Isomeric yield ratios in the photoproduction of Mn-52m,Mn-g from natural iron using 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung

Abstract

The isomeric yield ratios for the Fe-nat(gamma,xn1p)Mn-52m,Mn-g reactions have been measured by the activation and the gamma-ray spectroscopic methods at 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung energies. The high purity natural iron foils in disc shape were irradiated with uncollimated bremsstrahlung beams of the 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. In order to improve the accuracy of the experimental results the necessary corrections were made in the gamma activity measurements and data analysis. The obtained isomeric yield ratios for the Fe-nat(gamma,xn1p)Mn-52m,Mn-g reactions at 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung energies are 0.27 +/- A 0.03, 0.33 +/- A 0.04, 0.34 +/- A 0.04, and 1.25 +/- A 0.15, respectively. The present results at 50-, 60-MeV, and 2.5-GeV bremsstrahlung energies are the first measurements. We found that the isomeric yield ratio of the Fe-nat(gamma,xn1p)Mn-52m,Mn-g reaction depends on the incident bremsstrahlung energy and the mass difference between the product and the target nucleus when we compared the present results with other experimental data at different energies.