Measurement of isomeric yield ratios for Nb-93(gamma,4n)Nb-89m,Nb-g and Mo-nat(gamma,xn1p)Nb-95m,Nb-g reactions with 50-, 60-, and 70-MeV bremsstrahlung

Abstract

We measured the isomeric yield ratios for the photonuclear reactions of Nb-93(gamma,4n)Nb-89m,Nb-g and Mo-nat(gamma,xnp)Nb-95m,Nb-g by using the activation method. The high-purity Nb-93 and Mo-nat metallic foils in disc shape were irradiated with uncollimated bremsstrahlung beams of 50-, 60-, and 70-MeV generated from an electron linear accelerator in Pohang Accelerator Laboratory. The induced activities in the irradiated foils were measured by the high-resolution gamma-ray spectrometry with a calibrated high-purity Germanium (HPGe) detector coupled to a PC-based 4 K multichannel analyzer. The reaction Nb-93(gamma,4n)Nb-89m,Nb-g was studied for the first time which has no comparable literature data. The result of Nb-95m,Nb-g isomeric pair was measured based on (gamma,p), (gamma,np), and (gamma,2np) reactions which is the first measurement at the intermediate energy region of 50-70-MeV with a Mo-nat target.