Yield curves were measured for one neutron emission in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$, ${}_{}{}^{35}{}_{}{}^{}\mathrm{Cl}$, and ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}$, and for two neutron emission in ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$, with target stacks which were bombarded by electrons. The results were analyzed to compare the yields from the direct effect of the electrons with those resulting from bremsstrahlung from the electrons. The analysis was carried out with the virtual photon method in the plane-wave Born approximation and the distorted-wave Born approximation (DWBA). Agreement with DWBA predictions is obtained assuming photoabsorption through $E1\mathrm{}$ transitions.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$, ${}_{}{}^{35}{}_{}{}^{}\mathrm{Cl}$, ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}$; ($\gamma , n$), ($e, e^{\prime }, n$); ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$, ($\gamma , 2n$), ($e, e^{\prime }, 2n$); $E=16-39\mathrm{}$ MeV; measured $\frac{{\sigma }_{\gamma }\mathrm{}\left(E\right)\mathrm{}}{{\sigma }_e\mathrm{}\left(E\right)\mathrm{}}$; DWBA virtual photon spectra analysis; deduced photoabsorption $\lambda$.

• Received 7 October 1974

DOI:https://doi.org/10.1103/PhysRevC.11.1083