Effects of Electron-Beam/Gas Interactions on X-Ray Microanalysis in the Variable Pressure SEM

摘要

The objective of this investigation is to evaluate the effects induced by the electron-beam/gas interaction on x-ray microanalysis in the variable pressure scanning electron microscope. The occurrence of an electron beam skirting effect implies a loss of x-ray spatial resolution. Skirting is first studied by current measurement, the conduction current being a useful parameter for its evaluation. To minimise the skirting effect, the experimental conditions must be in the pressure range 1 to 20 Pa, and a low working distance and a high accelerating voltage should be used. The atmospheric effect, which includes a direct x-ray contribution from the atmosphere, produces an increase in the oxygen signal when the pressure of air inside the chamber increases.