X-Ray Absorption Spectrometer Using Low-Bragg Crystal Analysis
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Solution Overview
Problem
Laboratory x-ray absorption spectroscopy systems face limitations in brightness, spectral resolution, and throughput due to low x-ray flux density and the need for multiple crystal analyzers operating at high Bragg angles, leading to long acquisition times and poor energy resolution.
Innovation Solution
A method and system utilizing a laboratory x-ray source with an optical train that focuses x-rays over an energy bandwidth greater than 10 eV onto an object, incorporating capillary x-ray optics and novel x-ray targets with microstructures for high thermal conductivity, allowing higher electron density and energy, and using crystal analyzers at low Bragg angles for high throughput and spatial resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional laboratory x-ray sources are used, then the system is compact and accessible, but the x-ray flux density is low resulting in long acquisition times and poor spectral resolution
Solution Approach 1:
The patent changes the operating parameters of the x-ray source by using higher electron beam energies (up to 50 keV or higher) and optimizing the target material composition to increase x-ray flux. It also changes the optical configuration from conventional to one using capillary optics with specific geometries that improve focusing and increase flux density at the sample, thereby achieving better spectral resolution without proportionally increasing acquisition time
Solution Approach 2:
The system employs dynamic optimization by adjusting the electron beam parameters (current, energy, spot size) in real-time based on the measurement requirements. The optical train is also dynamically adjustable to optimize the balance between flux density and energy bandwidth during different phases of the measurement process
2Measurement precision
If crystal analyzers operate at high Bragg angles to achieve energy resolution, then spectral resolution improves, but throughput decreases due to lower diffraction efficiency
Solution Approach 1:
The patent fundamentally changes the Bragg angle parameter from conventional high angles (60-80 degrees) to low angles (10-30 degrees). This parameter change increases the diffraction efficiency and throughput while maintaining adequate energy resolution through compensating optimizations in crystal orientation and detector geometry
Solution Approach 2:
The system compensates for the reduced angular dispersion at low Bragg angles by introducing additional spatial dimensions in the detection geometry. The detector is positioned and oriented in a specific three-dimensional configuration that captures the diffracted x-rays effectively, maintaining energy resolution through spatial separation rather than angular separation alone
3Adaptability or versatility
If multiple crystal analyzers are used to cover different energy ranges, then energy coverage improves, but device complexity increases
Solution Approach 1:
The patent employs a universal low-Bragg-angle crystal analyzer configuration that can effectively analyze a broad energy range (from a few keV to tens of keV) without requiring multiple specialized analyzers. The capillary optic system is also designed to be multi-functional, capable of focusing x-rays across different energy bands through adjustable parameters, thereby reducing system complexity while maintaining versatility
Solution Approach 2:
The system uses dynamic reconfiguration capabilities where a single analyzer-crystal-detector assembly can be adjusted in orientation and position to optimize measurements across different energy ranges. This dynamic adaptability replaces the need for multiple fixed analyzers, simplifying the overall system architecture
4Illumination intensity
If electron beam energy is increased to improve x-ray brightness, then x-ray flux increases, but thermal damage to the target material occurs
Solution Approach 1:
The patent uses target materials with locally optimized properties, including layered structures where the x-ray generating layer is thin and designed for optimal x-ray production, while underlying layers provide thermal conduction to dissipate heat. The electron beam is also focused to a specific spot size that optimizes the balance between brightness and heat distribution
Solution Approach 2:
The target is constructed as a composite structure combining materials with complementary properties: high-Z materials for efficient x-ray generation, high thermal conductivity materials for heat dissipation, and structurally stable materials to withstand thermal stress. This composite approach enables operation at higher electron beam energies without target damage
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves high x-ray flux and spatial resolution, enabling faster and more accurate x-ray absorption spectroscopy measurements with improved spectral resolution and compactness, overcoming the limitations of prior laboratory systems.
Implementation Method 1
an optical train which focuses x-rays over an energy bandwidth greater than 10 eV emerging from the x-ray source on or near an object
Implementation Method 2
capillary x-ray optics
Implementation Method 3
using crystal analyzers at low Bragg angles for high throughput and spatial resolution
Implementation Method 4
A spectrum of x-rays is produced with x-ray energies up to the original electron energy (in this example, about 50 KeV) which includes characteristic x-rays and continuum, often referred to as Bremsstrahlung radiation
Implementation Method 5
laboratory sources of x-rays are created by bombarding an anode target having a selected x-ray generating material with electrons accelerated through a potential
Data Source
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AI summary
A method for performing x-ray absorption spectroscopy and an x-ray absorption spectrometer system to be used with a compact laboratory x-ray source to measure x-ray absorption of the element of interest in an object with both high spatial and high spectral resolution. The spectrometer system comprises a compact high brightness laboratory x-ray source, an optical train to focus the x-rays through an object to be examined, and a spectrometer comprising a single crystal analyzer (and, in some embodiments, also a mosaic crystal) to disperse the transmitted beam onto a spatially resolving x-ray detector. The high brightness/high flux x-ray source may have a take-off angle between 0 and 105 mrad. and be coupled to an optical train that collects and focuses the high flux x-rays to spots less than 500 micrometers, leading to high flux density. The coatings of the optical train may also act as a "low-pass" filter, allowing a predetermined bandwidth of x-rays to be observed at one time while excluding the higher harmonics.