A5034504011- Nuclear physics research studies
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Astronomical and nuclear sciences
- Quantum Chromodynamics and Particle Interactions
- Quantum, superfluid, helium dynamics
- Advanced Chemical Physics Studies
- Rare-earth and actinide compounds
- Nuclear reactor physics and engineering
- X-ray Spectroscopy and Fluorescence Analysis
- Atomic and Subatomic Physics Research
- Nuclear Materials and Properties
- Particle accelerators and beam dynamics
- Particle Detector Development and Performance
- Radiopharmaceutical Chemistry and Applications
- Cold Fusion and Nuclear Reactions
- Particle physics theoretical and experimental studies
- Ion-surface interactions and analysis
- High-pressure geophysics and materials
- Radiation Detection and Scintillator Technologies
- Neutrino Physics Research
- Superconducting Materials and Applications
- Chemical Synthesis and Characterization
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
Instituto Nacional de Investigaciones Nucleares
2015-2025
University of Notre Dame
1986-2020
Joint Institute for Nuclear Astrophysics
2020
Comisión Nacional de Energía Atómica
2001-2018
Australian National University
2016
Universidad de Huelva
2012
Universidad Nacional Autónoma de México
1980-2009
Universidad Autónoma del Estado de México
2003-2006
Hope College
2000
Oak Ridge National Laboratory
1980
The fusion of ${}^{6}\mathrm{He}$ with a ${}^{209}\mathrm{Bi}$ target has been studied at energies near to and below the Coulomb barrier. Despite weak binding valence neutrons in ${}^{6}\mathrm{He}$, little evidence is found for suppression due projectile breakup. Instead, large enhancement sub-barrier observed. It suggested that this may arise from coupling positive $Q$ value neutron transfer channels, resulting ``neutron flow'' between target.
Elastic scattering of $^{8}\mathrm{B}$, $^{7}\mathrm{Be}$, and $^{6}\mathrm{Li}$ on a $^{58}\mathrm{Ni}$ target has been measured at energies near the Coulomb barrier. Optical-model fits were made to experimental angular distributions, total reaction cross sections deduced. A comparison with other systems provides striking evidence for proton-halo effects $^{8}\mathrm{B}$ reactions. As opposed situation neutron-halo nucleus $^{6}\mathrm{He}$, which particle transfer dominates, ``extra''...
The present status of fusion reactions involving light (A < 20) radioactive projectiles at energies around the Coulomb barrier (E 10 MeV per nucleon) is reviewed, emphasizing measurements made within last decade. Data on elastic scattering (providing total reaction cross section information) and breakup channels for involved systems, demonstrating relationship between these channel, are also reviewed. Similarities differences in behavior data concerning halo nuclei, weakly-bound but less...
Reaction products from the interaction of ${}^{6}\mathrm{He}$ with ${}^{209}\mathrm{Bi}$ have been measured at energies near Coulomb barrier. A ${}^{4}\mathrm{He}$ group remarkable intensity, which dominates total reaction cross section, has observed. The angular distribution suggests that it results primarily a direct nuclear process. It is likely this transfer and/or breakup channel doorway state accounts for previously observed large sub-barrier fusion enhancement in system.
The interaction of ${}^{6}\mathrm{He}$ with ${}^{209}\mathrm{Bi}$ has been studied over a range energies well below the nominal Coulomb barrier. A ${}^{4}\mathrm{He}$ group remarkable intensity, first observed in previous experiment at near-barrier energies, continues to dominate reaction sub-barrier regime. total cross section nearly 200 mb was measured for this 6 MeV This very large value is shown be consistent deduced from simultaneously-measured elastic scattering angular distribution.
In this paper we analyze the nuclear fusion rate between equal nuclei for all five different burning regimes in dense matter (two thermonuclear regimes, two pycnonuclear ones, and intermediate regime). The is determined by Coulomb barrier penetration environments astrophysical S-factor at low energies. We evaluate previous studies of problem propose a simple phenomenological formula reaction which covers cases. parameters can be varied, taking into account current theoretical uncertainties...
Fusion excitation functions are measured for the $\ensuremath{\alpha},p$, and $n$ evaporation channels in fusion of $^{12}\mathrm{C}+^{12}\mathrm{C}$ system at center-of-mass energies between 4.42 6.48 MeV, with energy steps 75 keV. The \ensuremath{\gamma}-ray technique is used a new absolute normalization method which independent charge collection, allowing one to monitor same time carbon buildup target. Discrepancies previous works discussed simple unification proposed. Barrier penetration...
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.
Carbon and oxygen burning reactions, in particular, $^{12}$C+$^{12}$C fusion, are important for the understanding interpretation of late phases stellar evolution as well ignition nucleosynthesis cataclysmic binary systems such type Ia supernovae x-ray superbursts. A new measurement this reaction has been performed at University Notre Dame using particle-$\gamma$ coincidence techniques with SAND (a silicon detector array) high-intensity 5U Pelletron accelerator. New results fusion low...
The reaction dynamics for the proton halo nucleus $^{8}\mathrm{B}$ $+$ $^{\mathrm{nat}}\mathrm{Zr}$ is explored through an elastic scattering measurement at sub-Coulomb barrier energy of 26.5 MeV. differential angular distribution has been measured and total cross section as well interaction distance are derived via optical model analysis. present result combined with relevant values in comparison $^{6}\mathrm{He}$, $^{7}\mathrm{Be}$, $^{6,7}\mathrm{Li}$, $^{16}\mathrm{O}$ on various targets...
We use the continuum discretized coupled channel (CDCC) method to investigate effects of breakup coupling on $^{8}\mathrm{B}+^{58}\mathrm{Ni}$ elastic scattering. evaluate angular distributions at several collision energies and show that our theoretical results are in excellent agreement with recent data Aguilera et al. [Phys. Rev. C 79, 021601(R) (2009)]. nuclear excitations target have a weak influence but inclusion continuum-continuum couplings is essential reproduce data.
The cross section for \ensuremath{\alpha}-particle emission in the $^{6}\mathrm{He}+^{209}\mathrm{Bi}$ reaction at energies near Coulomb barrier is remarkably large. Possible reactions that may produce observed \ensuremath{\alpha} particles include two-neutron transfer, one-neutron and direct projectile breakup. Each of these mechanisms results a distinctive angular correlation between particle outgoing neutron(s). A neutron-\ensuremath{\alpha}-particle coincidence experiment was performed...
Angular distributions for the elastic scattering of $^{8}\mathrm{B}$, $^{7}\mathrm{Be}$, and $^{6}\mathrm{Li}$ on a $^{12}\mathrm{C}$ target have been measured at ${E}_{\mathrm{lab}}=25.8$, 18.8, 12.3 MeV, respectively. The analyses these angular performed in terms optical model using Woods-Saxon double-folding type potentials. effect breakup ${}^{8}\mathrm{B}+{}^{12}\mathrm{C}$ is investigated by performing coupled-channels calculations with continuum discretized coupled-channel method...
We report the first evidence of breakup dominance at deep sub-barrier energies for proton halo nucleus $^{8}\mathrm{B}$ on a heavy target. Angular distribution measurements fragment, $^{7}\mathrm{Be}$, lead were performed TwinSol facility University Notre Dame beam energy 30 MeV, 58% Coulomb barrier and corresponding to distance closest approach 20.5 fm. The $^{7}\mathrm{Be}$ yield was observed in two double sided silicon strip detector telescopes symmetrical radioactive normalized using...
We present $^{8}\mathrm{B}+^{27}\mathrm{Al}$ elastic scattering angular distributions for the proton-halo nucleus $^{8}\mathrm{B}$ at two energies above Coulomb barrier, namely ${E}_{\mathrm{lab}}=15.3$ and 21.7 MeV. The experiments were performed in Radioactive Ion Beams Brasil facility (RIBRAS) S\~ao Paulo, TwinSol University of Notre Dame, USA. measured range 15--80 degrees. Optical model continuum discretized coupled channels calculations performed, total reaction cross sections derived....
Fusion excitation functions were obtained for $^{16}\mathrm{O}$ + $^{70,72,73,74,76}\mathrm{Ge}$ at energies from about 4 MeV below to 15 or more above the Coulomb barrier. The barrier parameters extracted data agree within 2% with those systematics fusion Low-energy enhancements are observed whose behavior is explained context of simple model calculations by assigning appropriate degrees freedom respective reaction partners. These consistent used in similar analysis different sets where...
Fusion excitation functions were obtained for $^{27}\mathrm{Al}$${+}^{70,72,73,74,76}$Ge at energies from about 6 MeV below to 7 above the Coulomb barrier. One-dimensional barrier penetration model calculations with one free parameter yield parameters in good agreement systematics fusion Large low-energy enhancements are observed whose trend suggests presence of a structural change between $^{70,72}\mathrm{Ge}$ and $^{73,74,76}\mathrm{Ge}$. Within context simple calculations, this is...
A parametrization of the interaction-barrier model C. Y. Wong [Phys. Rev. Lett. 31, 766 (1973)] is given for light, weakly bound projectiles and also exotic ``halo'' nuclei $^{6}\mathrm{He}$ $^{8}\mathrm{B}$. Comparisons are made with original parametrization. The extremely anomalous behavior interaction radius barrier curvature halo discussed.
Experimental reaction cross sections for $^{6}\mathrm{He}$ and $^{4}\mathrm{He}$ projectiles are reduced shown to follow well-defined trajectories that can be characterized by respective Wong-type curves. The strong enhancement observed the data is interpreted as caused two separate halo effects: a size effect, which affects whole energy region, dynamic important only near below barrier. Evidence core-halo decoupling presented ${}^{6}\mathrm{He}+{}^{64}\mathrm{Zn}$ system, further supports...
Previously reported data for fusion of the $^{8}\mathrm{B}+(^{58}\mathrm{Ni},^{28}\mathrm{Si})$ systems are critically reviewed. New $\ensuremath{\alpha}\text{-particle}$ from $^{8}\mathrm{B}+^{58}\mathrm{Ni}$ also reported, but paper is mostly based on using realistic calculations well-established codes to reanalyze previous data. The influence breakup protons evaporation proton measurements heavier system found be small at all energies except lowest one measured, and corrections made this...
Elastic scattering angular distributions of the radioactive weakly bound $^{7}\mathrm{Be}$ on $^{27}\mathrm{Al}$ have been measured at energies near Coulomb barrier. The interaction optical potential is investigated by using different potentials. Total reaction cross sections also obtained.
The interaction of ${}^{8}\mathrm{Li}$ with ${}^{208}\mathrm{Pb}$ has been studied over a range energies near the nominal Coulomb barrier. An excitation function for total reaction cross section is obtained from elastic-scattering angular distributions and compared existing data ${}^{6,7}\mathrm{Li}$ scattering. result this comparison indicates that barrier ${}^{8}\mathrm{Li}{+}^{208}\mathrm{Pb}$ reduced by approximately 4 MeV relative to ${}^{7}\mathrm{Li}.$ yields ${}^{7}\mathrm{Li}$...
Recent experimental results for the fusion of proton-halo system ${}^{8}\text{B}\phantom{\rule{-0.16em}{0ex}}+\phantom{\rule{-0.16em}{0ex}}{}^{58}\text{Ni}$ are discussed. A strong enhancement is observed both below and above barrier. This qualitatively different from usual sub-barrier many heavy-ion systems. Arguments given that relate to a static halo effect directly associated extended size state. simple single-barrier model proposed which describes cross sections in terms maximum angular...