X-ray Spectrum Stacking Correction Method
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Solution Overview
Problem
High photon flow in spectrometry systems leads to degradation of energy resolution and detection efficacy due to the stacking phenomenon, where intense photon flows cause interactions to be indistinguishable, resulting in saturation and erroneous signal generation, particularly in baggage inspection applications.
Innovation Solution
A method to estimate and correct the measured spectrum by calculating the stack spectrum using exposure time and dead time data, iteratively refining the corrected spectrum to account for stacking probabilities and temporal deviations between photon interactions, without modifying the processing circuit but rather through energy spectrum processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high photon flow is used in spectrometry systems, then measurement speed and productivity are improved, but energy resolution and detection efficacy deteriorate due to the stacking phenomenon
Solution Approach 1:
The patent applies preliminary action by calculating and subtracting the stack spectrum from the measured spectrum before final analysis. The correction method proactively removes stacking artifacts by estimating the stack spectrum based on measured spectrum, exposure time, and dead time, then performing iterative subtraction to recover the true spectrum before any quantitative analysis is performed.
Solution Approach 2:
The patent converts the harmful stacking effect into a beneficial correction opportunity. By modeling the stack spectrum based on the measured spectrum and system parameters (exposure time, dead time), the method transforms the distortion caused by high photon flow into quantifiable information that can be mathematically removed, allowing recovery of accurate spectral data even from high-rate measurements.
2Quantity of substance
If high incident photon flow is used during baggage inspection, then detection coverage is improved, but the stacking phenomenon causes saturation and degradation of detection efficacy
Solution Approach 1:
The patent replaces mechanical/electronic signal processing solutions with a computational approach. Instead of modifying processing circuits or using complex electronics to handle high photon flows, the invention uses digital signal processing and mathematical modeling to correct stacking effects after detection, substituting hardware complexity with software-based spectral correction algorithms.
3Measurement precision
If traditional correction methods are used, then some stacking effects are reduced, but device complexity or measurement time increases
Solution Approach 1:
The patent applies self-service by using the measured spectrum itself as the basis for generating the correction. The stack spectrum is estimated directly from the measured spectrum combined with exposure time and dead time parameters, eliminating the need for external reference measurements, calibration sources, or additional sensor systems. The data corrects itself using its own information.
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 effectively corrects for the degradation caused by stacking, improving the energy resolution and detection efficacy of spectrometry systems by accurately distinguishing between photon interactions even at high counting rates, as demonstrated by iterative method performance and experimental data.
Implementation Method 1
the incident X photons on the sensor interact with a polarized semiconductor material (CdTe for example), and create a cloud of electronic charges
Data Source
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AI summary
The invention concerns a method for correcting a measured spectrum of X radiation (Spmes) t according to a number of channels Nc, each channel i corresponding to an energy range between Ei and Ei + ?Ei, including: - determining the function dti,,j (k) determining the size of the temporal deviation ?t interval separating two interactions with energy Ei and Ej, the stacking of which leads to a detected energy value Ek, - determining, from said function dti,,j(k), the probability function Pi,,j (k) that an event counted in a channel k corresponds to a stack of two interactions, respectively of energies Ei and Ej, - determining, from said probability function Pi,,j (k), a stack spectrum (Emp), which is the part of the measured spectrum (Spmes), that corresponds only to the stacks alone, - calculating or estimating at least a first corrected spectrum (Spcor), by the difference between the measured spectrum (Spmes) and the stack spectrum (Emp).