Angular Dependence of Secondary Electron Emission Spectra from a Polycrystalline Au Surface
Bulletin of the American Physical Society
The angle dependence of emitted electron spectra from a polycrystalline Au surface has been measured at several incident electron beam energies. The range of incident energies (~100 eV to 3000 eV) extends from below the first crossover energy, through Emax, to above the second crossover energy. The traditional distinction between secondary electrons (< 50 eV)and backscattered electrons (>50 eV)is found to be inconsistent with our energy- and angle-resolved measurements. We suggest a more “natural” delineation occurs at the local minima of the emission spectra; this feature is studied as a function of incident energy and emission angle. The observed angular dependence of the emitted secondary electrons spectra in the region <50eV does not follow the simple cosine distribution predicted for isotropic (randomized) emission. Nor does the emission spectra >50 eV agree with the Mott scattering cross section for quasi-elastic scattering. Preliminary interpretation of our results suggests that the recent theory and simulation studies may overestimate the occurrence of randomizing collisions of scattered electron in the models of the transport mechanism. This work is supported by the NASA Space Environments and Effects Program.
Jason Kite, JR Dennison and R.E. Davies, “Angular Dependence of Secondary Electron Emission Spectra from a Polycrystalline Au Surface,” Bull. Am. Phys. Soc. 47(1) Part 1, 370 (2002). APS March Meeting, Indianapolis, IN, March 19, 2002.