Die Geschwindigkeitsverteilung von kathodenzerstäubtem Kalium

The differential sputtering ratio (energy spectrum) of polycrystalline potassium sputtered by Ar and Xe ions of 28 keV energy has been measured using surface ionization detection. The spectrum shows a maximum at 0.5 eV and drops to half the maximum value at 2.0 eV. The total sputtering ratio for incident Xe ions is found to be 2.7±1.3 atoms/ion. To check what influence the detector might have on the measured spectrum, different materials and temperatures were used. Below 3 eV the detection probability is energy independent, if the detector is properly heated. Above that energy the measured spectra become uncertain, probably because of the onset of reflexion. Therefore the “focussing energy” of sputtering theory cannot be deduced.