X-ray Signal Processing Device with Dynamic Preamplifier Reset Control
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Solution Overview
Problem
Conventional X-ray detection signal processing devices face challenges in achieving a high signal-to-noise (SN) ratio and high energy resolution, especially when the frequency of X-ray incidence increases or cosmic rays are detected, due to signal saturation and noise generation from preamplifier characteristics.
Innovation Solution
An X-ray detection signal processing device that includes a continuous reset type preamplifier with a CR circuit, a clock oscillator, a high-speed AD converter, a comparator, and a control section to manage signal processing by stopping high-speed AD conversion when the signal exceeds a predetermined upper limit and delaying restart, thereby maintaining output quality and preventing energy resolution degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pulse reset type preamplifier is used to maintain signal levels within unsaturated range, then signal saturation is prevented, but the SN ratio deteriorates and high counting rate cannot be addressed
Solution Approach 1:
The patent changes the operating parameters of the preamplifier by switching between pulse reset mode (for saturation prevention) and continuous reset mode (for high SN ratio). This parameter change allows the system to optimize for different operational conditions, achieving both saturation prevention and high measurement precision simultaneously.
Solution Approach 2:
The patent introduces dynamic control of the preamplifier reset mechanism. The control section dynamically switches between pulse reset and continuous reset operations based on signal conditions, enabling the system to adapt to varying X-ray counting rates and maintain optimal performance across different operational states.
2Measurement precision
If a continuous reset type preamplifier is used to improve SN ratio, then SN ratio is improved, but signal saturation occurs when X-ray frequency increases
Solution Approach 1:
The control section dynamically adjusts the preamplifier's reset behavior based on real-time signal conditions. When X-ray frequency increases and saturation risk arises, the system switches to pulse reset mode, maintaining the ability to handle high counting rates while preventing signal saturation.
Solution Approach 2:
The patent implements feedback control where the control section monitors the preamplifier output signal and adjusts the reset mechanism accordingly. This feedback loop ensures that the system automatically responds to changing signal conditions, preventing saturation while maintaining high SN ratio.
3Productivity
If high-speed AD conversion is continuously performed to capture all signals, then signal capture completeness is improved, but energy resolution deteriorates due to noise from preamplifier characteristics
Solution Approach 1:
The patent employs periodic high-speed AD conversion triggered by signal arrival detection rather than continuous conversion. The control section activates AD conversion only when a signal arrives at the preamplifier, reducing noise interference while ensuring complete signal capture. This periodic operation maintains productivity while improving energy resolution.
Solution Approach 2:
The control section performs preliminary detection of signal arrival before initiating high-speed AD conversion. This preliminary action allows the system to prepare for conversion only when necessary, avoiding unnecessary conversion operations that would introduce noise and degrade energy resolution while maintaining complete signal capture.
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 solution enhances the SN ratio, supports high counting rates, and ensures accurate pulse height analysis at high energy resolution even under increased X-ray frequencies or cosmic ray incidence, by effectively handling signal saturation and noise.
Implementation Method 1
a preamplifier configured to amplify the signal from the X-ray detector, and attenuate the signal according to a time constant of a CR circuit
Implementation Method 2
a high-speed AD converter configured to operate based on oscillation of the clock oscillator and subject a signal from the preamplifier to high-speed AD conversion
Implementation Method 3
a comparator configured to output a High signal when a level of the signal from the preamplifier does not exceed a predetermined upper limit value, and output a Low signal when the level of the signal from the preamplifier exceeds the predetermined upper limit value
Implementation Method 4
a signal from an X-ray detector is inputted
Data Source
AI summary
An X-ray detection signal processing device (10) and the like according to the present invention includes: a comparator (17) configured to output a High signal when a level of a signal from a continuous reset type preamplifier (13) having an CR circuit (13a) does not exceed a predetermined upper limit value, and output a Low signal when the level of the signal from the preamplifier (13) exceeds the predetermined upper limit value; and a control section (18) configured to delay shift of the signal of the comparator (17) from Low to High by a predetermined time, to perform output to a clock oscillator (15), stop oscillation by outputting a Low signal to the clock oscillator (15), and thus stop high-speed AD conversion by a high-speed AD converter (14) and maintain an output value.