Radiochemical study of the 12C(3He, 7Be) reaction mechanism at 30 MeV

The excitation function for the 12C(3He, 7Be) reaction has been measured up to incident energies of 31 MeV, and the 7Be recoil properties determined in a series of catcher foil experiments at 30 MeV. Based on the different recoil properties of 7Be formed by each of four different mechanisms, the contribution of each has been estimated. At 30 MeV the predominant mode of 7Be formation is through sequential decay of the compound nucleus 15O*→11C*+α1 →7Be+α2+α1 (approx. =39 mb). This is followed in importance by the direct n pickup reaction to certain excited states in 11C followed by α-particle emission 11C*→7Be+α. The direct α-particle pickup reaction and compound nucleus evaporation of 7Be have smaller cross sections (approx. =1 mb and <1 mb, respectively)