A study of the (α, 2α) reaction on ¹²C, ¹⁶O, ²⁶Mg and ²⁸Si at E[subscript alpha] = 70 MeV

The (α, 2α) reaction on ¹²C, ¹⁶O, ²⁶Mg and ²⁸Si has been studied in a kinematically complete experiment at α-particle bombarding energy of 70 MeV. Energy and angular correlations between the two outgoing α-particles were obtained by measuring the energies of these two particles in coincidence. Both quasi-elastic α-α scattering and two step sequential process contributions to the (α, 2α) reaction cross sections were observed. The experimental results were compared to calculations based on the Plane Wave Impulse Approximation (PWIA) with a cut-off radius and Harmonic Oscillator wave functions for the relative motion of the bound α-cluster. Significant distortion effects were observed which could not be explained with the PWIA, but some of the gross features in the reaction cross section were reproduced by this approximation