Average Radiative Capture Cross Sections for 30- and 65-keV Neutrons

Neutron radiative capture cross sections near 30 and 65 keV have been measured for a large number of elements by means of a large liquid scintillator and a pulsed neutron source. The results show definitive even vs odd $A$ effects as well as systematic variations due primarily to effects of nuclear shells. Calculations of the scintillator efficiency for various capture $\gamma$-ray cascade modes are in good agreement with experimental results.