Measurement of isomeric yield ratio of 115m,gCd in the 116Cd(γ,n) reaction at the end-point bremsstrahlung energies of 40-75 MeV

The Isomeric Yield Ratio (IYR) of 115m,gCd in the 40, 45, 50, 55, 60, 65, 70 and 75 MeV bremsstrahlung induced reaction of natCd has been determined for the first time by off-line gamma ray spectrometric technique using 100 MeV electron linac at Pohang Accelerator Laboratory (PAL), Pohang, Korea. The IYR of 115m,gCd as a function of bremsstrahlung energy was also calculated theoretically using computer code TALYS 1.6. The experimental IYR in the 116Cd(γ,n)115m,gCd reaction obtained in the present work along with literature data at lower energies are compared with the theoretical value from TALYS and found to be in general agreement. It was observed that the experimental and theoretical IYR of 115m,gCd increases with the increase of end-point bremsstrahlung energy, which shows the effect of excitation energy. It was also seen that the IYR of 115m,gCd increases sharply from the reaction threshold value to end-point bremsstrahlung energy of 18 MeV and thereafter increase slowly. This indicates the role of Giant Dipole Resonance (GDR) besides the effect of excitation energy.