The γ-ray decay properties of analogue states of 55Fe excited in the reaction [formula omitted

Abstract

Gamma-ray angular distribution, polarization and resonance strength measurements have been carried out on resonances observed in the reaction 54Fe(p, γ) 55Co at proton energies of 1803 and 1887 keV. These resonances at excitation energies of 6833 and 6916 keV in 55Co have J π = ( 3 2 −) and 5 2 − and resonance strengths of (2J + 1) Γ γΓ p Γ = 0.98 and 0.45 eV respectively. These resonance states have been identified as analogues of the 2050 keV ( J π = 3 2 − ) and 2144 keV ( 5 2 − ) states in 55Fe. A state at 4722 keV ( 3 2 − ) has been identified as the analogue of the ground state of 55Fe. Transition probabilities for γ-rays de-exciting these analogue states are examined. Although no strong analogue-antianalogue transitions from the resonance levels are observed there are strong transitions between the analogue states and also from the analogue of the 55Fe ground state to a T = 1 2 state in 55Co.