Measurement of neutron capture cross-sections and capture γ-ray spectra of ^{161,162,163,164}Dy at 550 keV

The neutron capture cross-sections and capture γ-ray spectra of ^{161,162,163,164}Dy were measured at a neutron energy of 550 keV by using the 3-MV Pelletron accelerator of the Research Laboratory for Nuclear Reactors at the Tokyo Institute of Technology. A neutron time-of-flight method was adopted with a 1,5-ns pulsed neutron source using the ⁷Li(p,n) ⁷Be reaction, and a large anti-Compton NaI(Tl) γ-ray spectrometer was used. A pulse-height weighting technique was applied to the observed capture γ-ray pulse-height spectra to derive the capture yields. The measured capture cross-sections were 0.221 ± 0.016, 0.110 ± 0.007, 0.119 ± 0.008, and 0.037 ± 0.005 (barn) for ¹⁶¹Dy, ¹⁶²Dy, ¹⁶³Dy, and ¹⁶⁴Dy, respectively. The present results were in good agreement with previous measurements. However, the evaluated values of ENDF/B-VI for ^162,164Dy were more than three times higher than our measurements. The capture γ-ray spectra were obtained by unfolding the observed capture γ-ray pulse-height spectra.