This experimental research program is aimed at studies of electron-impact ionization of atomic helium. One experiment will measure electron angular distributions of the two electrons, one the incoming electron and one the electron from the ionization, scattered from the atom over a full 360 degrees. Data will be taken in the region of the helium autoionizing states (excited states of atoms that decay by emission of particles rather than light), both on and off resonance. The results are expected to add new insight into a postulated double scattering mechanism. A second experiment will investigate helium autoionization in the presence of a laser field. Ejected electron spectra will be measured which will contain sidebands separated from the normal autoionization peaks by energies equal to integral numbers of the photon energy. The broader impact of the program involves student education.
