Photonuclear Reactions of Gallium and Arsenic with 70-Mev Bremsstrahlung

Radiochemical techniques were utilized in the measurement of yields of photonuclear reactions induced by 70-Mev bremsstrahlung in gallium and arsenic targets. For As targets the yields of ${\mathrm{As}}^{74}$, ${\mathrm{Ga}}^{73}$, ${\mathrm{Ga}}^{72}$, ${\mathrm{Ga}}^{68}$, ${\mathrm{Zn}}^{69}$, and ${\mathrm{Zn}}^{69m}$ were determined. In the gallium targets the yields of ${\mathrm{Zn}}^{69}$, ${\mathrm{Zn}}^{69m}$, ${\mathrm{Ni}}^{65}$, and ${\mathrm{Co}}^{61}$ were measured. The integrated cross sections for the indicated photonuclear reactions were estimated from the yields. The integrated cross sections of five ($\gamma , 3p3n$) processes were compared. The relative yields of the ${\mathrm{Zn}}^{69}$ isomeric pair depended upon the process of formation.