[en] High T_c superconducting Y-Ba-Cu-O sample is bombarded by 20 keV Ar⁺ ion beam. The composition of the bulk sample before and after sputtering is analyzed by means of PIXE method. The composition change at the surface of the bulk sample after sputtering is presented and discussed. The particles sputtered from the surface of the bulk sample are collected on a substrate of silicon. The composition of the film formed on the substrate is determined by PIXE (Proton induced X-ray emission) and RBS (Rutherford Backscattering Spectroscopy) combined with ¹⁶O(α, α)¹⁶O nuclear resonance scattering