Charge Sharing Calibration in X-ray Detectors

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Energy-resolving X-ray imaging systems face challenges in charge sharing, which affects image quality and spectral separation due to the registration of photon events by multiple electrodes, leading to double or multiple counts for a single photon, compromising energy discrimination capability.

Innovation Solution

The proposed solution involves changing pixel sizes and processing data sets from different pixel configurations to assess and compensate for charge sharing impacts, using a combiner to bin signals and form ratios for calibration data, allowing for correction of charge sharing effects in imaging data, thereby improving energy resolution and flux handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If small pixel sizes are used in energy-resolving X-ray detectors, then flux capabilities and spatial resolution are improved, but charge sharing effects worsen and compromise energy resolution

Engineering Contradiction:
Improveflux capabilitiesVSAvoidenergy resolution
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary calibration measurements at multiple pixel sizes before actual imaging to establish charge sharing correction factors. By pre-characterizing the charge sharing behavior at different pixel configurations, the system can compensate for these effects during imaging without sacrificing energy resolution, thus enabling small pixel sizes to be used while maintaining both flux capability and energy resolution.

Inventive Principle:
Principle #10Preliminary action

2Length of moving object

If pixel size is reduced to improve spatial resolution and flux handling, then charge sharing events increase leading to multiple counting of photons

Engineering Contradiction:
Improvepixel sizeVSAvoidevent counting accuracy
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The system uses feedback from calibration measurements taken at multiple pixel sizes to determine charge sharing correction factors. These correction factors are then applied to the actual imaging data to compensate for charge sharing effects. This feedback mechanism enables accurate photon counting even with small pixel sizes by continuously correcting for the increased charge sharing events.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If charge sharing correction is implemented through multi-pixel size calibration, then energy discrimination capability is improved, but system complexity and calibration time increase

Engineering Contradiction:
Improveenergy discrimination capabilityVSAvoidcalibration system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system changes the pixel size parameter during calibration to characterize charge sharing behavior at multiple scales. By systematically varying this single parameter and using the results to compute correction factors, the system achieves improved energy discrimination without requiring complex hardware modifications or overly complicated calibration procedures.

Inventive Principle:
Principle #35Parameter changes

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 high-rate imaging with small pixel sizes, balancing flux capabilities and energy resolution, and provides effective charge sharing compensation, enhancing the fidelity and quality of X-ray images by correcting for charge sharing distortions.

Implementation Method 1

direct conversion photon counting detectors... conversion of X-radiation into detector signals

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

The combiner is configured to combine the signals generated at the detector sub-system in response to X-radiation exposure

Methodology Applied
Scientific EffectSignal summation:

Data Source

PatentEP3737973B1Charge sharing calibration method and system
Publication Date: 2023.07.12 KONINKLIJKE PHILIPS NV
  • EP3737973B1 patent drawingFigure 1
  • EP3737973B1 patent drawingFigure 2
  • EP3737973B1 patent drawingFigure 3

AI summary

A signal processing system (SPS) and related method. The system comprises an input interface (IN) for receiving at least two data sets, comprising a first data set and second data set. The first data set is generated by an X-ray detector sub-system (XDS) at a first pixel size and the second data set generated at a second pixel size different from the first pixel size. An estimator (EST) is configured to compute, based on the two data sets, an estimate of a charge sharing impact.