Characteristics, performance, and quantitative analytical capability of an energy-dispersive spectrometer on an electron microprobe using low operating voltages

An investigation was made of the analytical capability of a Si (Li) x-ray detector for energy-dispersive techniques in the 1- to 10-keV photon energy range with multiple single channel analyzers using the electron microprobe beam as the excitation source at operating voltages of 10 to 20 kV. This system can provide rapid, accurate, simultaneous, quantitative elemental microanalysis of major constituents in complex solids for all elements heavier than Si where spectral interferences are absent and reference standards are used. Calculated theoretical detection limits are about 0.2 wt %. A relative precision of about 1 to 5% is routine for a 10- or 20-sec counting period for elements in concentrations above about 5 wt %. Data for K, L, and M x-ray spectra of representative elements ranging in energy from 1.25 to 8.64 keV are presented for operating voltages of 10,15, and 20 kV and beam currents of 1 to 10 nA.