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7 results on '"S. Burcher"'

3. Cross-section measurements to low-lying excited final states in the Mg24(α,p)Al*27(γ) reaction as an energy source for x-ray bursts

Author

C. Thornsberry, S. Burcher, Karl Smith, Carl R. Brune, S. L. Henderson, K. T. Macon, K. Y. Chae, Richard deBoer, D. W. Bardayan, K. L. Jones, Robert Grzywacz, Maxime Renaud, Shea Mosby, B. Vande Kolk, Patrick O'Malley, Michael Wiescher, Khachatur V. Manukyan, A. Boeltzig, Sebastian Aguilar, Tan Ahn, and Jerome Kovoor

Subjects
Physics, Nuclear reaction, Degree (graph theory), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Type (model theory), 01 natural sciences, Excited state, 0103 physical sciences, Production (computer science), Sensitivity (control systems), Atomic physics, 010306 general physics, Energy source, Energy (signal processing)
Abstract

Energy production in Type Ia x-ray bursts depends on a number of nuclear reactions that become efficient in a hot environment (up to 2 GK). Model sensitivity studies have been performed in an effort to better identify the reactions that have the largest effect, but these efforts are hampered by the high level of complexity of the astrophysical model and large nuclear physics uncertainties. In a recent study, the $^{24}\mathrm{Mg}(\ensuremath{\alpha},p)^{27}\mathrm{Al}$ reaction was found to significantly affect the energy generation in x-ray bursts. This manuscript reports the first study of the $^{24}\mathrm{Mg}(\ensuremath{\alpha},{p}_{1,2}\ensuremath{\gamma})^{27}\mathrm{Al}$ reaction at energies relevant for x-ray bursts. The branches to the $^{27}\mathrm{Al}$ excited states increase to a small degree the estimates of the total astrophysical $^{24}\mathrm{Mg}(\ensuremath{\alpha},p)^{27}\mathrm{Al}$ reaction rate.

Published
2020
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4. γ -ray spectroscopy of astrophysically important states in Ca39

Author

H. Sims, S. Burcher, J. Hu, Eunji Lee, Jacob Allen, G. L. Wilson, C. L. Jiang, Wanpeng Tan, S. M. Cha, M. R. Hall, T.R. Baugher, Paul Thompson, K.L. Jones, M. P. Carpenter, R. L. Varner, A. D. Ayangeakaa, Andrew Ratkiewicz, Kelly Chipps, Patrick O'Malley, Bertis Rasco, Sunghoon Ahn, O. Hall, J. A. Cizewski, S. D. Pain, K. Y. Chae, C. Thornsberry, A. Lepailleur, J. C. Blackmon, David Walter, J. T. Anderson, Karl Smith, Michael Febbraro, D. W. Bardayan, Daniel Santiago-Gonzalez, S. Ota, D. Seweryniak, and S. Zhu

Subjects
Physics, Atomic physics, Spectroscopy
Published
2020
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5. Constraining spectroscopic factors near the r -process path using combined measurements: Kr86 (d, p)87Kr

Author

J. A. Cizewski, Kelly Chipps, S. Burcher, Sunghoon Ahn, Filomena Nunes, Paul Thompson, C. Thornsberry, Thomas Baumann, Brett Manning, G. Cerizza, S. J. Williams, S. J. Lonsdale, S. Ota, D. W. Bardayan, Fernando Montes, Patrick O'Malley, Andrew Ratkiewicz, R. L. Kozub, D. Bazin, S. D. Pain, T.R. Baugher, K.L. Jones, J. Pereira, and David Walter

Subjects
Physics, Path (graph theory), r-process, Computational physics
Published
2019
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6. New γ -ray transitions observed in Ne19 with implications for the O15(α,γ)Ne19 reaction rate

Author

O. Hall, J. A. Cizewski, S. Burcher, H. Sims, Jacob Allen, S. Ota, K.L. Jones, R. L. Varner, Patrick O'Malley, G. L. Wilson, M. R. Hall, Paul Thompson, Kelly Chipps, Bertis Rasco, Sunghoon Ahn, J. Hu, C. Thornsberry, Eunji Lee, M. P. Carpenter, A. Lepailleur, S. Zhu, D. Seweryniak, K. Y. Chae, T.R. Baugher, J. T. Anderson, S. M. Cha, A. D. Ayangeakaa, Andrew Ratkiewicz, Wanpeng Tan, S. D. Pain, C. L. Jiang, Daniel Santiago-Gonzalez, D. W. Bardayan, Karl Smith, Michael Febbraro, J. C. Blackmon, and David Walter

Subjects
Physics, CNO cycle, Spins, 010308 nuclear & particles physics, Gamma ray, Type (model theory), 01 natural sciences, Nuclear physics, Reaction rate, 0103 physical sciences, Nuclear astrophysics, Gammasphere, 010306 general physics, National laboratory
Abstract

The $^{15}$O($\alpha$,$\gamma$)$^{19}$Ne reaction is responsible for breakout from the hot CNO cycle in Type I x-ray bursts. Understanding the properties of resonances between $E_x = 4$ and 5 MeV in $^{19}$Ne is crucial in the calculation of this reaction rate. The spins and parities of these states are well known, with the exception of the 4.14- and 4.20-MeV states, which have adopted spin-parities of 9/2$^-$ and 7/2$^-$, respectively. Gamma-ray transitions from these states were studied using triton-$\gamma$-$\gamma$ coincidences from the $^{19}$F($^{3}$He,$t\gamma$)$^{19}$Ne reaction measured with GODDESS (Gammasphere ORRUBA Dual Detectors for Experimental Structure Studies) at Argonne National Laboratory. The observed transitions from the 4.14- and 4.20-MeV states provide strong evidence that the $J^\pi$ values are actually 7/2$^-$ and 9/2$^-$, respectively. These assignments are consistent with the values in the $^{19}$F mirror nucleus and in contrast to previously accepted assignments.

Published
2019
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7. Transition from collectivity to single-particle degrees of freedom from magnetic moment measurements on 3882Sr 44 and 3890Sr 52

Author

Kamila Sieja, G. J. Kumbartzki, Michael Slater, S. L. Rice, V. I. Zherebchevsky, A. Cudd, Yitzhak Sharon, Jason Burke, Andrew Ratkiewicz, Shadow J. Q. Robinson, M. McCleskey, S. Yu. Torilov, Antti Saastamoinen, S. Burcher, Michael M. Henry, Steven D. Pain, G. Gurdal, Larry Zamick, A. Spiridon, N. Benczer-Koller, K.-H. Speidel, and D. A. Torres

Subjects
Physics, Nuclear and High Energy Physics, Condensed matter physics, Magnetic moment, 010308 nuclear & particles physics, Nuclear Theory, Krypton, Degrees of freedom (physics and chemistry), Nuclear structure, chemistry.chemical_element, Coulomb excitation, 01 natural sciences, Fragility, chemistry, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Particle, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

The evolution of shell structure and the fragility of the benchmark magic numbers is a topic of major interest in nuclear-structure physics. The authors measured the structure-sensitive $g$ factors of states in unstable even-even strontium isotopes, following $\ensuremath{\alpha}$-pickup reactions by krypton beams from a carbon target. The results help elucidate how protons and neutrons contribute to the evolution of nuclear structure in this important mass region where rapid structural changes occur.

Published
2014
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