A method is proposed for measuring high-voltage charging potentials of dielectrics under ion irradiation by shifting the boundary of the bremsstrahlung X-ray spectrum. Since there is no bremsstrahlung output during Xe+ ion irradiation, it was proposed to use a probing electron beam to generate bremsstrahlung X-rays. To eliminate the effect of charge compensation on the surface, the value of the current of the probing probe of electrons was selected. The values of the equilibrium charging potentials of Al2O3 ceramics, Al2O3 sapphire, SiO2, and Teflon are obtained at different ion irradiation energies. The data obtained are compared with the results of spectrometric studies. Keywords: dielectric charging, ion irradiation, FIB-SEM, surface potential measurement.