Gamma Rays from the Proton Bombardment of Separated Copper Isotopes

The energy spectrum of $\gamma$ rays obtained from the proton bombardment of separated copper isotopes has been measured. It was found by coincidence measurements that the majority of these $\gamma$ rays arise from the capture process when the bombarding energy is held below 2.2 Mev. The thick target cross section for proton capture at 1.9 Mev is found to be 0.1 millibarn. Above 2.2 Mev, excitation of the 0.67-Mev level in in ${\mathrm{Cu}}^{63}$ by either inelastic scattering or Coulomb excitation is observed. Excited level schemes for both ${\mathrm{Zn}}^{64}$ and ${\mathrm{Zn}}^{66}$ have been obtained. The first three levels in ${\mathrm{Zn}}^{64}$ are found to be at 0.97, 2.27, and 3.04 Mev. The scheme for ${\mathrm{Zn}}^{66}$ is essentially the same as that earlier proposed from the decay of ${\mathrm{Ga}}^{66}$.