Study of nuclear reactions with carnon-11 and oxygen-15 radioactive ion beams

2007 2007

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Abstract (summary)

Nuclear reaction study with radioactive ion beams is one of the most exciting research topics in modern nuclear physics. The development of radioactive ion beams has allowed nuclear scientists and engineers to explore many unknown exotic nuclei far from the valley of nuclear stability, and to further our understanding of the evolution of the universe.

The recently developed radioactive ion beam facility at the Lawrence Berkeley National Laboratory's 88-inch cyclotron is denoted as BEARS and provides 11C, 14O and 15O radioactive ion beams of high quality. These moderate to high intensity, proton-rich radioactive ion beams have been used to explore the properties of unstable nuclei such as 12N and 15F.

In this work, the proton capture reaction on 11C has been evaluated via the indirect d(11C,12N)n transfer reaction using the inverse kinematics method coupled with the Asymptotic Normalization Coefficient (ANC) theoretical approach. The total effective 12N11C +p ANC is found to be [special characters omitted] = 1.83 ± 0.27 fm-1. With the high 11C beam intensity available, our experiment showed excellent agreement with theoretical predictions and previous experimental studies. This study also indirectly confirmed that the 11C(p,γ) reaction is a key step in producing CNO nuclei in supermassive low-metallicity stars, bypassing the slow triple alpha process.

The newly developed 15O radioactive ion beam at BEARS was used to study the poorly known level widths of 16F via the p(15O,15O)p reaction. Among the nuclei in the A=16, T=1 isobaric triad, many states in 16N and 16O have been well established, but less has been reported on 16F. Four states of 16F below 1 MeV have been identified experimentally: 0-, 1-, 2-, and 3- (Ex = 0.0, 0.19, 0.42, and 0.72 MeV, respectively). Our study utilized R-matrix analysis and found that the 0- state has a level width of 23.1 ± 2.2 keV, and that the broader 1 - state has a width of 91.1 ± 9.9 keV. The level width of the 2- state is found to be 3.3 ± 0.6 keV which is much narrower than the compiled value of 40 ± 30 keV, while a width of 14.1 ± 1.7 keV for the 3- state is in good agreement with the reported value (< 15 keV). These experimental level widths of all four levels are also in accordance with theoretical predictions using single particle shell model calculation.

Indexing (details)

Nuclear physics
0552: Nuclear physics
0610: Nuclear physics
Identifier / keyword
Applied sciences; Pure sciences; Exotic nuclei; Nuclear reactions; Radioactive ion beams
Study of nuclear reactions with carnon-11 and oxygen-15 radioactive ion beams
Lee, Dongwon
Number of pages
Publication year
Degree date
School code
DAI-B 68/08, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
Cerny, Joseph; Vujic, Jasmina
University of California, Berkeley
University location
United States -- California
Source type
Dissertations & Theses
Document type
Dissertation/thesis number
ProQuest document ID
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
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