Internal Conversion of Neutron Captureγ-Rays

Prompt internal conversion electron lines resulting from neutron capture in ${}_{48}{}^{}{}_{}{}^{}\mathrm{Cd}_{}^{113}{}_{}{}^{}$, ${}_{62}{}^{}{}_{}{}^{}\mathrm{Sm}_{}^{149}{}_{}{}^{}$, ${}_{64}{}^{}{}_{}{}^{}\mathrm{Gd}_{}^{\mathrm{odd}}{}_{}{}^{}$, ${}_{66}{}^{}{}_{}{}^{}\mathrm{Dy}_{}^{164}{}_{}{}^{}$, and ${}_{80}{}^{}{}_{}{}^{}\mathrm{Hg}_{}^{199}{}_{}{}^{}$ have been observed. Their energies were measured in a 180° focusing, constant magnetic field, film recording $\beta$-ray spectrograph. The spectrograph was placed in a neutron beam from the Argonne heavy water reactor in such a way that the source underwent bombardment during recording. In some cases $K$, $L$, and $M$ lines were observed. Each element except mercury exhibited two strongly converting capture $\gamma$-ray states from a single isotope.