Quantitative x-ray microfluorescence analysis of small areas and individual particles

Abstract

During the past few years, rapid progress has been made in the development of collimated x-ray sources which permit energy-dispersive x-ray analysis of small areas with dimensions below 100 μm. An x-ray microfluorescence spectrometer developed at NIST employs a commercial low-power (50 WATTS) x-ray tube providing a small focused x-ray beam (0.25 × 0.25 mm). The x-ray beam size was further reduced with a Mo collimator tipped with a Pt foil having a 70μm hole in the center. The x-ray beam profile was measured by step scanning across Cu wires 50 μm in diameter in both X and Y directions. The cross section of the beam was approximated by a Gaussian function with a FWHM of 43 μm. A schematic diagram of the spectrometer which is capable of operation in vacuum is shown in Figure 1.Other features include a close coupled source-sample-detector for optimum count rate, a motorized x-y stage, and a color video camera for continuous viewing of the sample at normal incidence.