A new experimental setup for measuring particle-particle angular correlations with a position sensitive detector is presented. The method was investigated using the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^{12}{}_{}{}^{}\mathrm{C},{\alpha }_1){}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}\left({\alpha }_2\right){}_{}{}^{16}{}_{}{}^{}\mathrm{O}$. The first $\alpha$ particle was detected in a telescope located at 0°, whereas the second one was measured in a 55-mm-long position-sensitive detector covering angles between 30 and 110°. From the measured correlation functions the spins of the intermediate ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ states can be determined uniquely. A new $J^{\pi }=7^{-}$ state was found at an excitation energy of 16.5 ± 0.3 MeV.

• Received 19 February 1971

DOI:https://doi.org/10.1103/PhysRevC.4.10