Akademik Veri Yönetim Sistemi
ANNALS OF NUCLEAR ENERGY, cilt.62, ss.274-279, 2013 (SCI-Expanded)
Thermal neutron cross section and resonance integral for the Nd-148(n,gamma)Nd-149 reaction have been measured by the activation method using Mn-55 monitor. The analytical grade MnO2 and Nd2O3 mixed with Al2O3 powder samples were irradiated in an isotropic neutron field of the Am-241-Be neutron source with and without a Cd-shield case. The activities produced in the samples were measured by a high resolution gamma ray spectrometry with a calibrated n-type Ge detector. The necessary correction factors for gamma ray self-attenuation, true coincidence summing effects, thermal, resonance neutron self-shielding effects and epithermal spectrum-shape factor were taken into account. Thermal neutron cross section and resonance integral for the Nd-148(n,7)Nd-149 reaction were obtained relative to the reference values, sigma(0) = 13.3 +/- 0.1 b and I-0 = 14.0 +/- 0.3 b for the Mn-55(n,gamma)Mn-56 reaction. The thermal neutron cross section was measured to be 2.51 +/- 0.13 b, and according to the definition of Cd cut-off energy at 0.55 eV, the resonance integral cross section was obtained to be 14.6 +/- 1.3 b for the Nd-148(n,gamma)Nd-149 reaction. These results are discussed and compared with previous measurements and the evaluated data. Thermal neutron cross section for Nd-148(n,gamma)Nd-149 reaction is in good agreement with some experimental results and the evaluated data in JENDL-3.3 and JEFF-3.1.1. The existing experimental and evaluated data for the resonance integral are distributed from 10.5 to 48 b and the discrepancies between present result and some of old experimental data is within about 3-28%. (C) 2013 Elsevier Ltd. All rights reserved.