A5078065728- Nuclear physics research studies
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Quantum Chromodynamics and Particle Interactions
- Astronomical and nuclear sciences
- Advanced NMR Techniques and Applications
- Nuclear reactor physics and engineering
- Muon and positron interactions and applications
- Particle accelerators and beam dynamics
- Advanced Chemical Physics Studies
- Superconducting Materials and Applications
- Particle physics theoretical and experimental studies
- High-Velocity Impact and Material Behavior
- X-ray Spectroscopy and Fluorescence Analysis
- Rare-earth and actinide compounds
- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
- Radiation Detection and Scintillator Technologies
- Boron Compounds in Chemistry
- Structural Response to Dynamic Loads
- Radiation Therapy and Dosimetry
- Graphene research and applications
- High-Energy Particle Collisions Research
- nanoparticles nucleation surface interactions
- Electromagnetic Launch and Propulsion Technology
Oak Ridge National Laboratory
2023
Sandia National Laboratories
2023
Wabash College
2010-2022
Los Alamos National Laboratory
1979-2020
University of York
2007-2018
University of Liverpool
2018
Stanford University
2015
University of California, Los Angeles
2009
George Mason University
2003-2007
Queen's University Belfast
2007
The energies and $B({E2;0}_{\mathrm{g}.\mathrm{s}.}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})$ values for the lowest ${J}^{\ensuremath{\pi}}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2}^{+}$ states in neutron-rich radioactive nuclei ${}^{38,40,42}\mathrm{S}$ ${}^{44,46}\mathrm{Ar}$ were measured via intermediate-energy Coulomb excitation. results ${}^{40,42}\mathrm{S}$ provide first evidence of moderate deformation near $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}28$, while...
The decay energy spectrum for neutron unbound states in 24O (Z=8, N=16) has been observed the first time. resonance of lowest lying state, interpreted as 2+ level, at a above 600 keV. resulting excitation level 4.7 MeV, supplies strong evidence that is doubly magic nucleus. data also consistent with presence second excited state around 5.33 MeV which can be 1+ level.
The neutron unbound ground state of (25)O (Z=8, N=17) was observed for the first time in a proton knockout reaction from (26)F beam. A single resonance found invariant mass spectrum corresponding to decay energy 770_+20(-10) keV with total width 172(30) keV. N=16 shell gap established be 4.86(13) MeV by difference between nu1s(1/2) and nu0d(3/2) orbitals. separation energies agree calculations universal sd model interaction. This interaction incorrectly predicts an (26)O that is bound...
We have measured the longitudinal momentum distribution of ${}^{18}\mathrm{C}$, ${}^{17}\mathrm{C}$, and ${}^{16}\mathrm{C}$ after one-neutron breakup $^{19}C$, respectively, using A1200 fragment separator as an energy-loss spectrometer. The observed narrow width $44.3\ifmmode\pm\else\textpm\fi{}5.9\mathrm{MeV}/c$ for ${}^{18}\mathrm{C}$ fragments indicates that ${}^{19}\mathrm{C}$ is a new example halo, so far heaviest ever observed. consequences obtained results on structure three isotopes...
We have measured the parallel momentum distributions of outcoming fragments in one-neutron breakup odd-mass carbon isotopes ${}^{19,17,15}\mathrm{C}$ and ${}^{14}\mathrm{B}$. Owing to their low neutron separation energies, study these nuclei is particular interest regarding appearance halo phenomenon. Discrepancies between experiment theory observed for ${}^{15}\mathrm{C}$ ${}^{14}\mathrm{B}$ indicate that halos are not as prominent ${}^{11}$Be or ${}^{11}$Li, core excitations start playing...
Fusion cross sections were measured for the exotic proton-halo nucleus ⁸B incident on a ⁵⁸Ni target at several energies near Coulomb barrier. This is first experiment to report fusion of nucleus. The resulting excitation function shows striking enhancement with respect expectations normal projectiles. Evidence presented that sum and breakup yields saturates total reaction section.
Collective transverse flow of nuclear matter was measured as a function the ratio neutrons to protons ( $N/Z$) interacting system for first time. The collisions three isotopically pure beams $A\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}58\mathrm{nuclei}$ with two $A\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}58\mathrm{targets}$ were studied at 55 MeV/nucleon. results variables demonstrate sensitivity transport models elementary aspects nucleon-nucleon collisions.
The energy at which collective transverse flow in the reaction plane disappears, balance ${E}_{\mathrm{bal}}$, is found to depend on isospin of system using reactions ${}^{58}\mathrm{Fe}{+}^{58}\mathrm{Fe}$ and ${}^{58}\mathrm{Ni}{+}^{58}\mathrm{Ni}$. more neutron-rich exhibits higher energies for all measured impact parameters, agreement with predictions a transport model incorporates an dependent mean field in-medium nucleon-nucleon cross sections.
Total reaction cross sections ${\mathrm{\ensuremath{\sigma}}}_{\mathit{R}}$ for $^{8}\mathrm{B}$, $^{12}\mathrm{C}$, and $^{14}\mathrm{N}$ on $^{\mathrm{nat}}\mathrm{Si}$ were measured from about 20 to 60 MeV/nucleon. The $^{12}\mathrm{C}$ compared reasonably well with conventional strong absorption microscopic calculations. Measured $^{8}\mathrm{B}$ slightly larger than those the two heavier nuclei, notably data reproduced by calculations using same matter distribution used explain...
It is shown via a study on $^{26}\mathrm{Mg}$ target that the ($t$,$^{3}\mathrm{He}$) reaction at 115 MeV/nucleon an accurate probe for extracting Gamow-Teller transition strengths. To do so, data are complemented by results from $^{26}\mathrm{Mg}$($^{3}\mathrm{He}$, $t$) 140 allows comparison of $T=2$ analog states excited mirror reactions. Extracted strengths $^{26}\mathrm{Mg}$($t$,$^{3}\mathrm{He}$) and compared with those $^{26}\mathrm{Mg}$($d$,$^{2}\mathrm{He}$)...
Total reaction cross sections, ${\mathrm{\ensuremath{\sigma}}}_{\mathit{R}}$, of 20--60A MeV $^{4,6,8}\mathrm{He}$, $^{6--9,11}\mathrm{Li}$, and $^{10}\mathrm{Be}$ were measured by injecting magnetically separated, focused, monoenergetic, identified secondary beams those projectiles into a Si detector telescope measuring their energy-deposition spectra. These ${\mathrm{\ensuremath{\sigma}}}_{\mathit{R}}$'s, accurate to about 3%, compared with predictions optical, strong absorption,...
The decay structure of the particle-unstable nucleus ${}^{10}\mathrm{Li}$ was studied using method sequential neutron spectroscopy (SNDS) at 0\ifmmode^\circ\else\textdegree\fi{}. energies can be derived from relative velocity spectrum ${}^{9}\mathrm{Li}$ daughter and measured in coincidence. Evidence for low-lying s-wave strength observed with a scattering length $<\ensuremath{-}20\mathrm{fm},$ corresponding to peak energy $<50\mathrm{keV}.$
We have observed a resonance in neutron-fragment coincidence measurements that is presumably the first excited state of $^{23}\mathrm{O}$ at 2.8(1) MeV excitation energy which decays into ground $^{22}\mathrm{O}$. This interpretation consistent with theory. The reaction mechanism supports assignment as $5/{2}^{+}$ hole state. and recently $3/{2}^{+}$ particle advance understanding $^{23}\mathrm{O}$.
Differences in water content and degree of binding the various stem tissues Pelargonium hortorum were observed by magnetic resonance imaging. 1H images obtained with a resolution 100 microns transverse plane slice thickness 1250 microns. It was possible to distinguish principal differences their proton density or apparent spin lattice relaxation time (T1) binding. Measurements made while plant slowly actively transpiring. In transpiring plant, T1 ranged from an average 659 865 ms variation...
Distributions of parallel and transverse momenta for ${}^{7}$Be fragments formed in the breakup ${}^{8}$B have been measured at $41A\mathrm{MeV}$. The ${p}_{\ensuremath{\parallel}}$ distributions are narrow ( $81\ifmmode\pm\else\textpm\fi{}4$ $62\ifmmode\pm\else\textpm\fi{}3\mathrm{MeV}/c$ FWHM Be Au targets, respectively), comparable to those neutron halo nuclei. Reaction mechanisms influence momentum distributions, so they do not directly reflect valence proton wave function. We present...
Energies and atomic structures of asymmetrical $\ensuremath{\Sigma}11[110]$ tilt grain boundaries in copper have been computed using molecular dynamics with an embedded-atom potential. Two interesting effects found: (1) The dissociate into a low-angle high-angle boundary separated by layer fcc-based long-period structure containing intrinsic stacking faults, (2) the high-energy breaks nanometer-size facets, some which are not $\ensuremath{\Sigma}11$ do even belong to any coincident-site...
A neutron-\ensuremath{\alpha}-particle coincidence experiment was performed to study breakup of $^{6}\mathrm{He}$ on a $^{209}\mathrm{Bi}$ target at an incident energy 22.5 MeV. Direct breakup, as well through the ${2}^{+}$ excited state and also $^{5}\mathrm{He}$$+n$ channel, could be distinguished. total cross section $205\ifmmode\pm\else\textpm\fi{}65$ mb measured. The data compare with coupled-channels calculation that assumes 50% reduction in B(E1) computed from pure...
A new resonance having a relative decay energy of $~0.6$ MeV has been observed above the two-neutron separation in $^{24}\mathrm{O}$ at an excitation $~7.5$ MeV. The level was found to directly feed first excited state $^{23}\mathrm{O}$, $E=0.045(2)$-MeV resonance, through measurement neutron-neutron correlations. Energy comparisons with $^{23}\mathrm{O}$ suggest that this is dominated by unpaired neutron $\ensuremath{\nu}0{d}_{3/2}$ single-particle orbital coupled single hole...
The cross sections for elastic scattering of 318 MeV $^{6}\mathrm{Li}$ from $^{12}\mathrm{C}$ and $^{28}\mathrm{Si}$ were measured. data extend well beyond the rainbow angle into region where far-side dominates, thus define unique phenomenological potentials. These complement earlier potentials derived at an energy 210 MeV. Double-folded real also generated using effective nucleon-nucleon interactions. M3Y Franey-Love 50 interactions gave similar A Woods-Saxon form was used imaginary...
The decay of the neutron unbound ground state 18B was studied for first time through a single-proton knockout reaction from 62 MeV/u 19C beam. energy spectrum reconstructed coincidence measurements between emitted and 17B fragment using MoNA/Sweeper setup. An s-wave line shape used to describe experimental resulting in an upper limit scattering length −50 fm which corresponds <10 keV. Observing provides verification that includes large component. presence this component shows s–d mixing is...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAutomatic Measurement of Light Absorption and Fluorescence on Paper ChromatogramsJ. A. Brown M. MarshCite this: Anal. Chem. 1953, 25, 12, 1865–1869Publication Date (Print):December 1, 1953Publication History Published online1 May 2002Published inissue 1 December 1953https://pubs.acs.org/doi/10.1021/ac60084a020https://doi.org/10.1021/ac60084a020research-articleACS PublicationsRequest reuse permissionsArticle Views33Altmetric-Citations15LEARN ABOUT...