Low Energy Diffuse Scattering Electron Spin Polarization Analyzer
John Unguris, Daniel T. Pierce, Robert Celotta
A new, compact (approximately fist sized), efficient electron-spin analyzer is described. It is based on low-energy (150 eV) diffuse scattering from a high-Z target, for example, an evaporated polycrystalline Au film opaque to the incident electron beam. By collecting a large solid angle of scattered electrons, a figure of merit S2I/I0=10-4 is achieved with an analyzing power S=0.11. The figure of merit degrades only marginally (<10%) for beams with an energy width of 40 eV or after one month of operation at 10-8 Torr. The electron optical acceptance is of order 100 mmu2^ sr eV. The details of the design and construction are discussed and its performance is compared to six other spin analyzers. Illustrative results are presented from an application to scanning electron microscopy with polarization analysis (SEMPA) to image magnetic microstructure.