Proton-Gamma-Ray Coincidence Counting with Cyclotron Bombardment

A technique is given for studying associations between protons and gamma-rays emitted when a target is bombarded with particles from the cyclotron. A description is included of the theoretical considerations involved and of the apparatus developed. The results on the ${\mathrm{Al}}^{27}(\alpha ,p){\mathrm{Si}}^{30}$ reaction indicate that no gamma-rays accompany the end group of protons, while other groups exhibit coincidences. The coincidence rate increases with excitation energy. This may be due to cascade transitions giving more quanta, or to increased sensitivity for higher energy quanta. The fourth group observed with zero-degree bombardment is shown to be a composite of knock-on protons and protons from the reaction. A brief proton group study is included with $Q$ values in essential agreement with previous work.