Measurement of isomeric yield ratios in the photo-production of Ce-133m,Ce-g;137m,Ce-g from Ce-nat using 55-, 60-, and 65-MeV bremsstrahlung

Abstract

The isomeric yield ratios of Ce-133m,Ce-g and Ce-137m,Ce-g produced from the Ce-nat(gamma,xn) reactions were determined by using the activation and the off-line gamma-ray spectrometric technique with the end-point bremsstrahlung energies of 55-, 60-, and 65-MeV at 100-MeV electron linac of the Pohang accelerator laboratory. The induced activities in the irradiated foils were measured by using an energy- and efficiency-calibrated HPGe detector coupled to a PC based multi-channel analyzer. The necessary corrections were made to improve the accuracy of the experimental results. The experimental results at bremsstrahlung energies of 55-, 60-, and 65-MeV were 0.324 +/- 0.089, 0.331 +/- 0.086, and 0.403 +/- 0.089 for the Ce-133m,Ce-g, and 0210 +/- 0.062, 0.221 +/- 0.061, and 0.262 +/- 0.061 for the Ce-137m,Ce-g, respectively. The present results for Ce-nat(gamma,xn)Ce-133m,Ce-g;137m.g in this energy region were obtained for the first time which has no comparable literature data. The obtained isomeric yield ratios are compared with the calculated values based on the statistical model code TALYS 1.6. (C) 2015 Elsevier B.V. All rights reserved.