The fast neutron capture cross section of ${\mathrm{Al}}^{27}$ was measured by observing the 2.3-minute activity of ${\mathrm{Al}}^{28}$ for neutron energies between 10 and 550 kev. Resonances were observed which showed some correlation with scattering resonances so that radiation widths of some of the levels could be estimated. Measurements of activation cross sections were also carried out for F, V, ${\mathrm{Cu}}^{65}$, Ag, I, ${\mathrm{In}}^{115}$, and Au.

• Received 23 June 1950

DOI:https://doi.org/10.1103/PhysRev.80.145