Photon Counting Detector Pixel Modulation for Wider Flux Range
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Solution Overview
Problem
Radiographic scanning systems face challenges in accurately recording photon counts across a wide dynamic range of flux rates, leading to inaccuracies due to deadtime losses, pulse pileup, and statistical errors.
Innovation Solution
The system employs a combination of large and small pixels in the photon counting detector, along with adjustable slit apertures and photon absorbers, to modulate the photon flux and optimize pixel detection capabilities across varying attenuation paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single pixel size is used in the photon counting detector, then the detector structure is simple, but it cannot accurately handle a wide dynamic range of photon flux rates
Solution Approach 1:
The patent applies local quality by implementing pixels of different sizes (first pixels with first size, second pixels with second size) in different regions of the detector. Larger pixels are positioned in regions receiving higher photon flux while smaller pixels are positioned in regions receiving lower flux, allowing each pixel to operate within its optimal detection range and thereby extending the overall dynamic range of the detector.
2Productivity
If high photon flux is used to improve signal strength, then measurement speed increases, but deadtime losses and pulse pileup increase
Solution Approach 1:
The patent changes the physical parameter of pixel size to optimize detection performance. By providing pixels with different sizes, the system can handle a broader range of photon flux rates without suffering from deadtime losses or pulse pileup, as each pixel size is optimized for specific flux conditions.
3Measurement precision
If low photon flux is used to reduce deadtime losses, then measurement accuracy improves, but signal strength and measurement speed decrease
Solution Approach 1:
The patent applies local quality by implementing pixels of different sizes (first pixels with first size, second pixels with second size) in different regions of the detector. Larger pixels are positioned in regions receiving higher photon flux while smaller pixels are positioned in regions receiving lower flux, allowing each pixel to operate within its optimal detection range and thereby extending the overall dynamic range of the detector.
4Measurement precision
If uniform pixel density is used across the detector, then manufacturing is simplified, but detection accuracy varies in central versus outer regions
Solution Approach 1:
The patent implements non-uniform pixel density where the pixel density of the first pixels is greater in a central third of the photon counting detector than in outer thirds. This local optimization ensures that regions with different attenuation characteristics receive appropriate pixel density for accurate measurement.
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 the system to accurately handle a wider range of photon fluxes, reducing errors and improving image quality and measurement accuracy in both thick and thin target regions.
Implementation Method 1
a photon absorber positioned adjacent an outer portion of the slit aperture to absorb a portion of the photons emitted from the photon source
Data Source
AI summary
Systems and methods for improving radiographic scanning. In an example, the technology relates to a system for performing radiographic scanning. The system includes a photon source configured to emit photons. The system also includes a photon counting detector for detecting photons emitted from the photon source after passing through a target. The photon counting detector comprising first pixels having a first size and second pixels having a second size, and the first size is greater than the second size.