US 9,594,036 B2Granted

X-ray surface analysis and measurement apparatus

AssigneeSigray, Inc.

InventorsWenbing Yun, Sylvia Jia Yun Lewis, Janos Kirz

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Abstract

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.

Claims31

Dependent claims

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.

27 more elements

An x-ray measurement system, comprising:

an 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 at least two arranged discrete structures is transmitted through the window;
and additionally comprising:
an optical train having an optical axis to collect diverging x-rays generated by said at least two of the plurality of discrete structures in the anode target, and that produces an x-ray beam with predetermined beam properties;
said optical train additionally comprising a central beam stop positioned to block x-rays propagating parallel to said optical axis;
a mount to hold an object to be investigated, positioned such that the x-ray beam will be incident onto an area of the surface of the object at a grazing angle less than the critical angle with the surface;
a detector to measure x-rays emerging from the object when x-rays are incident on the object.

24 more elements

An x-ray measurement system, comprising:

an x-ray source comprising:
a vacuum chamber;
a first window transparent to x-rays attached to the wall of the vacuum chamber;
and,
within the vacuum chamber, one or more electron emitters;
and
a plurality of x-ray targets;
with each target comprising a material selected for its x-ray generating properties, and in which at least one dimension of said material is less than 20 microns;
and
in which said one or more electron emitters and said plurality of x-ray targets are aligned such that bombardment of electrons on said x-ray targets produces x-ray sub-sources such that said sub-sources are aligned along an axis that passes through the first window;
and
at least one x-ray imaging optical element, said x-ray imaging optical element positioned such that x-rays generated by one of said x-ray sub-sources are collected by said x-ray imaging optical element and focused onto a position corresponding to one of the other x-ray sub-sources;
said system additionally comprising:
an optical train comprising:
at least one optical element with an optical axis aligned with said axis such that the at least one optical element collects diverging x-rays generated by said sub-sources and that produces an x-ray beam with predetermined beam properties;
a central beam stop positioned to block x-rays propagating parallel to said optical axis;
a mount to hold an object to be investigated positioned such that the x-ray beam will be incident onto an area of the surface of the object at a grazing angle less than the critical angle with the surface;
and
a detector to measure x-rays emerging from the object when x-rays are incident on the object.

16 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/634,834Filed 1 Mar 2015 · us provisional application
Priority: 28 Feb 2014
Published: US 2015/0247811 A13 Sep 2015
Granted: 14 Mar 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification16 codes

G01N 23/223
By measuring secondary emission from the material: by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence
G01B 15/02
Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma…
G01N 23/085
The radiation being X-rays: x-ray absorption fine structure [XAFS], e.g. extended XAFS [EXAFS]
G01N 23/2076
Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions: for…

Family

Application61/946,475Us provisional application · filed 28 Feb 2014
Application61/946,527Us provisional application · filed 28 Feb 2014
Application62/008,856Us provisional application · filed 6 Jun 2014
Application62/086,132Us provisional application · filed 1 Dec 2014
Application62/117,062Us provisional application · filed 17 Feb 2015
US 2015/0247811 A1Pre-grant publication · published 3 Sep 2015
US 9,594,036 B2This patent

From the US filing history. Foreign family members aren’t listed.