Measurements of neutron capture cross section for 207,208Pb

The neutron capture cross sections for 207,208Pb have been measured in the neutron energy region from 10 to 110 keV. The γ-rays cascaded from a capture state to the ground state or low-lying states of 208,209Pb were observed for the first time, using an anti-Compton Nal(Tl) spectrometer and a TOF method. The observed discrete γ-ray energy spectra enabled us to determine neutron capture cross sections for 207,208Pb with small systematic errors, since we could distinguish γ-ray of 207,208Pb(n,γ) reactions from background γ-ray with use of the γ-ray spectra. The obtained cross sections include both contributions of resonance and direct capture components different from the previous TOF measurements.