Akademik Veri Yönetim Sistemi
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, cilt.550, sa.3, ss.626-636, 2005 (SCI-Expanded)
The thermal neutron cross-section (sigma(0)) and the resonance integral (10) of the reaction Dy-164(n,gamma) Dy-165 were measured by the activation method, using Mn-55(n,gamma) Mn-55 monitor reaction as a single comparator. The diluted MnO2 and Dy2O3 powder samples within and without a cylindrical Cd shield case were irradiated in an isotropic neutron field obtained from the Am-241-Be neutron sources, moderated with paraffin wax. The gamma-ray spectra from the irradiated samples were measured by high-resolution gamma-ray spectrometry with a calibrated n-type Ge detector. The necessary correction factors for gamma-ray attenuation, thermal neutron and resonance neutron self-shielding effects and epithermal neutron spectrum shape factor (a) were taken into account in the determinations. The thermal neutron cross-section for Dy-164(n,gamma) Dy-165 reaction studied has been determined to be 2672 +/- 104 b at 0.025 eV. This result has been obtained relative to the reference thermal neutron cross-section value of 13.3 +/- 0.1 b for the 55 Mn(n,gamma) 56 Mn reaction. For the thermal neutron cross-section, most of the experimental data and evaluated one in ENDF/B-VI, in general, are in good agreement with the present result. The resonance integral has also been measured relative to the reference value of 14.0 +/- 0.3 b for the Mn-55(n,gamma) Mn-56 monitor reaction using a 1/k(1+alpha) epithermal neutron spectrum of the Am-241-Be neutron source. By defining Cd cut-off energy 0.55 eV, the resonance integral obtained was 527 +/- 89 b. The existing experimental and evaluated data for the resonance integral are distributed from 335 to 820 b. The present resonance integral value agrees with some previously reported values, 520 b by Holden, 505 b by Simonits et al. and 575 +/- 100 b by Heft, within the limits of error. (c) 2005 Elsevier B.V. All rights reserved.