Low energy super-elastic scattering studies of calcium over the complete angular range using a magnetic angle changing device

Super-elastic scattering processes can be considered as the ‘time reversal’ of electron–photon coincidence measurements, with the advantage that data are accumulated thousands of times faster. This allows a far more extensive and accurate study of electron excitation of atoms which can also be excited using laser radiation. The application of a newly invented magnetic angle changing (MAC) device to these experiments has allowed the complete scattering geometry to be accessed for the first time, and experimental methods adopted in these new experiments are discussed here. Data are presented for excitation of the 4¹P₁ state of calcium by electron impact at scattering angles from near 0 degrees to beyond 180 degrees, with incident energies of 45 eV and 55 eV. The results are compared to the DWBA theory of Stauffer and colleagues, with generally excellent agreement.