Main Channels of the Decay of the Giant Dipole Resonance in the ~(20,22)Ne Nuclei and Isospin Splitting of the Giant Dipole Resonance

摘要

Data published in the literature on various photonuclear reactions for the ~(20,22)Ne isotopes and for their natural mixture are analyzed with the aim of exploring special features of the decay of giant-dipole-resonance states in these two isotopes. With the aid of data on the abundances of the isotopes and on the energy reaction thresholds, the cross sections for the reactions ~(20,22)Ne[(γ,n) + (γ,np)] and ~(20,22)Ne[(γ,p) + (γ,np)] are broken down into the contributions from the one-nucleon reactions (Υ,n) and (γ,p) and the contributions from the reactions (γ,np). The cross sections for the reactions ~(20,22)Ne(γ,n)~(19,21)Ne and ~(20,22)Ne(γ,p)~(19,21)F in the energy range E_γ = 16.0-28.0 MeV and the cross sections for the reactions ~(20,22)Ne(γ,np)~(28,20)F in the energy range E_γ = 23.3-28.0 MeV are estimated. The behavior of the cross-section ratio γ = σ(γ,p)/σ(γ,n) for the ~(22)Ne nucleus as a function of energy is analyzed, and the isospin components of the giant dipole resonance in the ~(22)Ne nucleus to the cross sections for various photonuclear reactions are determined on the basis of an analysis of the diagram of the excitation and decay of pure isospin states in the ~(22)Ne nucleus and in nuclei neighboring it, which are members of the corresponding isospin multiplets. The isospin splitting of the giant dipole resonance and the ratio of the intensities of the isospin components are determined to be ΔE = 4.57 ± 0.69 MeV and R = 0.24 ± 0.04, respectively.