(γ, 2n), (γ, αn) and (γ, α2n) reactions on ⁶³Cu and the decay of ⁵⁸Co

Abstract

The photonuclear yield of the ⁶³Cu(γ, αn)⁵⁸Co and the ⁶³Cu(γ, α2n)⁵⁷Co reactions relative to the yield of the ⁶³Cu(γ, 2n)⁶¹Cu reaction has been measured with thick target bremsstrahlung at end-point energies of 30, 40 and 50 MeV. The ⁵⁷Co and ⁵⁸Co were identified by carrier chemistry separation and by gamma-ray energy and half-life measurements. The possibility of competing reactions which could also produce ⁵⁷Co or ⁵⁸Co is discussed.

The energy and relative intensity of the gamma rays emitted in the decay of ⁵⁸Co were measured as 811.07±0.2 keV (1000), 863.83±0.5 keV (8.1±0.3) and 1673.1±2 keV (5.7±0.3). The branching ratio obtained for the 1674.8 keV state in ⁵⁸Fe is (58.7±1.6) % for the 2⁺ → 2⁺ transition. The results are compared with previous measurements for the decay of ⁵⁸Co.