Speaker
Alan Wuosmaa
(Western Michigan University)
Description
In light nuclei, the separation between the p and sd shells decreases with increasing N/Z near N=8, and the energy of the 1s1/2 orbital drops below that of the 0d5/2 level. This behavior is largely responsible for the halo-like nature of neutron-rich N=9 nuclei, which contain a loosely-bound 1s1/2 neutron. We have used HELIOS to study neutron transfer with the (d,p) reaction using beams of the unstable nuclei 12B, 13B, and 15C, leading to 13B, 14B, and 16C, corresponding to neutron numbers of N=8, 9, and 10. Of particular interest are the properties of states with one or two neutrons in the 1s0d shell. The exotic beams were produced using the in-flight method. Protons were detected at backward laboratory angles using HELIOS, in coincidence with and forward-recoiling beam-like recoils identified in an array of silicon-detector telescopes. HELIOS is designed specifically to study such reactions in inverse kinematics, and to optimize the excitation-energy resolution in the center-of-mass system. Excitation-energy spectra and angular distributions for these reactions will be presented, as well as relative spectroscopic factors. The data will be compared to the predictions of shell-model calculations for this region. This work was supported by the U.S. Department of Energy, Office of Nuclear Physics under contracts DE-FG02-04ER41320 and DE-AC02-06CH11357, and NSF Grant Nos. PHY-02-16783 and PHY-10-68217.
Primary author
Alan Wuosmaa
(Western Michigan University)
Co-authors
Dr
Augusto Macchiavelli
(Lawrence Berkeley National Laboratory)
Prof.
B. Alex Brown
(Michigan State University)
Dr
Ben Kay
(University of York)
Dr
Birger Back
(Argonne National Laboratory)
Dr
Calem Hoffman
(Argonne National Laboratory)
Dr
Catherine Diebel
(Argonne National Laboratory)
Dr
Dinesh Shetty
(Western Michigan University)
Dr
Hye Young Lee
(Los Alamos National Laboratory)
Dr
Jason Clark
(Argonne National Laboratory)
Dr
John Schiffer
(Argonne National Laboratory)
Dr
Jonathon Lighthall
(Western Michigan University)
Dr
K. Ernst Rehm
(Argonne National Laboratory)
Dr
Martin Alcorta
(Argonne National Laboratory)
Dr
Mathis Wiedeking
(Lawrence Livermore National Laboratory)
Dr
Paul Fallon
(Lawrence Berkeley National Laboratory)
Dr
Peter Bertone
(Argonne National Laboratory)
Dr
Sam Baker
(Argonne National Laboratory)
Mr
Scott Marley
(Western Michigan University)
Prof.
Sean Freeman
(University of Manchester)
Mr
Shadi Bedoor
(Western Michigan University)
