XRF Element Localization via Collimated Inspection Volumes
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Solution Overview
Problem
Current XRF analysis methods struggle to accurately localize elements of interest, such as lead, in heterogeneous samples like consumer goods with multiple layers, especially in thin, low-density materials, and cannot distinguish between coating and bulk lead effectively, limiting their applicability to various elements and sample matrices.
Innovation Solution
The method involves irradiating the sample with exciting radiation to create two overlapping inspection volumes, one extending to both the coating layer and bulk, and another only to the bulk, by varying the collimation or blocking of x-rays, allowing for the comparison of characteristic x-ray intensities to determine the element's location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the intensity ratio method using two characteristic x-ray lines is employed to determine element location, then satisfactory results are obtained for certain applications, but the method cannot be successfully employed for a broader range of elements and sample matrices including thin low-density materials
Solution Approach 1:
The inspection volume is segmented into multiple distinct volumes (first inspection volume extending to coating layer and bulk, second inspection volume extending only to bulk) by using different collimator settings. This segmentation allows separate measurement of element concentrations in different spatial regions, enabling reliable localization across diverse sample types including thin low-density materials where the intensity ratio method fails
Solution Approach 2:
The invention transitions from a one-dimensional intensity ratio measurement to a multi-dimensional approach by measuring x-ray intensities from multiple spatially distinct inspection volumes. This dimensional expansion in the spatial domain provides additional information for determining element location, achieving versatility across different elements and matrices while maintaining localization accuracy
2Measurement precision
If a single inspection volume is used for XRF analysis, then the measurement process is simple, but the ability to distinguish between coating and bulk element location is lost
Solution Approach 1:
The collimator is configured to dynamically change inspection volumes by adjusting its position or orientation, allowing the system to switch between different inspection volume configurations (first volume including coating and bulk, second volume including only bulk). This dynamic reconfiguration enables precise element location determination without requiring permanently fixed complex multi-volume hardware
Solution Approach 2:
The system uses the same XRF measurement apparatus and detector for all inspection volumes, with the collimator serving multiple functions by reconfiguring to define different volumes. This self-service approach allows one component to perform multiple measurement functions, reducing overall device complexity while maintaining 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 enables reliable localization of elements within samples, distinguishing between coating and bulk lead, and can be applied to a broader range of elements and sample types, improving the accuracy of lead concentration determination based on its location.
Implementation Method 1
In XRF analysis, a radioisotope source or x-ray tube generates a beam of exciting radiation which is directed onto a sample. Elements in the sample responsively emit fluorescent x-rays of characteristic energies.
Implementation Method 2
The emitted x-rays are sensed by a detector, which produces signals representative of the energies of the received x-rays.
Implementation Method 3
The inspection volumes may be controllably changed by varying the collimation of the exciting and/or fluoresced x-rays (e.g., by moving one or more collimator structures)
Data Source
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Figure 3A~3B
AI summary
An apparatus and method are disclosed for localizing an element of interest in a sample by comparing XRF spectra acquired from at least two distinct but overlapping inspection volumes. The inspection volumes are varied by changing the geometry of the exciting x-ray and/or fluoresced x-ray beam(s), which may be accomplished by repositioning multi-apertured collimators. Comparison of the XRF spectra acquired from different inspection volumes provides an indication as to whether the element of interest (e.g., lead) is present in a coating layer, in the underlying bulk material, or in both.