Resonant low energy electrons and their impact on sampling depth during backscatter-electron ms̈sbauer spectroscopy

摘要: Collection of low energy electrons (< 15 eV) during Conversion Electron Mossbauer Spectroscopy (CEMS) provides enhanced surface sensitivity. To identify and quantify the potential sensitivity provided by these species, spectra were collected from a 92.8% enriched 57Fe foil using retarding field analyzers in conjunction with spiraltron electron multipliers. Both resonant nonresonant count rates decrease as much 50% at 10 eV bias establishing that large fraction is produced CEMS. Surface enhancement due to was identified observing inherent signal-to-background ratios samples topmost 1.0 nm chemically labeled. The area ratio overlayer substrate 1.43 0 while decreased 0.72. By vacuum evaporating 5.0 copper coating on sample, near complete attenuation excess achieved. These results suggest some below are formed primary products electronic relaxation following nuclear decay they not result straggling or other scattering phenomena. Low signals appear useful for science applications permitting information monolayers be readily distinguished those arising deeper within solid.