Study of nuclear reactions with 11C and 15O radioactive ion beams
by Lee, Dongwon, Ph.D., UNIVERSITY OF CALIFORNIA, BERKELEY, 2007, 97 pages; 3275482

Abstract:

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.

 
AdvisersJoseph Cerny; Jasmina Vujic
SchoolUNIVERSITY OF CALIFORNIA, BERKELEY
SourceDAI/B 68-08, p. , Nov 2007
Source TypeDissertation
SubjectsNuclear engineering; Nuclear Physics
Publication Number3275482
Adobe PDF Access the complete dissertation:
 

» Find an electronic copy at your library.
  Use the link below to access a full citation record of this graduate work:
  http://gateway.proquest.com/openurl%3furl_ver=Z39.88-2004%26res_dat=xri:pqdiss%26rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation%26rft_dat=xri:pqdiss:3275482
  If your library subscribes to the ProQuest Dissertations & Theses (PQDT) database, you may be entitled to a free electronic version of this graduate work. If not, you will have the option to purchase one, and access a 24 page preview for free (if available).

About ProQuest Dissertations & Theses
With over 2.3 million records, the ProQuest Dissertations & Theses (PQDT) database is the most comprehensive collection of dissertations and theses in the world. It is the database of record for graduate research.

The database includes citations of graduate works ranging from the first U.S. dissertation, accepted in 1861, to those accepted as recently as last semester. Of the 2.3 million graduate works included in the database, ProQuest offers more than 1.9 million in full text formats. Of those, over 860,000 are available in PDF format. More than 60,000 dissertations and theses are added to the database each year.

If you have questions, please feel free to visit the ProQuest Web site - http://www.proquest.com - or call ProQuest Hotline Customer Support at 1-800-521-3042.