Cross section of low-energy proton radiative capture by intermediate mass nuclei

The cross sections of pγ-reactions on 50Cr, 56Fe, sup(58,60,61)Ni, sup(64,67)Zn and sup(74,77)Se in the proton energy range from 0.6 to 3 Mev have been measured with a view to obtain information about nuclear constants of medium nuclei. The results are analyzed in accordance with the statistical theory of nuclear reactions. The pγ-reaction cross sections were measured by induced radioactivity and instantaneous gamma-radiation methods. The error in determining absolute cross sections did not exceed 15%. Cross sections of the following reactions have been obtained: 50Cr(pγ)51Mn; 56Fe(pγ)57Co; 58Ni(pγ)59Cu; 60Ni(pγ)61Cu; 61Ni(pγ)62Cu; 64Zn(pγ)65Ga; 67Zn(pγ)68Ga; 74Se(pγ)75Br; 77Se(pγ)78Br. It is concluded that the use of the statistical theory for the analysis of pγ-reactions on medium nuclei has permitted to describe the energy dependence of cross sections,, with the exception of fluctuations due to excitation of certain nuclear resonance states at low energies when the state density is small (50Cr, 58Ni, 56Fe). In all the cases the energy relationship for widths of about Esub(γ)5 determined by extrapolating the giant resonance into the energy range from 5 to 10 MeV is preferred