Specific Features of Energy Dispersive X-Ray Electron Probe Microanalysis in the Low Vacuum Mode

Experimental data on the generation and detection of characteristic X-radiation of elements in electron probe microanalysis of dielectric samples in the low vacuum mode without the deposition of conducting coatings are discussed. The main advantage of the considered method of analysis is the stability of the intensity ratio between diagnostic analyte lines in the wide range of currents of the electron probe and gas phase pressure in the chamber in the range 60–130 Pa, sufficient for obtaining undistorted images of the surface of dielectrics. The stability of the intensity ratio ensures obtaining correct data of the quantitative analysis of nonconducting samples without the deposition of conducting coatings. The main features of low-vacuum microanalysis for the range of gas phase pressures used are discussed, which can create additional difficulties in the study. Among such features is a possibility of the manifestation of reflexes of gas-phase elements, significant underestimation of the relative emission intensity from lighter elements in the composition of the studied samples, loss of scanning locality in the analysis of small sites on the sample surface. An example of the correct quantitative elemental analysis of a dielectric surface without the deposition of an electroconductive coating for a number of aluminosilicates is presented.