Measurement of keV-neutron capture cross sections and capture gamma-ray spectra of 147,148,149,150,152,154 Sm

The neutron capture cross sections and capture gamma-ray spectra of Sm-147, Sm-148,Sm-149,Sm-150,Sm-152,Sm-154 were measured in the neutron energy regi on of 10 to 90 keV and at 550 keV. A neutron time-of-flight method was adop ted with a 1.5-ns pulsed neutron source by the Li-7(p, n)Be-7 reaction and with a large anti-Compton NaI(T1) gamma-ray spectrometer. A pulse-height we ighting technique was applied to observed capture gamma-ray pulse-height sp ectra to derive capture yields. The capture cross sections were obtained wi th the error of about 5% by using the standard capture cross sections of (1 97) Au. The present results were compared with the evaluated values of JEND L-3.2 and previous measurements. The capture gamma-ray spectra were obtaine d hy unfolding the observed capture gamma-ray pulse-height spectra. An anom alous shoulder was clearly observed around 3 MeV in the gamma-ray spectra o f Sm-150.152,Sm-154, and the energy position of the shoulder was consistent with the systematics obtained in our previous work.