Akademik Veri Yönetim Sistemi
ANNALS OF NUCLEAR ENERGY, cilt.63, ss.199-204, 2014 (SCI-Expanded)
The thermal neutron cross section and the resonance integral for the Gd-158(n, gamma)Gd-159 reaction were measured by the activation method with using the Mn-55(n, gamma)Mn-55 monitor reaction. The analytical grade MnO2 and Gd2O3 were mixed separately with Al2O3 powder to reduce both thermal and epithermal neutron self-shielding effects. Then, they were irradiated with and without a cadmium shield box in an isotropic neutron field provided by three Am-241 Be neutron sources. The induced activities in the samples were measured by a p-type HPGe detector. For the irradiated samples, epithermal neutron spectrum-shape factor (alpha), correction factors required for thermal and epithermal neutron self-shielding and for the measured gamma-rays, self-absorption and true coincidence summing effects were taken into account. The thermal neutron cross section was measured to be 2.15 +/- 0.14 b for the Gd-158(n, gamma)Gd-159 reaction. The previously reported experimental data for the thermal neutron cross section are distributed from 0.9 to 3.89 b. According to the definition of Cd cut-off energy at 0.55 eV, the resonance integral cross section was measured as 75.3 +/- 7.0 b. The present resonance integral value agrees with some previously reported experimental and evaluated values for the Gd-158(n, gamma)Gd-159 reaction, e.g. 80 b measured by Van DerLinden et al. (1974), 72.06 b evaluated by JENDL-4.0 (Shibata et al., 2011), 73 b reported by Mughabghab (2006) and Holden (1999). (C) 2013 Elsevier Ltd. All rights reserved.