Spectroscopic study of 55Co via the 54Fe(τ, d) 55Co and 54Fe(τ, dp̃) 54Fe reactions

Abstract

The 54Fe(τ, d) 55Co reaction has been studied at 25 MeV incident energy with a split-pole spectrometer. About one hundred levels have been observed in 55Co up to 10 MeV excitation energy. Angular distributions have been measured and analyzed with DWBA and Gamow functions as form factors for unbound levels. The 54Fe(τ,dp̃) 54 reaction has been investigated at 24 MeV incident energy. The angular distributions of the emitted protons were measured in coincidence using method 2 of Litherland and Ferguson, with 0 detection of deuteron groups. Spins, population parameters, branching ratios and proton partial widths for the transitions to the ground and excited states of 54Fe were determined from the analysis of the angular correlation data. The results of these two experiments provide a large number ofspectroscopic properties of unbound proton states and in particular of analog states of 55Fe low-lying levels. The IAS of the 3 2 − ground state of 55Fe is observed to be split between two individual levels. The amplitude of neutron coupling to the first 2 + excited state of 54Fe is obtained for the lg 9 2 and 2 d 5 2 low-lying parent statfes in 55Fe. summed spectroscopic factors and the centroid energies of the proton states in 55Co are obtained. A comparison is made with previous (τ, d), (d, p) and (p, p) results.