The angular distribution of elastically scattered electrons, its modeling and computed effect on collector performance

Summary form only given. It is known that the suppression of secondary electron emission significantly improves the performance of electron beam collectors. However, a complete analysis of the effects of secondary emission on collector performance has not been possible because of the lack of quantitative data on secondary electrons. The measurements of the angular distribution of elastically scattered secondary electrons from surfaces of polished copper, ion-textured copper, and isotropic (POCO) graphite will be presented. An electron source, with an energy ranging from 100 to 3000 eV and a spot size of less than 1 mm, was directed the target. The angle of incidence for the source was varied from normal to grazing incidence in 2 or 3 degree increments. At each angle of incidence, secondary electrons within 2 to 20% of the energy of the incident beam were measured throughout the half-sphere above the target surface in 1 degree increments.