Sputtering Induced by Ar^q+ Impact on Nb Surface

The relative sputtering yield induced by highly charged Ar^q+ impacting on Nb surface is investigated. The yield increases drastically as the incidence angle increases. A formula Y=A*tan^B(θ)+C, developed from classical sputtering theory, fits well with the yield. By analysing a series of coefficients A and C extracted by curve fitting, the results demonstrate the presence of a synergy of the linear cascade collision and potential energy deposition.