Spectroscopy of 57Co by γ-γ-recoil coincidences with the 40Ca(20Ne, 3 pγ)- reaction and the 55Mn(α,2 nγ)-reaction

High spin of 57Co have been studied with the 40Ca(20 Ne,3 p) and 55Mn(α,n) reactions at 68 MeV and 25 MeV respectively. The first measurement used γγ recoil coincidences with the OSIRIS γ spectrometer and Recoil Filter Detector (RFD). The RFD measured the velocity vector of the fusion evaporation residues; therefore an event by event Doppler correction could be applied with the significant improvement for the γ energy resolution. The analysis of the γγ recoil coincidence spectra resulted in 43 new gγ transitions of energies between 300 keV and 3300 keV that are assigned to 57 Co and established 25 new excited states. Also a DCO analysis has been performed on the present data, however it does not lead to an unambiguous spin assignment for most states as the measured DCO - ratio is often compatible with different spin combination. The reaction 55 Mn (α, 2 n) was studied with the compact setup of two Ge detectors. Singles γ and γγ coincidence spectra were measured. Mainly low spin states were populated, and 26 previously known γ-transitions as well as 21 excited states of 57 Co have been confirmed. This contribution result are presented on 57 Co, nucleus with two neutrons and one proton hole. (author). 8 refs, 1 fig