Isomeric yield ratio of 115m,gCd in the 116Cd(γ,n) and 116Cd(n,2n) reactions

Abstract

The isomeric yield ratio (IR) of 115m,gCd in the 116Cd(γ,n) reaction at the bremsstrahlung endpoint energies of 70 and 75 MeV and in the 116Cd(n,2n) reaction at the average neutron energies (<En > ) of 21.4 and 30.1 MeV were measured via an offline γ -ray spectrometric technique. The bremsstrahlung energies were produced by impinging the electron beam energies of 70 and 75 MeV on a thin W-target at the Pohang Accelerator Laboratory, Korea. The neutron beams were obtained from the 9Be(p,n) reaction with the proton energies of 35 and 45 MeV using the MC-50 cyclotron at the Korean Institute of Radiological and Medical Sciences. The IR values at different bremsstrahlung and neutron energies were also calculated from the cross-section values of the TENDL-2019 library based on the TALYS-1.9 code. The theoretical values agreed with the experimental data for the bremsstrahlung endpoint energies but were slightly higher for all neutron energies. The current and literature data showed that in both the 116Cd(γ,n) and 116Cd(n,2n) reactions, the IR value of 115m,gCd increases with the projectile energy, indicating the role of excitation energy. However, the experimental and theoretical IR values at the same excitation energy were significantly higher for the 116Cd(n,2n) reaction than that for the 116Cd(γ,n) reaction, highlighting the role of compound nucleus spin.