$\alpha$-Clusters in $^{16}$O

There has been previous experimental evidence of an interesting four $\alpha$ linear configuration in $^{16}$O [1]. At the Notre Dame FN Tandem Accelerator we explored the reaction of $^ {12}$C+$\alpha$$\rightarrow$$^{16}$O$\rightarrow$$^{8}$Be+$^{8} $Be. An array of Si strip detectors was set up at the forward angles to observe the final individual four $\alpha$- particles [2]. Afterwards, from the $^{8}$Be+$^{8}$Be channel, an excitation curve was constructed for an energy range of 12- 20 Mev. In addition a $^{12}$C ($\alpha,n$) transfer reaction was carried out to study the same $\alpha$-cluster structure in $^{16}$O, which required additional neutron detectors placed at the backward angles. Interesting $\alpha$-cluster levels detected in the two reactions will be analyzed in detail (such as the angular distribution). The preliminary results on the existence of the linear $\alpha$ structure will be presented.\\[4pt] [1] P. Chevallier {\it et al.}, Phys. Rev. {\bf 160}, 827 (1967).\\[0pt] [2] P.J. Haigh {\it et al.}, J. Phys. G: Nucl. Part. Phys. {\bf 37}, 035103 (2010).