Independent isomeric yield ratios of Nb-95m,Nb-g in the Mo-nat(gamma, pxn) and Zr-nat(p, xn) reactions

Abstract

The independent isomeric yield ratios of Nb-95m,Nb-g from the Mo-nat(gamma, pxn) reactions with bremsstrahlung end-point energies of 45, 50, 55, 60, and 70 MeV were determined by an activation and an off-line gamma-ray spectrometric technique at the Pohang accelerator laboratory (PAL), Korea. The isomeric yield ratios of Nb-95m,Nb-g from the Zr-nat(p, xn) reactions were also determined in eight different proton energies within 19.4-44.7 MeV by a stacked-foil activation and an off-line gamma-ray spectrometric technique using the MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences (KIRAMS), Korea. The measured isomeric yield ratios of Nb-95m,Nb-g from the present work and the literature data in the Mo-nat(gamma, pxn) and Zr-nat(p, xn) reactions were compared with the similar literature data in the Mo-nat(p, alpha xn) reactions. It was found that the isomeric yield ratio of Nb-95m,Nb-g increases with projectile energy, which indicate the effect of excitation energy. However, at the same excitation energy, the isomeric yield ratios of Nb-95m,Nb-g in the Zr-nat(p, xn) and Mo-nat(p, alpha xn) reactions are higher than those in the Mo-nat(gamma, pxn) reaction, which indicates the role of input angular momentum. The isomeric yield ratios of Nb-95m,Nb-g in the Mo-nat(gamma, pxn), Zr-nat(p, xn), and Mo-nat(p, alpha xn) reactions were also calculated using computer code TALYS 1.4. The calculated isomeric yield ratios of Nb-95m,Nb-g from three reactions increase with excitation energy. However, in all the three reactions, the calculated values are significantly higher than the experimental data.