Investigation of 55Co Levels with the 54Fe (p, γ) 55Co Reaction I. Excitation and Decay Properties of Resonances

The nucleus 55Co has been studied through the reaction 54(p, γ)55Co. The yield curve has been measured in the proton energy range 0.80-2.37 MeV. The resonance bombarding energies and the corresponding 55Co excitation energies of 46 resonances are reported. The Q-value of the reaction has been determined to be 5064.2 ± 0.4 keV. The excitation energies of 34 levels below 5.6 MeV, fed by the resonance states, have been deduced. The gamma-decay of 29 resonances and of the 34 excited states below 5.6 MeV have been investigated, including 17 resonances and nine excited states for which the branching ratios are reported for the first time. Based on the new branching ratios, the revised resonance strength values of 2.6 ± 0.4 and 1.2 ± 0.2 eV are given for the Ep = 1722 and 1887 keV standard resonances, respectively. The relative strengths have been determined for 28 resonances. Using the present resonance strengths and branching ratios the transition probabilities of primary transitions from 14 resonance states have been calculated, including two observed analogue to analogue transitions.

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