Bulletin of the American Physical Society
2011 Fall Meeting of the APS Division of Nuclear Physics
Volume 56, Number 12
Wednesday–Saturday, October 26–29, 2011; East Lansing, Michigan
Session JF: Nuclear Structure VI |
Hide Abstracts |
Chair: Grigory Rogachev, Florida State University Room: 104AB |
Friday, October 28, 2011 2:00PM - 2:12PM |
JF.00001: Spectroscopy of neutron-unbound $^{15}$Be Jesse Snyder, Michael Thoennessen, Thomas Baumann, Artemis Spryou, Michael Strongman, Greg Christian, Shea Mosby, Michelle Mosby, Jenna Smith, Anna Simon, Bryan Luther, Sharon Stephenson, Alex Peters, Paul DeYoung, Eric Lunderberg, Joseph Finck A (d,p) reaction was used to populate neutron unbound states in $^{15}$Be from a secondary beam of $^{14}$Be at 55MeV/u. These unbound states in $^{15}$Be decayed though the emission of a neutron and a $^{14}$Be fragment. The neutron was detected using MoNA, an array of 144 plastic scintillator bars. The charged $^{14}$Be fragments were deflected by the Sweeper dipole magnet into a system of charged particle detectors which allow the reconstruction of their kinematic properties. The decay energy was calculated through invariant mass analysis, using the energy and momentum information of the neutron and fragment at the target. Preliminary results will be presented. [Preview Abstract] |
Friday, October 28, 2011 2:12PM - 2:24PM |
JF.00002: Spectroscopy of Neutron Unbound Carbon Isotopes S. Mosby, M. Thoennessen, P. DeYoung Neutron unbound states in neutron-rich carbon isotopes were populated via knockout reactions from a $^{22}$N beam at the National Superconducting Cyclotron Laboratory at Michigan State University. The Modular Neutron Array (MoNA) was used to measure the energy and position of emitted neutrons near zero degrees, while the remaining charged fragments were detected in a series of position and energy-sensitive detectors behind the MSU/FSU Sweeper magnet. The decay energy was then reconstructed event-by-event from the four-momentum vectors of the neutron and fragment. Results from the current analysis, including decay energy spectra for $^{19,20,21}$C and interpretation, will be presented. [Preview Abstract] |
Friday, October 28, 2011 2:24PM - 2:36PM |
JF.00003: Spectroscopy of $^{13}$Li E.M. Lunderberg, C.C. Hall, P.A. DeYoung, M. Thoennessen, J. Snyder The spectroscopy of neutron-unbound levels in $^{13}$Li is presented. The $^{13}$Li were formed by a one-proton knockout reaction from a 53.6 MeV/u $^{14}$Be beam at the National Superconducting Cyclotron Laboratory. The decay energy spectrum was measured with the Modular Neutron Array (MoNA) and Sweeper superconducting dipole magnet experimental setup. $^{13}$Li decays via two-neutron emission and Geant4 simulations will be shown. The results will also be compared to Yu. Aksyutina \textit{et al.}, Phys. Lett B \textbf{666}, 430 (2008). [Preview Abstract] |
Friday, October 28, 2011 2:36PM - 2:48PM |
JF.00004: The search for nuclear molecules in isobaric analog states of $^{10}$B Anthony Kuchera, Grigory Rogachev, Vladilen Goldberg, Eric Johnson, Laniece Miller, Silvio Cherubini, Marisa Gulino, John Hardy, Marco La Cognata, Marcello Lattuada, Rosario Gianluca Pizzone, Stefano Romano, Claudio Spitaleri, Robert Tribble, Wladek Trzaska, Aurora Tumino The highly deformed rotational band in $^{10}$Be with molecular like $\alpha$:2n:$\alpha$ structure was suggested by [1]. In the work presented here, a search for similar structures in T=1 isobaric analog states in $^{10}$B was performed. The excitation energy range of 8.5 -12.1 MeV was probed using the $^9$Be(p,$\alpha$)$^6$Li(T=1, 3.56 MeV, $0^+$) reaction. An R-matrix analysis was performed which allowed spin-parities and partial widths of the observed states to be determined. The cluster properties of the observed states are discussed. \\[4pt] [1] M. Freer et al, Phys. Rev. Lett. 96, 042501 (2006). [Preview Abstract] |
Friday, October 28, 2011 2:48PM - 3:00PM |
JF.00005: Study of the low-lying structure of the N=49 nucleus, $^{81}$Ge S.H. Ahn, K.L. Jones, S.T. Pittman, D.W. Bardayan, K.Y. Chae, C.D. Nesaraja, S.D. Pain, M.S. Smith, A.S. Adekola, J.A. Cizewski, S. Hardy, M.E. Howard, P.D. O'Malley, W.A. Peters, I. Spassova, K.A. Chipps, J.C. Blackmon, M. Matos, B.C. Rasco The properties of low-lying levels of nuclei near N=50 are important for understanding the evolution of nuclear shell structure further from stability and the rapid neutron capture process, which may occur in supernovae. The low-lying levels of the N=49 nucleus $^{81}$Ge have been studied by measuring the $^{80}$Ge(d,p)$^{81}$Ge reaction at 310 MeV (3.875 MeV/u) in inverse kinematics at the Holifield Radioactive Ion Beam Facility in Oak Ridge National Laboratory. The primary goal of this work is to determine the spins of $^{81}$Ge levels using the angular distribution of observed protons. Details of the experimental setup and a status report on the data analysis will be discussed. [Preview Abstract] |
Friday, October 28, 2011 3:00PM - 3:12PM |
JF.00006: Nuclear Structure Studies of $^{76}$Se and $^{76}$Ge with the $(n, n'\gamma)$ Reaction B.P. Crider, A. Chakraborty, A. Kumar, E.E. Peters, F.M. Prados-Est\'{e}vez, M.T. McEllistrem, S.W. Yates A prominent nucleus which may undergo neutrinoless double beta decay is $^{76}$Ge, which decays to $^{76}$Se. While an unambiguous observation of this lepton-number-violating decay mode has not been made, much work is in progress to obtain the data required for an accurate calculation of the nuclear matrix element (NME), which is vital to extracting the absolute mass scale of the neutrino. In order to provide more information for calculation of the NME, excitation function and gamma-ray angular distributions were performed at the University of Kentucky utilizing the $^{76}$Ge$(n, n'\gamma)$ and $^{76}$Se$(n, n'\gamma)$ reactions. Spectroscopic information such as lifetimes, parities, and new transitions will be presented. [Preview Abstract] |
Friday, October 28, 2011 3:12PM - 3:24PM |
JF.00007: Full distribution of dipole states below 9MeV in $^{76}$Se N. Cooper, V. Werner, M.K. Smith, P.M. Goddard, F. Reichel, J. Beller, M. Fritzsche, N. Pietralla, C. Romig, D. Savran, M. Scheck, K. Sonnabend, J. Wagner, A. Chakraborty, B.P. Crider, E. Peters, S.W. Yates, J. Kelly, R. Raut, G. Rusev, A.P. Tonchev, W. Tornow, D. Deleanu, D. Filipescu, T. Glodariu Systematics of photoexcitation strength near the particle emission threshold has been of great interest in recent years due its importance in stellar nucleosynthesis of certain heavy nuclei. Theories such as the QRPA and its variants are currently used to calculate photoexcitation strength in this energy region, as well as the nuclear matrix element of the hypothetical $0\nu 2\beta$-decay modes, such as $^{76} $Ge$\rightarrow ^{76}$Se$+2e^-$. Dipole states between 2 and 4MeV in $^{76}$Se have been studied using linearly polarized, nearly monoenergetic photons produced by Compton-backscattering at the HI$\vec{\gamma}$S facility. The experiment completes a series of photon scattering experiments performed on this nucleus in the energy region below 9MeV, both at the S-DALINAC and at HI$\vec{\gamma}$S. Collective dipole excitations are investigated. [Preview Abstract] |
Friday, October 28, 2011 3:24PM - 3:36PM |
JF.00008: Intermediate States in the Photoexcitation of $^{176m}$Lu J.J. Carroll, T. Henry, T. Balint, H.-H. Pitz, F. Stedile, U. Kneissl The photoexcitation of $^{176m}$Lu has been studied experimentally using the high-intensity DYNAMITRON accelerator at the University of Stuttgart. Enriched samples of $^{176}$Lu (72.5\%) were irradiated with bremsstrahlung having endpoint energies between 700 -- 2,200 keV. Several intermediate states were identified by which the 3.64 hour isomer was populated, and their energy-integrated cross sections were measured. The results and implications for stellar nucleosynthesis of this odd-odd nuclide will be discussed. [Preview Abstract] |
Friday, October 28, 2011 3:36PM - 3:48PM |
JF.00009: Testing the Mutually Enhanced Magicity (MEM) effect in the Giant Monopole Resonance (GMR) in the $^{204-208}$Pb isotopes D. Patel, U. Garg, G.P.A. Berg, T. Adachi, H. Akimune, Y. Fujita, M. Fujiwara, M. Harakeh, M. Itoh, C. Iwamoto, A. Long, J. Matta, T. Murakami, A. Okamoto, K. Sault, R. Talwar, M. Uchida, M. Yosoi Recent study of the giant monopole resonance (GMR) in the even A, $^{112-124}$Sn[1] and $^{106-116}$Cd isotopes showed discrepancy in the centroid energy of GMR peak when compared with the theoretical calculations. It has been suggested [2] that this discrepancy might result from the MEM effect [3]. A consequence of this hypothesis would be significantly high GMR energy in the doubly-magic $^{208}$Pb nucleus when compared with the nearby Pb isotopes. We have investigated GMR in $^{204-208}$Pb isotopes in an experiment performed at RCNP, Osaka University, Japan. Measurements were taken at forward angles, including 0\r{ }, using a 400 MeV $\alpha $ beam. Preliminary results indicate that this hypothesis does not hold. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700