Monolithic Side-by-Side X-Ray Detector for Material Discrimination
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Solution Overview
Problem
Conventional dual-energy x-ray detectors face challenges such as difficulty in independent control of high-energy detector arrays, attenuation of high-energy photons by low-energy detectors, mechanical alignment issues, and limited signal-to-noise ratio due to parasitic impedances and complex assembly processes, which affect image quality and material discrimination.
Innovation Solution
A novel dual-energy or multi-energy range x-ray detector with side-by-side monolithic integration of photoelements and signal processing circuitry on a single semiconductor substrate, allowing for improved alignment, reduced parasitic impedances, and scalable multi-energy range capabilities, including time-delayed integration and selective radiation shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate detector arrays are used for low-energy and high-energy x-ray detection, then material discrimination capability is improved, but mechanical alignment difficulty increases
Solution Approach 1:
The patent combines separate low-energy and high-energy detector arrays into a single integrated detector array. This merging eliminates the need for mechanical alignment between separate arrays while maintaining the ability to detect different energy ranges through electronic energy discrimination, thus resolving the contradiction between material discrimination capability and mechanical alignment difficulty.
Solution Approach 2:
The integrated detector array serves multiple functions by detecting both low-energy and high-energy x-rays simultaneously using a single structure. This multi-functionality approach allows the same physical array to perform both energy ranges detection without requiring separate aligned arrays, thereby solving the alignment problem while preserving material discrimination capability.
2Measurement precision
If separate detector arrays are used for low-energy and high-energy x-ray detection, then energy-specific detection is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple detector arrays into one integrated array that can detect both low-energy and high-energy x-rays. This consolidation reduces device complexity by eliminating redundant structures while maintaining energy-specific detection capabilities through electronic discrimination methods.
Solution Approach 2:
The single integrated detector array is designed to perform multiple detection functions across different energy ranges. This universal detector replaces what would otherwise require multiple specialized arrays, thereby reducing overall device complexity while preserving the ability to perform energy-specific detection and material discrimination.
3Measurement precision
If separate detector arrays with stacked configuration are used, then low-energy and high-energy detection are improved, but parasitic noise increases
Solution Approach 1:
The patent combines detection functions into a single integrated array rather than using stacked separate arrays. This merging eliminates the parasitic noise that arises from the stacked configuration where one array is positioned in front of the other, as the integrated design allows for optimized signal collection without intermediate structures that generate noise.
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 configuration enhances image quality, reduces manufacturing and assembly costs, and improves signal-to-noise ratio, enabling better material discrimination and scalability beyond dual-energy ranges.
Implementation Method 1
A planar and monolithic semiconductor substrate containing a plurality of photoelements... each array of elements being selectively responsive to a specific x-ray energy range or spectrum
Implementation Method 2
an x-ray shield sufficiently attenuating x-rays from directly impinging on said MOS devices
Data Source
AI summary
A dual or multi-energy range x-ray image sensor is implemented as side-by-side pixel arrays on a planar and monolithic semiconductor substrate as part of an x-ray object detector. Each pixel array in this side-by-side monolithic arrangement is designed to be responsive to a particular x-ray energy range or spectrum (i.e. a high-energy (HE) range or a low-energy (LE) range) to provide high object sensitivity and material discrimination capabilities. The side-by-side monolithic construction of pixel arrays improves alignment and spacing precision for improved image alignment among different arrays specialized in detecting different energy levels and signatures. Furthermore, integrated signal processing circuitry, placed on a radiation-shielded periphery of the pixel arrays, enables improved detection performance with enhanced noise reduction and/or sensitivity. This novel configuration is scalable by increasing the number of side-by-side and monolithically-placed pixel arrays, each of which is specialized in detecting a specific energy range from a scanned object.