Radiation Pulse Height Selection Using Clock-Synchronized Thresholds
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Solution Overview
Problem
Conventional radiation measurement devices experience instability in pulse width and delay times due to variations in resistor and capacitor characteristics, leading to count loss and measurement errors.
Innovation Solution
A radiation measurement device incorporating a first and second pulse height detection circuit, a crystal oscillator, and combining circuits to synchronize detection pulses within specific thresholds, ensuring accurate extraction of detection pulses between lower and upper thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a one-shot multivibrator with resistor and capacitor elements is used for pulse height selection, then the circuit can be implemented with conventional components, but the pulse width and delay time become unstable due to element characteristic variations
Solution Approach 1:
The patent replaces the conventional one-shot multivibrator circuit (mechanical/electrical component-based system) with a digital logic circuit system that uses flip-flops, logic gates, and a crystal oscillator. This substitution eliminates the instability caused by resistor and capacitor characteristic variations, as digital logic circuits provide stable and precise timing control through their inherent binary state characteristics and clock synchronization mechanisms.
Solution Approach 2:
The patent changes the fundamental operating parameters from analog component characteristics (resistor values, capacitor values) to digital logic states (0 and 1) and clock cycle counts. By using a crystal oscillator to generate a stable clock signal and counting its cycles with flip-flops, the system achieves stable pulse width and delay time that are independent of component tolerances and environmental variations.
2Device complexity
If conventional pulse height selection circuits are used, then the device structure remains simple, but count loss and measurement errors occur due to unstable pulse extraction
Solution Approach 1:
The patent replaces the unstable analog pulse height selection circuit with a digital logic-based system that uses flip-flops, logic gates, and clock synchronization. This digital approach ensures stable and accurate extraction of pulses within the specified height range, eliminating count loss and measurement errors while maintaining reasonable device complexity through the use of standard digital logic components.
Solution Approach 2:
The patent implements feedback mechanisms through the clock-synchronized digital logic circuitry. The crystal oscillator provides a stable reference clock that synchronizes the operation of flip-flops and logic gates, creating a feedback-controlled system that consistently and accurately identifies pulses within the threshold range. This feedback ensures that only valid pulses are counted, improving measurement precision.
3Ease of manufacture
If element characteristics vary in conventional circuits, then manufacturing tolerances are accommodated, but pulse width and delay time become unstable leading to extraction errors
Solution Approach 1:
The patent replaces the component-characteristic-dependent analog circuit with a digital logic system that is inherently insensitive to component variations. The crystal oscillator provides a stable frequency reference, and the flip-flops and logic gates operate based on digital logic levels rather than analog component characteristics. This substitution ensures that pulse extraction accuracy is maintained regardless of manufacturing tolerances in individual components.
Solution Approach 2:
The patent transitions from relying on analog component parameters (resistor values, capacitor values) to using digital logic parameters (logic levels, clock frequency, flip-flop states). This parameter change makes the system immune to the variations inherent in component manufacturing, as digital logic components have well-defined switching thresholds and the crystal oscillator provides a precise frequency reference that is independent of component tolerances.
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
Enables stable and accurate measurement of radiation intensity by ensuring only pulses within the defined range are extracted, reducing errors and count loss.
Implementation Method 1
a crystal oscillator for generating a clock pulse with a certain cycle
Data Source
AI summary
First and second pulse height detection circuits output pulse height detection signals which rise when a detection pulse obtained from a radiation detector becomes greater than a lower threshold Lsh or an upper threshold Hsh, and fall when the detection pulse is smaller than the lower threshold Lsh or the upper threshold Hsh. Next, first and second rising and falling detection circuits detect rising and falling edges of the pulse height detection signals from the first and second pulse height detection circuits in synchronization with a clock pulse from a crystal oscillator, and a combining circuit outputs a signal corresponding to the detection pulse that is within a range between the lower threshold Lsh and the upper threshold Hsh by combining both outputs from the first and second rising and falling detection circuits, in synchronization with the clock pulse.