Atmospheric electron X-ray spectrometer development

Abstract

The development of a portable surface elemental analysis tool based on the excitation of characteristic X-rays at ambient pressure with an electron beam is described. This instrument relies on the use of a thin electron transmissive membrane to isolate the vacuum of the electron source from the ambient atmosphere. The major advantages offered by this instrument include rapid spectrum acquisition, nondestructive evaluation of elemental composition, and high spatial resolution in comparison to similar portable instruments. The instrument proof-of-principle has been demonstrated by obtaining energy dispersive X-ray spectra from metal and mineral samples. SEM experiments have been carried out to determine beam spot size and quantitative analysis limits. Modeling has been performed to study performance limits and to understand the influence of membrane and atmosphere interactions on the focused electron beam.