Radiation Image Sensor with Thresholded Energy Integration
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Solution Overview
Problem
Photon counting radiation detectors face issues with noise due to non-uniform incident timing of radiation, leading to inaccuracies in particle counting, while charge accumulation detectors integrate noise along with true signal components, including dark current and other noise sources.
Innovation Solution
A radiation detector with a charge generation part, preamplification, signal conversion, energy discrimination, and energy integration parts, which removes noise from digital signals before integration, allowing for simpler circuit configurations and reduced size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If photon counting method is used to count incident particles, then noise problems are reduced, but measurement precision deteriorates due to non-uniform incident timing causing counting errors
Solution Approach 1:
The patent introduces an intermediary integration process between charge generation and final measurement. Instead of directly counting particles, the charge from multiple incident particles is integrated over time to produce an integrated charge signal. This intermediary signal represents the total energy deposited and can be measured with high precision, resolving the contradiction between noise reduction and measurement accuracy.
2Measurement precision
If charge accumulation method is used to integrate signal components, then measurement precision is improved, but noise is integrated along with true signals including dark current
Solution Approach 1:
The patent applies preliminary discrimination before integration by comparing each detected charge signal against a predetermined threshold. Only signals exceeding this threshold (indicating genuine radiation events) are integrated, while signals below the threshold (dark current and noise) are rejected. This preliminary action prevents noise integration while maintaining precise measurement of true radiation signals.
3Device complexity
If simple addition operation is used for energy integration, then device complexity is reduced, but noise removal capability is compromised
Solution Approach 1:
The patent implements threshold comparison as a preliminary action before the simple addition operation. Each charge signal is compared against a threshold value, and only signals exceeding the threshold are passed to the integrator. This allows the use of simple addition arithmetic while effectively removing noise, as the threshold filtering occurs beforehand.
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
The detector effectively reduces noise, maintains accurate energy integration, and avoids pile-up errors, enhancing the linearity of radiation detection without losing information.
Implementation Method 1
a charge generation part configured to generate charge corresponding to energy of an incident radiation
Data Source
AI summary
A radiation detector includes a charge generation part configured to generate charge corresponding to energy of an incident radiation, a preamplification part configured to output an analog signal corresponding to the charge, a signal conversion part configured to receive the analog signal and output a digital signal being the analog signal that has been discretized, an energy discrimination part configured to compare the digital signal to a threshold value and output components of the digital signal exceeding the threshold value, and an energy integration part configured to obtain an energy integrated value defined as a summation of the components exceeding the threshold value obtained each time the radiation enters.