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Isobaric analogue resonances in the 56 Fe(p,y)57Co reaction

University of British Columbia

The excitation function for the reaction ⁵⁶F(p,y)⁵⁷Co has been measured from 1200 - 3000 KeV proton energy using enriched ⁵⁶Fe targets. Gamma-ray spectra were measured using Ge(Li) and NaI(T£) detectors. The resonance strength, 10^, has been determined for the studied resonances. Gamma-ray angular distributions were measured using NaI(T£) detectors. In the energy region between 1240 and 1272 KeV, the gamma-ray angular distributions were measured using the Ge(Li) detector. Gamma-ray angular distributions have been measured for resonances corresponding to excitation energies in ⁵⁷Co of 7253, 7267, 7272, 7598, 7622, 7641, 7647, 7925, 8192 and 8450 KeV. The-branching ratios, spins and parities of the resonance levels as well as some of the low-lying states in ⁵⁷Co have been established. The reaction Q-value derived from these measurements is Q = 6027 ± 3 KeV. From the gamma-ray spectra and angular distributions which have been studied the levels at 7253, 7267 and 7272 KeV excitation in ⁵⁷Co are identified as the split analogue of the T = 5/2 corresponding to the first bound state in the parent nucleus ⁵⁷Fe at 14 KeV. The group of levels at 7622, 7641 and 7647 KeV excitation in ⁵⁷Co are believed to form the split analogue of the 367 KeV bound state in 57Fe. The level at 8450 KeV excitation is tentatively identified as the isobaric analogue state of T = 5/2 corresponding to the 1196 KeV bound state in ⁵⁷Fe. The absence of the isobaric analogue resonance corresponding to the ground state in ⁵⁷Fe is discussed as a result of the present study. A coulomb displacement energy for ⁵⁷Co - ⁵⁷Fe of 8876 ± 6 KeV is deduced from these measurements.

Text

2010-01-22

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http://hdl.handle.net/2429/19055

Physics

University of British Columbia

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