A5034865212- Nuclear physics research studies
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Quantum Chromodynamics and Particle Interactions
- Atomic and Molecular Physics
- Quantum Mechanics and Non-Hermitian Physics
- Crystallography and Radiation Phenomena
- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Quantum chaos and dynamical systems
- Statistical Mechanics and Entropy
- High-pressure geophysics and materials
- Advanced NMR Techniques and Applications
- Advanced Chemical Physics Studies
- Nuclear Materials and Properties
- Numerical methods in inverse problems
- Spectral Theory in Mathematical Physics
- Atomic and Subatomic Physics Research
- Geomagnetism and Paleomagnetism Studies
- Radiation Detection and Scintillator Technologies
- Nonlinear Waves and Solitons
- Superconducting Materials and Applications
- Electron and X-Ray Spectroscopy Techniques
- Quantum, superfluid, helium dynamics
- Nonlinear Photonic Systems
TU Wien
2014-2024
Lawrence Livermore National Laboratory
2019
International Atomic Energy Agency
2019
University of South Africa
1992-2003
University of Vienna
1995
Harvard University
1992
The University of Melbourne
1991
Max Planck Institute for Nuclear Physics
1985
University of Tübingen
1982
Universities Austria
1980
Abstract The joint evaluated fission and fusion nuclear data library 3.3 is described. New evaluations for neutron-induced interactions with the major actinides $$^{235}\hbox {U}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow /><mml:mn>235</mml:mn></mml:msup><mml:mtext>U</mml:mtext></mml:mrow></mml:math> , $$^{238}\hbox /><mml:mn>238</mml:mn></mml:msup><mml:mtext>U</mml:mtext></mml:mrow></mml:math> $$^{239}\hbox {Pu}$$...
We propose to apply Ramsey's method of separated oscillating fields the spectroscopy quantum states in gravity potential above a vertical mirror. This allows precise measurement mechanical phaseshifts Schrödinger wave packet bouncing off hard surface gravitational field earth. Measurements with ultra-cold neutrons will offer sensitivity Newton's law or hypothetical short-ranged interactions, which is about 21 orders magnitude below energy scale electromagnetism.
New limits are obtained, several orders of magnitude lower than previously reported, for coupling constant versus mass the exchange hypothetical light bosons to baryons in range 20 MeV>${\mathit{m}}_{\mathit{B}}$${\mathit{c}}^{2}$>20 \ensuremath{\mu}eV (interaction 10 fm${\mathit{R}}_{\mathrm{int}}$1 cm). These obtained from neutron-nucleus scattering below keV and neutron optics data. This closes gap between high-energy physics macroscopic fifth-force experiments searches new interactions....
The evaluation of nuclear reaction data within the resolved resonance regime relies on phenomeno-logical R-matrix analyses. In absence quantitatively reliable microscopic models phenomenological manages to reproduce experiment at high accuracy especially in with a limited number parameters while unitarity constraints and sum rules are automatically met. However, due non-trivial mapping between fitting observables as well interference effects, standard only loosely correlate observed...
The knowledge of nuclear reaction data is an important requisite for the development and advances in technologies, but also several fields basic sciences such as astrophysics, medicine material sciences. Nuclear evaluation aims to reveal best reactions combining available experimental data, theoretical mathematical constraints. A brief introduction into concept Bayesian techniques given importance proper inclusion correlations between experiments discussed. An aspect generation reliable...
The status of the Joint Evaluated Fission and Fusion file (JEFF) is described.JEFF-3.1 comprises a significant update actinide evaluations, materials evaluations that have emerged from various European nuclear data projects, activation library JEFF-3.1/A, decay fission yield sub-libraries, fusion-related files EFF project.The revisions were motivated by availability new measurements, modelling capabilities trends integral experiments.Validations been performed, mainly for criticality,...
A statistically consistent method for the inclusion of so-called model defects into Bayesian evaluation methods based on extensive modeling is presented. The uses Gaussian processes to define a-priori probability distributions possible defects. particular importance proper differential data, i.e. angle-differential cross sections and spectra ejectiles. successfully applied a simple realistic example which clearly shows impact in simultaneous angle-integrated sections.
A method to obtain the crystal potential from intensities of diffracted beams in high-energy electron diffraction is proposed. It based on a series measurements for specific well determined orientations incident beam, which determine moduli all elements scattering matrix. Using unitarity and form matrix (including symmetries), an overdetermined set non-linear equations obtained these data. Solution yields required phase information allows determination (projected) by inversion that unique up...
A method to invert the dynamical diffraction of high-energy electrons inside a crystal, which takes into account absorption, is discussed. It shown that, working at fixed energy, projected potentials associated with both elastic and absorptive scattering can be uniquely obtained from matrix. Inversion possible for any principal orientation incident beam. Model examples are given.
The manifestation of pseudospin symmetry in proton-nucleus scattering is discussed. Constraints on the pseudospin-symmetry violating amplitude are given, which require as input cross section and polarization data, but no measurements spin-rotation function. Application these constraints to $p\text{\ensuremath{-}}^{58}\mathrm{Ni}$ $p\text{\ensuremath{-}}^{208}\mathrm{Pb}$ data laboratory energy range $200\phantom{\rule{0.3em}{0ex}}\text{MeV}--800\phantom{\rule{0.3em}{0ex}}\text{MeV}$ reveals...
An exact determination of the size pseudospin symmetry-violating part nucleon-nucleus scattering amplitude from observables is presented. The approximation recently used by Ginocchio turns out to underestimate violation symmetry. Nevertheless conclusion a modestly broken symmetry in proton-${}^{208}\mathrm{Pb}$ at ${E}_{L}=800$ MeV remains valid.
A wide class of Darboux transformations a Sturm-Liouville equation providing unified treatment exactly solvable models in quantum scattering theory is considered systematically. classification given and the relations between standard inverse procedures for radial Schrodinger including matrix method Newton-Sabatier are studied. In particular, definitions, properties generalizations associated with Marchenko-type integral equations studied detail.
The experimental elastic scattering cross section is inverted into an optical potential using a rational parametrization of the function. A regularized error analysis carried out. method successfully applied to system \ensuremath{\alpha}${\mathrm{\ensuremath{-}}\mathrm{}}^{40}$Ca at 104 MeV.
A quantitatively reliable knowledge of several reaction cross sections light nuclear systems is an important prerequisite for developments in technology, but also fields science. At present the situation evaluated section data nuclei not fully satisfactory because most are exclusively based on experimental and thus limited energy included channels. The main reason absence a (semi-)microscopic description reactions with predictive power. Therefore, these R-matrix analyses widely performed to...
The retrieval of a unique crystal potential from the scattering matrix {\cal S} in high-energy transmission electron diffraction is discussed. It shown that, general, data taken at single orientation are not sufficient to determine all elements S}. Additional measurements with tilted incident beam required for determination whole matrix. An algorithm extraction measured energy and thickness presented. limiting case thin crystals Several examples simulated considered.
The occurrence of unexpected mean values in statistical analyses experimental data, known as Peelle’s pertinent puzzle nuclear data evaluation, is revisited. It shown terms Bayesian statistics, it not caused exclusively by nonlinearities but due to improper estimates covariance matrices experiments. Applying the correct matrix leads exact posterior expectation value and variance for an arbitrary number uncorrelated measurement points that are normalized with same quantity.