coaxial gun. resulting pulse widths are reduced an average 21±9% from traditional long-drift design. Pulse yields achieved deuterium-tritium fusion 2 MA 61.8±30.7 ns FWHM 1.84±0.49×1012 per shot. Simulations were conducted...
The joint LANL/LLNL nuclear imaging team has acquired the first gamma-ray images of inertial confinement fusion implosions at National Ignition Facility. image provides crucial information to help characterize inertially confined fuel and ablator assembly stagnation, that would be difficult acquire from neutron or x-ray observations. Gamma visualizes both gamma radiation emitted directly in deuterium–tritium (DT) reactions as well rays produced when DT neutrons scatter inelastically on...
Free-space quantum key distribution (QKD), more popularly know as cryptography, uses single-photon free-space optical communications to distribute the secret keys required for secure communications. At Los Alamos National Laboratory we have demonstrated a fully automated system that is capable of operations at any time day over horizontal range several kilometers. This has proven technology operation from spacecraft ground, opening up possibility QKD between group users anywhere on Earth....