Measurements have been made of the ion-fractions of H and 4He backscattered with energies of 25-160 keV from Cu, Au, and Si surfaces which were etched and washed but not atomically clean. The ion-fractions for H range from 0.37 at 25keV to 0.92 at 160 keV, and for 4He from 0.10 at 30keV to 0.58 at 150 keV, depending to a small extent on the target material. Where comparisons can be made the data agree rather closely with results of others for particles traversing thin foils. The data are useful for calibration of an electrostatic analyzer in surface analysis. Plots of ion-fraction against particle velocity show a primary dependence on velocity, as expected, but there is a small difference in slope between the H and He curves. Charge states of particles scattered from surface impurities did not deviate significantly from those of particles scattered from the substrate at the same energy.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Condensed Matter Physics
- Surfaces and Interfaces