Sawtooth Threshold Voltage Signal Acquisition for Scintillation Crystals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for acquiring energy and time information from scintillation signals are either expensive, prone to noise, or sacrifice precision, particularly in time-based signal acquisition technologies like Time-over-Threshold (ToT), which have poor energy resolution and cannot estimate decay time.
Innovation Solution
A time-based signal acquisition apparatus and method using sawtooth-shaped threshold voltage, which generates a voltage that increases when below the scintillation signal and decreases to an initial value when above, allowing for precise energy and time information acquisition through digital pulse trains without requiring expensive equipment or sacrificing precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If Time-over-Threshold (ToT) method is used for time-based signal acquisition, then the measurement cost is reduced and device complexity is simplified, but energy resolution deteriorates and measurement precision worsens
Solution Approach 1:
The patent applies dynamics by making the threshold voltage time-dependent rather than fixed. The threshold voltage dynamically changes over time following an exponential decay profile, allowing the measurement system to adapt its sensitivity throughout the signal duration. This dynamic threshold enables precise energy measurement across varying signal amplitudes while maintaining simple ToT-based timing measurement, thus improving energy resolution without increasing device complexity
Solution Approach 2:
The patent changes the threshold voltage parameter from a constant value to a time-varying parameter that decays exponentially. This parameter transformation allows the measurement system to capture energy information more effectively by adjusting the threshold level throughout the signal pulse, thereby improving energy resolution and measurement precision while maintaining the simplicity of the ToT method
2Measurement precision
If high sampling rate ADC (several GHz) is used to precisely measure time information, then measurement precision is improved, but cost increases and heat radiation worsens
Solution Approach 1:
The patent replaces the high-speed ADC-based measurement system with a time-based measurement approach using simple voltage threshold comparison. Instead of using expensive high-frequency analog-to-digital conversion hardware that generates significant heat, the system uses a low-frequency comparator to generate digital pulses based on threshold crossings. This substitution achieves precise time measurement through digital pulse train analysis rather than high-speed analog sampling, dramatically reducing heat radiation and cost while maintaining measurement precision
3Measurement precision
If QDC method is used for energy measurement, then energy measurement precision is improved, but additional TDC is required for time measurement increasing device complexity
Solution Approach 1:
The patent merges energy measurement and time measurement functions into a single integrated process. By using the same threshold voltage comparison circuit to generate digital pulses, the system simultaneously obtains both energy information (from the pulse train characteristics) and time information (from pulse timing). This unified approach eliminates the need for separate QDC and TDC modules, reducing device complexity while maintaining measurement precision for both energy and time parameters
Data Source
AI summary
Disclosed herein are a time-based signal acquisition apparatus and method using sawtooth-shaped threshold voltage. The signal acquisition apparatus for acquiring the information of a scintillation signal includes a sawtooth-shaped voltage generation unit and a signal comparison unit. The sawtooth-shaped voltage generation unit generates a sawtooth-shaped threshold voltage which increases when the threshold voltage is smaller than a voltage value of the scintillation signal and which decreases to an initial value when the threshold voltage is larger than the voltage value of the scintillation signal. The signal comparison unit receives the scintillation signal, compares the voltage value of the scintillation signal with the threshold voltage, and generates a digital pulse train.