The effect of oxides on PIXE measurements

The presence of oxides on metallic samples used for PIXE analysis affects quantitative measurements. This effect has been calculated based on thick target analysis on layers of different compositions. The ratio of oxidized metal yield to clean metal yield is seen to depend on proton energy and on oxide thickness. Calculations are presented for oxides of Al, Si, Fe, and Cu, and applied to experimental data on Si. The method may be applied to measuring thicknesses of oxides of known stoichiometry.