Neutron Total and Capture Cross-Section Measurements of 155gd and 157gd in the Thermal Energy Region with the Li-glass Detectors and NaI(Tl) Spectrometer Installed in J-PARC·MLF·ANNRI

Neutron total and capture cross-section measurements of Gd-155 and Gd-157 were performed with Li-glass detectors and a NaI(TI) spectrometer in the ANNRI at the MLF of the J-PARC. The neutron total cross sections were determined in the energy region from 5 to 100 meV, and those at the thermal neutron energy were obtained to be 59.4 +/- 1.7 and 251.9 +/- 4.6 kilobarn for Gd-155 and Gd-157, respectively. The neutron capture cross sections were determined in the energy region from 3.5 to 100 meV with an innovative method, and those at the thermal energy were obtained as 59.0 +/- 2.5 and 247.4 +/- 3.9 kilobarn for Gd-155 and Gd-157, respectively. The present total and capture cross sections agree well within the standard deviations. The results for Gd-155 were found to be consistent with the values in JENDL-4.0 and the experimental data given by Moller et al., Mastromarco et al. and Leinweber et al. Those for 1s Gd agreed with the evaluated data in JENDL-4.0 and the experimental data by Moller et al. and Mastromarco et al. However, they disagree (11% larger) with the experimental result by Leinweber et al.