Akademik Veri Yönetim Sistemi
ANNALS OF NUCLEAR ENERGY, cilt.34, sa.3, ss.188-193, 2007 (SCI-Expanded)
This study implies that Mn-55(n,gamma)Mn-55 monitor reaction may be a convenient alternative comparator for the activation method and thus, it was used for the determination of thermal neutron cross section (TNX) and the resonance integral (RI) of the reaction Sm-152(n,gamma)Sm-153. The samples of MnO2 and Sm2O3 diluted with Al2O3 powder were irradiated within and without a cylindrical 1 mm-Cd shield case in an isotropic neutron field obtained from the Am-241-Be neutron sources. The gamma-ray spectra from the irradiated samples were measured by high resolution gamma-ray spectrometry with a calibrated n-type Ge detector. The correction factors for gamma-ray attenuation, thermal neutron and resonance neutron self-shielding effects and epithermal neutron spectrum shape factor (alpha) were taken into account in the determinations. The thermal neutron cross section for Sm-152(n,gamma)Sm-153 reaction has been determined to be 204.8 +/- 7.9 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 Mn-55(n,gamma)Mn-56 reaction. For the TNX, most of the experimental data and evaluated one in JEFF-3.1, ENDF/B-VI, JENDL 3.3 and BROND 2.0, in general, agree well with the present result. The RI value for Sm-152(n,gamma)Sm-153 reaction has also been determined to be 3038 +/- 214 b, relative to the reference value of 14.0 +/- 0.3 b for the Mn-55(n,gamma)Mn-56 monitor reaction, using a I/E1+alpha epithermal neutron spectrum and assuming Cd cut-off energy of 0.55 eV. In surveying literature, the existing experimental and evaluated data for the R1 values are distributed from 1715 to 3462 b. However, when the Cd cut-off energy is defined as 0.55 eV, the present RI value agrees with some previously reported RI values, 3020 +/- 163 b by Simonits et a]., 3141 +/- 157 by Van Der Linden et al., and 2962 +/- 54 b by Kafala et al., within the limits of error. (c) 2006 Elsevier Ltd. All rights reserved.