A5089390770- Nuclear physics research studies
- Nuclear Physics and Applications
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Nuclear reactor physics and engineering
- Atomic and Molecular Physics
- Medical Imaging Techniques and Applications
- Atomic and Subatomic Physics Research
- X-ray Spectroscopy and Fluorescence Analysis
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Gamma-ray bursts and supernovae
- Astronomical and nuclear sciences
- Quantum, superfluid, helium dynamics
- Particle accelerators and beam dynamics
- Advanced NMR Techniques and Applications
- Astro and Planetary Science
- Neutrino Physics Research
- Advanced Chemical Physics Studies
- Superconducting Materials and Applications
- Particle Accelerators and Free-Electron Lasers
- Radiation Therapy and Dosimetry
- Distributed and Parallel Computing Systems
- Astrophysical Phenomena and Observations
- Inorganic Fluorides and Related Compounds
Louisiana State University
2016-2025
Oak Ridge National Laboratory
2004-2023
Florida State University
2017
Lawrence Livermore National Laboratory
2017
Joint Institute for Nuclear Astrophysics
2016
Oak Ridge Associated Universities
2009-2011
University of Tennessee at Knoxville
2009-2011
Rutgers, The State University of New Jersey
2009-2011
Colorado School of Mines
2009-2011
Ohio University
2009
The rate of the (17)F(p,gamma)(18)Ne reaction is important in various astrophysical events. A previous (17)F(p,p)(17)F measurement identified a 3;{+} state providing strongest resonance contribution, but strength was unknown. We have directly measured using mixed beam (17)F and (17)O at ORNL. for (18)Ne found to be omegagamma = 33 +/- 14(stat) +/-1 7(syst) meV, corresponding gamma width Gamma_{gamma} 56 24(stat) 30(syst) meV. An upper limit on direct capture S(E) <or= 65 keV b determined an...
The best examples of halo nuclei, exotic systems with a diffuse nuclear cloud surrounding tightly bound core, are found in the light, neutron-rich region, where neutrons experience only weak binding and weak, or no, potential barrier. Modern direct-reaction measurement techniques provide powerful probes structure nuclei. Despite more than four decades these studies on benchmark one-neutron nucleus 11Be, spectroscopic factors for two states remain poorly constrained. In present work,...
Knowledge of the astrophysical rate ${}^{18}\mathrm{F}(p,\ensuremath{\alpha}{)}^{15}\mathrm{O}\mathrm{}$ reaction is important for understanding \ensuremath{\gamma}-ray emission expected from novae and heavy-element production in x-ray bursts. The this dominated at temperatures above $\ensuremath{\sim}0.4$ GK by a resonance near 7.08 MeV excitation energy ${}^{19}\mathrm{Ne}.$ ${}^{18}\mathrm{F}(p,\ensuremath{\alpha}{)}^{15}\mathrm{O}$ has been uncertain part because disagreements among...
The ${}^{17}\mathrm{F}(p,\ensuremath{\gamma}{)}^{18}\mathrm{Ne}$ reaction is important in stellar explosions, but its rate has been uncertain because of an expected ${3}^{+}$ state ${}^{18}\mathrm{Ne}$ that never conclusively observed. This would provide a strong $\ensuremath{\ell}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0$ resonance and, depending on excitation energy, could dominate the rate. We have observed this missing by measuring...
The (d,p) neutron transfer and (d,d) elastic scattering reactions were measured in inverse kinematics using a radioactive ion beam of 132Sn at 630 MeV. data taken region where Rutherford dominated the reaction, nuclear effects account for less than 8% cross section. magnitude was found to be independent optical potential used, allowing normalized reliable manner. neutron-transfer reaction populated previously unmeasured state 1363 keV, which is most likely single-particle 3p1/2 expected...
Recent calculations suggest that the rate of neutron capture by $^{130}\mathrm{Sn}$ has a significant impact on late-time nucleosynthesis in $r$ process. Direct into low-lying bound states is expected to be near $N=82$ closed shell, so $r$-process reaction rates may strongly impacted properties single particle this region. In order investigate these properties, ($d$,$p$) been studied inverse kinematics using 630 MeV beam ($4.8\text{ }\text{ }\mathrm{MeV}/\mathrm{u}$) and...
We report total absorption spectroscopy measurements of ^{92}Rb, ^{96gs}Y, and ^{142}Cs β decays, which are the most important contributors to high energy ν[over ¯]_{e} spectral shape in nuclear reactors. These three decays contribute 43% flux near 5.5 MeV emitted by This is particularly interesting due features recently observed several experiments including Daya Bay, Double Chooz, RENO Collaborations. Measurements were conducted at Oak Ridge National Laboratory means proton-induced fission...
The synthesis of heavy elements in supernovae is affected by low-energy <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mo>(</a:mo><a:mi>n</a:mi><a:mo>,</a:mo><a:mi>p</a:mi><a:mo>)</a:mo></a:mrow></a:math> and <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mrow><b:mo>(</b:mo><b:mi>p</b:mi><b:mo>,</b:mo><b:mi>n</b:mi><b:mo>)</b:mo></b:mrow></b:math> reactions on unstable nuclei, yet experimental data such reaction rates are scarce. SECAR (SEparator for CApture...
Production of the radioisotope 18F in novae is severely constrained by rate 18F(p,alpha)15O reaction. A resonance at E(c.m.)=330 keV may strongly enhance reaction rate, but its strength has been very uncertain. We have determined this important measuring cross section on and off using a radioactive beam ORNL Holifield Radioactive Ion Beam Facility. find that 1.48+/-0.46 eV, it dominates over significant range temperatures characteristic ONeMg novae.
Angular distributions of the analyzing powers ${\mathrm{iT}}_{11},$ ${T}_{20},$ and ${T}_{22}$ for ${}^{1}\mathrm{H}(d\ensuremath{\rightarrow},\ensuremath{\gamma}{)}^{3}\mathrm{He}$ at $40<~{E}_{\mathrm{c}.\mathrm{m}.}<~110$ keV angular distribution power ${A}_{y}$ ${}^{2}\mathrm{H}(p\ensuremath{\rightarrow},\ensuremath{\gamma}{)}^{3}\mathrm{He}$ $70<~{E}_{\mathrm{c}.\mathrm{m}.}<~210$ have been measured first time. In addition, absolute differential cross sections proton-deuteron capture...
States near the ${}^{22}\mathrm{Ne}+p$ threshold in ${}^{23}\mathrm{Na}$ were investigated using ${}^{22}\mathrm{Ne}{(}^{3}\mathrm{He}{,d)}^{23}\mathrm{Na}$ reaction over angular range of $5\ifmmode^\circ\else\textdegree\fi{}<~{\ensuremath{\theta}}_{\mathrm{lab}}<~35\ifmmode^\circ\else\textdegree\fi{}$ at ${E(}^{3}\mathrm{He})=20 \mathrm{MeV}.$ Spectroscopic factors extracted for states corresponding to resonances ${}^{22}\mathrm{Ne}(p,\ensuremath{\gamma}{)}^{23}\mathrm{Na}$ reaction. Two...
We used the $^{16}\mathrm{O}$${(}^{3}$He,n${)}^{18}$Ne, $^{12}\mathrm{C}$${(}^{12}$C${,}^{6}$He${)}^{18}$Ne, and $^{20}\mathrm{Ne}$(p,t${)}^{18}$Ne reactions to study $^{18}\mathrm{Ne}$ states up an excitation energy of 10 MeV, with emphasis on levels corresponding $^{14}\mathrm{O}$(\ensuremath{\alpha},p${)}^{17}$F $^{17}\mathrm{F}$(p,\ensuremath{\gamma}${)}^{18}$Ne resonances that could strongly affect these reaction rates in hot stellar environments. Excitation energies, widths, absolute...
States near the $^{23}\mathrm{Na}+p$ threshold in $^{24}\mathrm{Mg}$ were investigated using $^{23}\mathrm{Na}(^{3}\mathrm{He},d)^{24}\mathrm{Mg}$ reaction over angular range of $5\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\leqslant}{\ensuremath{\theta}}_{\mathrm{lab}}\ensuremath{\leqslant}35\ifmmode^\circ\else\textdegree\fi{}$ at $E(^{3}\mathrm{He})=20\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$. Spectroscopic factors extracted for states corresponding to resonances...
The extraction of detailed nuclear structure information from transfer reactions requires reliable, well-normalized data as well optical potentials and a theoretical framework demonstrated to work in the relevant mass beam energy ranges. It is rare that ingredients can be tested for exotic nuclei owing paucity data. halo nucleus Be-11 has been examined through 10Be(d,p) reaction inverse kinematics at equivalent deuteron energies 12,15,18, 21.4 MeV. Elastic scattering Be-10 on protons was...
The cross section for the astrophysically important $^{17}O(p,\ensuremath{\alpha})^{14}N$ reaction was measured at proton energies of 75 and 65 keV. Thick, high-purity ${\mathrm{Ta}}_{2}{O}_{5}$ targets (77% enriched $^{17}O$) large-area detectors were used with beam currents 0.45 mA. Backgrounds using natural isotopic composition. expected resonance ${E}_{p}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}70$ keV observed in data taken keV, its width found to be...
Knowledge of the ${}^{17}\mathrm{F}(p,\ensuremath{\gamma}{)}^{18}\mathrm{Ne}$ reaction rate is important for understanding stellar explosions, but it was uncertain because properties an expected previously unobserved ${3}^{+}$ state in ${}^{18}\mathrm{Ne}$ were not known. This would provide a strong s-wave resonance ${}^{17}\mathrm{F}+p$ system and, depending on its excitation energy, could dominate at temperatures above 0.2 GK. We have observed this missing by measuring...
The $^{2}\mathrm{H}$($^{82}\mathrm{Ge}$,$p$)$^{83}\mathrm{Ge}$ and $^{2}\mathrm{H}$($^{84}\mathrm{Se}$,$p$)$^{85}\mathrm{Se}$ reactions were studied with radioactive beams of $^{82}\mathrm{Ge}$ $^{84}\mathrm{Se}$ at beam energies ${E}_{\mathrm{beam}}=330$ 380 MeV, respectively. Excitation energies, proton angular distributions, asymptotic normalization coefficients have been determined for the lowest lying states $^{83}\mathrm{Ge}$ $^{85}\mathrm{Se}$. Spectroscopic factors also extracted...
Knowledge of the $^{18}\mathrm{F}$($p,\ensuremath{\alpha}$)$^{15}\mathrm{O}$ and $^{18}\mathrm{F}$($p,\ensuremath{\gamma}$)$^{19}\mathrm{Ne}$ astrophysical reaction rates are important to understand \ensuremath{\gamma}-ray emission from nova explosions heavy-element production in x-ray bursts. The for these reactions have been uncertain, part due a lack comprehensive examination available structure information compound nucleus $^{19}\mathrm{Ne}$. We examined latest experimental measurements...
The combination of γ-ray spectroscopy and charged-particle is a powerful tool for the study nuclear reactions with beams nuclei far from stability. This paper presents new silicon detector array, SHARC, Silicon Highly-segmented Array Reactions Coulex. array used at radioactive-ion-beam facility TRIUMF (Canada), in conjunction TIGRESS spectrometer, built custom Si-strip detectors utilising fully digital readout. SHARC has more than 50% efficiency, approximately 1000-strip segmentation,...
The Galactic 1.809-MeV γ-ray signature from the β decay of ^{26g}Al is a dominant target astronomy, which significant component understood to originate massive stars. ^{26g}Al(p,γ)^{27}Si reaction major destruction pathway for at stellar temperatures, but rate poorly constrained due uncertainties in strengths low-lying resonances ^{27}Si. ^{26g}Al(d,p)^{27}Al has been employed inverse kinematics determine spectroscopic factors, and hence resonance strengths, proton ^{27}Si via mirror...