Nuclear reactions with ¹¹C and ¹⁴O radioactive ion beams

Thesis/Dissertation · Thu Jan 01 00:00:00 EST 2004

DOI:https://doi.org/10.2172/840236· OSTI ID:840236

Guo, Fanqing ^[1]

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1. Univ. of California, Berkeley, CA (United States)

Radioactive ion beams (RIBs) have been shown to be a useful tool for studying proton-rich nuclides near and beyond the proton dripline and for evaluating nuclear models. To take full advantage of RIBs, Elastic Resonance Scattering in Inverse Kinematics with Thick Targets (ERSIKTT), has proven to be a reliable experimental tool for investigations of proton unbound nuclei. Following several years of effort, Berkeley Experiments with Accelerated Radioactive Species (BEARS), a RIBs capability, has been developed at the Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. The current BEARS provides two RIBs: a ¹¹C beam of up to 2x10⁸ pps intensity on target and an ¹⁴O beam of up to 3x10⁴ pps intensity. While the development of the ¹¹C beam has been relatively easy, a number of challenges had to be overcome to obtain the ¹⁴O beam. The excellent ¹¹C beam has been used to investigate several reactions. The first was the ¹⁹⁷Au(¹¹C,xn)^208-xnAt reaction, which was used to measure excitation functions for the 4n to 8n exit channels. The measured cross sections were generally predicted quite well using the fusion-evaporation code HIVAP. Possible errors in the branching ratios of ?? decays from At isotopes as well as the presence of incomplete fusion reactions probably contribute to specific overpredictions. ¹⁵F has been investigated by the p(¹⁴O,p)14O reaction with the ERSIKTT technology. Several ¹⁴O+p runs have been performed. Excellent energy calibration was obtained using resonances from the p(¹⁴N,p)¹⁴N reaction in inverse kinematics, and comparing the results to those obtained earlier with normal kinematics. The differences between ¹⁴N+p and ¹⁴O+p in the stopping power function have been evaluated for better energy calibration. After careful calibration, the energy levels of 15F were fitted with an R-matrix calculation. Spins and parities were assigned to the two observed resonances. This new measurement of the ¹⁵F ground state supports the disappearance of the Z = 8 proton magic number for odd Z, T_z=-3/2 nuclei. It is expected that future work on proton-rich nuclides will rely heavily on RIBs and/or mass separators. Currently, radioactive ion beam intensities are sufficient for the study of a reasonable number of very proton-rich nuclides.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 840236
• Report Number(s): LBNL-56744; R&D Project: 464501; TRN: US0501872
• Resource Relation: Other Information: TH: Thesis (Ph.D.); Submitted to the UNIVERSITY OF CALIFORNIA, BERKELEY, CA (US); PBD: 9 Dec 2004
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
BRANCHING RATIO
CROSS SECTIONS
ENERGY LEVELS
EXCITATION FUNCTIONS
GROUND STATES
INCOMPLETE FUSION REACTIONS
MAGIC NUCLEI
NUCLEAR MODELS
NUCLEAR REACTIONS
R MATRIX
RADIOACTIVE ION BEAMS
RESONANCE SCATTERING
STOPPING POWER
NUCLEAR REACTIONS CRABON-11 OXYGEN-14 RADIOACTIVE ION BEAMS FLUORINE-15