A5012382853- Nuclear physics research studies
- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Superconducting Materials and Applications
- Magnetic confinement fusion research
- Atomic and Molecular Physics
- X-ray Spectroscopy and Fluorescence Analysis
- Fusion materials and technologies
- Particle Accelerators and Free-Electron Lasers
- High-Energy Particle Collisions Research
- Quantum, superfluid, helium dynamics
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Electron and X-Ray Spectroscopy Techniques
- Advanced Chemical Physics Studies
- Advanced X-ray Imaging Techniques
- Radiation Therapy and Dosimetry
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Particle accelerators and beam dynamics
- Advanced NMR Techniques and Applications
- Photocathodes and Microchannel Plates
- Cold Fusion and Nuclear Reactions
University of Virginia
1992-2024
Thomas Jefferson National Accelerator Facility
2012-2024
University of California, Irvine
2024
Heinrich Heine University Düsseldorf
2024
Oak Ridge Associated Universities
2024
Forschungszentrum Jülich
2024
Oak Ridge National Laboratory
2024
Fusion Academy
2014
Fusion (United States)
2014
Fermi National Accelerator Laboratory
2013
New high-precision measurements of $p(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}},\ensuremath{\pi})$ and $p(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}},\ensuremath{\gamma})$ cross sections beam asymmetries have been combined with other polarization ratios in a simultaneous analysis both reactions. Compton scattering has provided two important new constraints on the photopion amplitude. The $E2/M1$ mixing ratio for $N\ensuremath{\rightarrow}\ensuremath{\Delta}$...
Collisions of light photons with relativistic electrons have previously been used to produce polarized γ-ray beams modest (~10%) resolution, but relatively low intensity. In contrast, the LEGS project (Laser+Electron Gamma Source) at Brookhaven will a very high flux (>2×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> s xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ) background-free γ rays whose energy be determined accuracy (ΔE...
Abstract If the nuclei remain polarized, spin polarized fuel can increase fusion power produced in a reactor while using less fuel. This study assesses whether reactions between an unpolarized deuterium (D) beam and principle experimentally ascertain persistence of nuclear polarization magnetic experiment. The differential cross section for D-D depends upon polarization, so state be inferred from measurements products. An evaluation is performed 3-MeV proton detection DIII-D tokamak 81 keV...
The ($p, \ensuremath{\gamma}$) reaction populating highly excited states in $^{28}\mathrm{Si}$ is shown to be dominated by giant dipole resonances built upon one-particle, one-hole states. Each resonance centered at ${E}_{\ensuremath{\gamma}}\ensuremath{\approx}20$ MeV, with a width which increases the energy of state, and strength that simply related proton stripping same final state.
The yield curves of high-energy capture $\ensuremath{\gamma}$ rays from $^{12}\mathrm{C}(^{12}\mathrm{C}, {\ensuremath{\gamma}}_{0})$ and {\ensuremath{\gamma}}_{1})$ were measured at ${\ensuremath{\theta}}_{\mathrm{lab}}=45\ifmmode^\circ\else\textdegree\fi{}$ ${E}_{\mathrm{c}.\mathrm{m}.}=5.0 \mathrm{to} 11.0$ MeV. A ${J}^{\ensuremath{\pi}}={2}^{+}$ resonance, with a width (full half-maximum) 261\ifmmode\pm\else\textpm\fi{}74 keV peak cross section 45\ifmmode^\circ\else\textdegree\fi{}...
We report the electron-induced fission of $^{24}\mathrm{Mg}$ into two ground-state $^{12}\mathrm{C}$ nuclei following monopole excitation at energies between 20 and 22 MeV. The observed cross section exhausts least (8\ifmmode\pm\else\textpm\fi{}2)% linear energy-weighted sum rule $S(E0)$ may form a part giant resonance. In addition, we have peak in ${\ensuremath{\theta}}_{^{12}\mathrm{C}}=45\ifmmode^\circ\else\textdegree\fi{}$ function 22.0 23.5 MeV with width (full half-maximum) 1 angular...
Coincidence measurements of electrodisintegration products have been used to simultaneously study the $^{12}\mathrm{C}$+$^{12}\mathrm{C}$, $^{16}\mathrm{O}$+$^{8}\mathrm{Be}$, and $^{20}\mathrm{Ne}$+$\ensuremath{\alpha}$ decay channels $^{24}\mathrm{Mg}$. Asymmetric fission into is concentrated between 18 28 MeV in $^{24}\mathrm{Mg}$ exhibits resonances with cross sections ten times those symmetric fission. There little correlation among three channels. The yields are not consistent...
Results from three independent measurements of the p(\ensuremath{\gamma}\ensuremath{\rightarrow},${\mathrm{\ensuremath{\pi}}}^{0}$) reaction are presented for incident photon energies between 243 and 314 MeV, c.m. angles 105\ifmmode^\circ\else\textdegree\fi{}, 122\ifmmode^\circ\else\textdegree\fi{}, 150\ifmmode^\circ\else\textdegree\fi{}. The ratio cross sections measured with orthogonal states linear polarization is sensitive to E2 excitation \ensuremath{\Delta} resonace. Comparisons made...
A proton spin-polarizability characterizing backward Compton scattering has been extracted from a dispersion analysis of data between 33 and 309 MeV. This spin-polarizability, "delta" = 27.1 +/-2.2(stat+sys) +2.8/-2.4(model) in units 10^-4 fm^4, differs significantly theoretical estimates which are dominated by pi0 t-channel exchange, indicates new contribution the non-perturbative spin-structure proton. value for removes an apparent inconsistency difference charge polarizabilities above...
New precision measurements of cross sections and polarization asymmetries in the $p(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}},\ensuremath{\gamma}p)$ reaction at 90\ifmmode^\circ\else\textdegree\fi{} c.m. are presented for incident energies between 213 333 MeV. A long-standing problem with earlier experiments that appeared to violate unitarity peak \ensuremath{\Delta} is resolved. Data compared theories based on baryon resonance structure dispersion relations. Recent...
Measurements of $^{16}\mathrm{O}$+ $^{12}\mathrm{C}$ capture in which high-energy $\ensuremath{\gamma}$ rays were detected coincidence with recoiling $^{28}\mathrm{Si}$ nuclei are reported. The $\ensuremath{\gamma}$-ray spectra dominated by strong transitions to the excited $K=0$ prolate band $^{28}\mathrm{Si}$. excitation functions for decays states at 6.7 MeV (${0}^{+}$) and 7.4 (${2}^{+}$) consistent giant dipole resonances. width these resonances is narrower than that oblate ground...
Abstract The use of spin-polarized fusion fuels would provide a significant boost towards the ignition burning plasma. cross section for D + T → α n, be increased by 1.5 if were injected with parallel polarization. Furthermore, our simulations demonstrate additional non-linear power gains in large-scale machines such as ITER, due to alpha heating. Such benefits require survival spin polarizations periods comparable particle confinement time. During 1980s, calculations predicted that could...
A peak in the yield from electron-induced fission of $^{28}\mathrm{Si}$ has been observed at an excitation energy 28.3 MeV, decaying by channel $^{16}\mathrm{O}$(g.s.) + $^{12}\mathrm{C}^{2+}$ (4.43 MeV). The angular distribution carbon nuclei this feature follows ($1\ensuremath{-}{{cos}^{4}\ensuremath{\theta}}_{\mathrm{c}.\mathrm{ }\mathrm{m}.}$) indicating assignment $J=2$ with a projection along axis $K=2\ensuremath{\hbar}$. could be due to excitations giant quadrupole resonance prolate...
New precision angular distribution data for the D(\ensuremath{\gamma},p)n reaction are presented incident photon energies of 191 and 222 MeV. The difference cross sections measured with orthogonal states linear polarization is sensitive to short-range behavior tensor interaction in models nuclear force. Comparisons Bonn Paris potentials illustrate sensitivity.
Polarized solid HD targets in a frozen-spin mode, with superior nuclear physics characteristics and simple operational configurations, have previously been restricted their deployment due to disproportionate target production time respect utilization time. Recent investigations yielded polarization lifetimes, at convenient temperature of 1.5 K, nearly year for both H D high holding fields, more than week sub-Tesla fields. These results, taken together the advent new interesting spin-physics...
New precision measurements of the $^{2}\mathrm{H}$(\ensuremath{\gamma}\ensuremath{\rightarrow},p)n reaction taken with tagged polarized photons, and covering a wide angular range, are presented for incident energies between 113 315 MeV. In region \ensuremath{\Delta} resonance, photodisintegration observables can potentially be used to probe N\ensuremath{\Delta} interaction. Coupled-channel calculations in agreement cross sections measured linear polarization parallel plane but fail account...
A compact time projection chamber (TPC) has been constructed for the LEGS (Laser Electron Gamma Source) experiment at BNL. The TPC uses double GEMs as amplification stage. Position encoding is achieved through charge division using zigzag shaped anode pads. a 35 cm diameter active area and 50 long drift depth. It more than 7000 channels of readout electronics in form custom designed ASICs. novel peak sensing circuit used to measure simultaneously amplitude timing signal from an pad. Test...
High-energy $\ensuremath{\gamma}$ rays from the reaction $^{12}\mathrm{C}$($\ensuremath{\alpha}$,$\ensuremath{\gamma}$) have been observed decaying states between 32 and 39 MeV in $^{16}\mathrm{O}$. A narrow unexpectedly strong line, corresponding to decay a state at 14.8\ifmmode\pm\else\textpm\fi{}0.1 $^{16}\mathrm{O}$, was with an angular distribution suggesting $E2$ component. Structure excitation function of this transition favors resonant rather than direct-capture mechanism....