Superelastic electron scattering within a magnetic angle changer: Determination of the angular momentum transferred during electron excitation over all scattering angles

By utilizing superelastic electron scattering from laser-excited atoms within a new magnetic angle changing device, the differential cross sections for excitation of atoms by electron impact over the complete scattering geometry are determined for the first time. In the experiments described here, these techniques are combined to reveal the angular momentum transferred to calcium atoms during electron excitation to the 4P11 state, from near 0° to beyond 180°. The experiments are discussed, and results presented for energies of 45 and 55 eV. These results are compared to calculations using a distorted wave Born approximation. © 2007 The American Physical Society.