Akademik Veri Yönetim Sistemi
ANNALS OF NUCLEAR ENERGY, cilt.62, ss.178-183, 2013 (SCI-Expanded)
The thermal neutron cross section (sigma(0)) and the resonance integral cross section (I-0) for the formation of the isomeric state Cs-134m by the Cs-133(n,gamma)Cs-134m reaction were experimentally determined by using an activation method with a single monitor Mn-55. In this study, each of analytical grade MnO2 and Cs2CO3 powders was diluted separately with Al2O3 powder to reduce neutron self-shielding effects, and then they were irradiated with and without a cadmium shield case in an isotropic neutron field of the Am-241-Be neutron source. The activities produced in the samples were measured by a high resolution gamma-ray spectrometry with a calibrated HPGe detector. The necessary correction factors for gamma-ray self-attenuation, true coincidence summing effects, thermal and resonance neutron self-shielding effects, and epithermal spectrum-shape factor were taken into account. The sigma(0) and I-0 values were determined to be sigma(o) = 2.77 +/- 0.14 b and I-0 = 22.8 +/- 1.7 b for the Cs-133(n,gamma)Cs-134m reaction. These results are discussed and compared to the previous measurements and the evaluated data. The present sigma(0) value is close to some of the previously reported experimental and evaluated data within the uncertainty limits. However, the present I-0 value was found to be about 28-51% smaller than other experimentally reported ones appeared in the literature. The measured resonance integral cross section value agrees well only with the newest experimental data obtained by Nakamura et al. (1999) for the Cs-133(n,gamma)Cs-134m reaction. (C) 2013 Elsevier Ltd. All rights reserved.