Systematics of Photoneutron Reactions

Properties of the giant dipole resonances for ($\gamma , n$) reactions have been measured for 14 singly-isotopic elements distributed throughout the range of $z$ values. Systematics are reported for the behavior of the integrated cross sections, the energies at which the dipole resonances attain a maximum cross section, the values of the cross sections at these energies, and the widths of the resonances. Anomalously narrow widths are reported for elements with neutron numbers in the vicinity of the magic numbers.