X-ray surface analysis and measurement apparatus

摘要

This disclosure presents systems for total reflection x-ray fluorescence measurements that have x-ray flux and x-ray flux density several orders of magnitude greater than existing x-ray technologies. These may therefore useful for applications such as trace element detection and/or for total-reflection fluorescence analysis. The higher brightness is achieved in part by using designs for x-ray targets that comprise a number of microstructures of one or more selected x-ray generating materials fabricated in close thermal contact with a substrate having high thermal conductivity. This allows for bombardment of the targets with higher electron density or higher energy electrons, which leads to greater x-ray brightness and therefore greater x-ray flux. The high brightness/high flux source may then be coupled to an x-ray reflecting optical system, which can focus the high flux x-rays to a spots that can be as small as one micron, leading to high flux density.

主权项

1. An x-ray system for analyzing a sample, comprising:
at least one x-ray source comprising: a vacuum chamber; a window transparent to x-rays attached to the wall of the vacuum chamber; and, within the vacuum chamber: at least one electron beam emitter, and an anode target comprising: a substrate comprising a first selected material, and
a planar first surface, from which thickness is measured in a direction perpendicular to the first planar surface, and two orthogonal lateral dimensions are measured parallel to the first planar surface; and a plurality of discrete structures embedded into the first planar surface of the substrate such that each of the plurality of discrete structures is in thermal contact with the substrate, the plurality of discrete structures comprising:
one or more materials selected for its x-ray generation properties; in which at least two of the plurality of discrete structures are arranged on a predetermined axis; in which the predetermined axis is parallel to the first planar surface of the substrate; in which the predetermined axis passes through the first window; in which each of the discrete structures has a thickness of less than 20 microns, and
in which each of the plurality of discrete structures has a lateral dimension in the direction of the predetermined axis of less than 50 microns; and a means of directing electrons emitted by the at least one electron beam emitter onto the at least two arranged discrete structures such that x-rays are generated from each of the at least two arranged discrete structures; in which at least a portion of the generated x-rays propagating on the predetermined axis from each of the two arranged discrete structures is transmitted through the window; and additionally comprising: an x-ray optical system
having an optical axis aligned relative to said predetermined axis, said optical system positioned to collect diverging accumulated x-rays from said at least two arranged discrete structures in the x-ray source and to condition and create an x-ray beam with predetermined properties; said optical system additionally comprising a central beam stop positioned to block x-rays propagating parallel to the optical axis; a means to direct the x-ray beam to be incident onto an area of the surface of a sample at a grazing angle less than the critical angle with the surface; at least one detector positioned to detect the intensity of the x-rays emerging from the sample and generate electrical signals; and a signal processor to analyze the electrical signals to obtain information about at least one of:
composition, concentration, quantity, and film thickness.