Independent isomeric-yield ratio of Nb-89m,Nb-g from Nb-93(gamma, 4n), Zr-nat(p, xn), and Y-89(alpha, 4n) reactions

Abstract

The independent isomeric-yield ratios of (89m,g) Nb for the Nb-93(gamma, 4n) (89m,g) Nb reaction with brems-strahlung energies of 45-, 50-, 55-, 60-, and 70- MeV were measured by the activation and the off- line gamma-ray spectrometric technique at 100 MeV electron linac of the Pohang accelerator laboratory. The isomeric- yield ratios of Nb-89m,Nb-g for the Zr-nat( p, xn) Nb-89m,Nb-g and the Y-89(alpha, 4n) Nb-89m,Nb-g reactions were measured by using a stacked- foil activation technique with the proton energies of 19- 45 MeV and alpha energies of 38.9-, 40.5-, and 42.5- MeV at the MC- 50 cyclotron of Korea Institute of Radiological and Medical Sciences. The measured isomeric- yield ratio of Nb-89m,Nb-g from the Nb-93(gamma, 4n), nat Zr( p, xn), and Y-89(alpha, 4n) reactions were compared with the similar literature data in the Y-89(He-3, 3n) reaction. It was found that the isomeric yield ratio of Nb-89m,Nb-g increases with projectile energy, which indicate the effect of excitation energy. However, for the similar compound nucleus with the same excitation energy, the isomeric- yield ratios of Nb-89m,Nb-g in the Y-89(alpha, 4n) and Y-89(He-3, 3n) reactions are higher than those in the 93 Nb( c, 4n) and nat Zr( p, xn) reactions, which indicates the role of input angular momentum. The isomeric- yield ratios of (89m,g) Nb in the Nb-93(gamma, 4n), Zr-nat( p, xn), 89 Y( alpha, 4n), and Y-89(He-3, 3n) reactions were also calculated theoretically using computer code TALYS 1.4. The theoretical isomericyield ratios of Nb-89m,Nb-g from four reactions increase with excitation energy. However, the theoretical value are significantly higher than the experimental data in the Nb-93(gamma, 4n) and Zr-nat(p, xn) reactions but slightly lower or comparable in the Y-89(alpha, 4n) rand Y-89(He-3, 3n) reactions.