Iterative X-ray Analysis for Partial Electron Beam Transmission
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Solution Overview
Problem
Existing methods for determining the composition of materials using energy dispersive or wavelength dispersive spectrometry in electron microscopes often provide unsatisfactory results when the object's thickness is such that part of the electron beam is transmitted, as they assume either infinite or zero thickness, leading to erroneous mass-thickness and concentration calculations.
Innovation Solution
A method involving iterative calculations of incidence, atomic number, and absorption correction terms to accurately determine the mass-thickness and concentration of chemical elements in a zone by exposing the object to an electron beam, measuring X-ray radiation intensities, and modifying intermediate values using specific equations and parameters to account for the object's thickness and angle of incidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the object thickness is assumed to be infinite (fully absorbing), then the measurement model is simplified, but the results become erroneous when the actual thickness is such that part of the electron beam is transmitted
Solution Approach 1:
The patent applies dynamics by implementing an iterative calculation process that dynamically adjusts the mass-thickness and concentration values. Instead of using a static assumption (infinite or zero thickness), the method iteratively refines the intermediate values through multiple calculation cycles, incorporating correction terms that account for partial electron beam transmission. This dynamic approach allows the measurement model to adapt to the actual thickness condition, resolving the contradiction between model simplicity and measurement accuracy.
Solution Approach 2:
The patent changes the parameter of object thickness from a fixed assumption (infinite or zero) to a variable that is iteratively determined. By introducing correction terms that depend on the actual mass-thickness and introducing an iterative refinement process, the method transforms the measurement approach from using fixed parameters to using dynamically adjusted parameters, thereby achieving accurate results for objects with partial electron beam transmission.
2Device complexity
If the object thickness is assumed to be zero (fully transparent), then the measurement model is simplified, but the results become erroneous when the actual thickness causes partial electron beam absorption
Solution Approach 1:
The patent applies dynamics by implementing an iterative calculation process that dynamically adjusts the mass-thickness and concentration values. Instead of using a static assumption (infinite or zero thickness), the method iteratively refines the intermediate values through multiple calculation cycles, incorporating correction terms that account for partial electron beam transmission. This dynamic approach allows the measurement model to adapt to the actual thickness condition, resolving the contradiction between model simplicity and measurement accuracy.
Solution Approach 2:
The patent changes the parameter of object thickness from a fixed assumption (infinite or zero) to a variable that is iteratively determined. By introducing correction terms that depend on the actual mass-thickness and introducing an iterative refinement process, the method transforms the measurement approach from using fixed parameters to using dynamically adjusted parameters, thereby achieving accurate results for objects with partial electron beam transmission.
3Measurement precision
If iterative calculations with multiple correction terms are performed, then the measurement precision is improved, but the calculation complexity and time increase
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction terms (such as the k-factor, φ(ρz)-curve, and absorption correction factors) before the actual measurement and analysis. These correction terms are determined in advance based on the electron beam energy, detector geometry, and material properties. During the iterative analysis, these pre-computed correction terms are applied directly, significantly reducing the computational complexity and processing time while maintaining high measurement precision.
4Measurement precision
If iterative calculations with multiple correction terms are performed, then the measurement precision is improved, but the analysis time increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction terms (such as the k-factor, φ(ρz)-curve, and absorption correction factors) before the actual measurement and analysis. These correction terms are determined in advance based on the electron beam energy, detector geometry, and material properties. During the iterative analysis, these pre-computed correction terms are applied directly, significantly reducing the computational complexity and processing time while maintaining high measurement precision.
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
This approach allows for precise determination of mass-thickness and concentration values, overcoming the limitations of previous methods by considering the actual thickness of the object, resulting in more accurate chemical composition analysis.
Implementation Method 1
measuring, for each chemical element identified, a corresponding intensity of an X-ray radiation emergent from the object on account of the exposure step
Implementation Method 2
the thickness of the object is such that part of the electron beam is transmitted by the said object
Data Source
AI summary
A method for studying a zone of an object, the zone exhibiting a mass-thickness and comprising at least one chemical element, the method including a step of exposing a part of the zone of the object to an electron beam, a step of identifying each chemical element present in the said zone by virtue of the exposure step, a step of measuring, for each chemical element identified, a corresponding intensity of an X-ray radiation emergent from the object on account of the said exposure step, a step of determining a value of the said mass-thickness dependent on each measurement step, and a step of determining a value of the concentration of each chemical element identified using the said value of the mass-thickness determined.