An Investigation of the Compound Nuclei ⁷Li and ⁷Be

Citation

Spiger, Robert John (1967) An Investigation of the Compound Nuclei ⁷Li and ⁷Be. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/75XC-EF29. https://resolver.caltech.edu/CaltechETD:etd-10042002-143530

Abstract

The differential elastic scattering cross section has been measured for the scattermg of ³He from ⁴He and the scattering of ⁴He from tritium. Incident particle energies of 5 to 18 MeV and 4 to 18 MeV, respectively, were used. Gas targets were used and solid state silicon detectors were employed to detect the scattered particles. Data were also obtained for the reactions ⁴He³He,p)⁶Li, ⁴He³He,p¹)⁶Li*, ³H(α,n)⁶Li and ³H(α,n¹)⁶Li*. Levels are seen at 4.65, 6.64, 7.47 and 9.7 MeV in ⁷Li and at 4.57, 6.73, 7.21 and 9.3 MeV in ⁷Be. A phase shift analysis suggests assignments of 7^-/2 and 5^-/2 for the two lower levels in ⁷Li, confirms the 5^-/2 assignment of the 7.47 level and suggests a 7^-/2 assignment for the new level at 9.7 MeV. Similarly in ⁷Be, the assignment of 7^-/2 and 5^-/2 for the lower two levels is reconfirmed and an assignment of 7^-/2 is suggested for the new level at 9.3 MeV. The reduced widths for α and nucleon emission were determined by fitting the phase shifts near each level with a single and/or double level formula from the R-matrix formalism of Lane and Thomas (1958). The results of the analysis are discussed and compared with predictions of some recent nuclear model calculations.

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