Isomeric yield ratios of Pm-148 from the Sm-nat(gamma, x) and the Nd-nat(p, xn) reactions

Abstract

The independent isomeric yield ratios of Pm-148 from the Sm-nat(gamma, x) reaction at the end-point bremsstrahlung energy of 45-64 MeV have been determined using an off-line gamma-ray spectrometric technique at the 100 MeV electron linac of Pohang accelerator laboratory, Pohang, Korea. We also have determined the isomeric yield ratios of Pm-148 from the Nd-nat(p,xn) reactions in the proton energy of 5.08-44.72 MeV by a stacked-foil activation and an off-line gamma-ray spectrometric techniques at the MC-50 cyclotron of the Korean Institute of Radiological and Medical Sciences, Korea. The determined isomeric yield ratios of Pm-148 were compared with literature data and theoretical values estimated by the TALYS 1.4. The present data along with the similar data from literature at other energies shows that the isomeric yield ratio of Pm-148 increases with the excitation energy both in the Sm-nat(gamma, x) and the Nd-nat(p, xn) reactions. The isomeric yield ratios of Pm-148 from the Nd-nat(p, xn) reactions are always higher than those from the Sm-nat(gamma, x) reactions at the same excitation energy, which indicate the role of input angular momentum besides excitation energy.