Switchable-Capacitor Particle Detection for Wide Energy Range
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Solution Overview
Problem
Existing radiation sensors are limited to a specific energy range, either providing high energy resolution at the cost of low energy resolution or vice versa, necessitating a system that can measure both high and low energy sources without sacrificing resolution.
Innovation Solution
A detection system utilizing an extended amplitude range chip with switchable capacitors that dynamically adjust to accommodate the deposited charge, allowing measurements from ~500 keV to 3 GeV with 30% energy resolution, using a charge-sensitive amplifier and switching capacitors to share charge across multiple capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large capacitance capacitor is used in the detector, then the top range in energy is improved, but the energy resolution for low energy particles deteriorates
Solution Approach 1:
The patent implements a dynamic capacitor switching system where the capacitance value is adjusted in real-time based on the detected particle energy level. The system transitions from a static capacitor configuration to a dynamic one, selecting appropriate capacitance values (e.g., 50pF, 100pF, 200pF, 500pF, 1nF, 2.2nF, 4.7nF, 10nF, 22nF, 47nF, 100nF, 220nF, 470nF, 1uF, 2.2uF, 4.7uF) to match the energy range of incident particles, thereby maintaining optimal energy resolution across the full detection spectrum from low to high energies.
Solution Approach 2:
The system changes the electrical parameter (capacitance) of the detector based on the detected signal characteristics. When low energy particles are detected, smaller capacitance values are selected to maintain voltage signal levels within the optimal range of the charge-sensitive amplifier. When high energy particles are detected, larger capacitance values are switched in to prevent saturation and extend the measurable energy range, thus adapting the detector parameters to the measurement requirements.
2Adaptability or versatility
If a small capacitor is used in the detector, then the energy resolution for low energy particles is improved, but the system saturates at higher energy
Solution Approach 1:
The patent employs a dynamic capacitor selection mechanism that actively monitors the detected signal and switches between different capacitance values. For low energy particles, the system uses smaller capacitors (e.g., 50pF, 100pF) to maintain adequate voltage signals for precise measurement. When high energy particles are detected, the system automatically switches to larger capacitors (e.g., 1nF, 2.2nF, 4.7nF, 10nF, 22nF, 47nF, 100nF, 220nF, 470nF, 1uF, 2.2uF, 4.7uF) to accommodate the higher charge without saturation, thus preventing signal loss at high energies.
Solution Approach 2:
The system dynamically adjusts the capacitance parameter based on the incident particle energy. By changing the capacitor value in response to detected energy levels, the system maintains optimal operating conditions across the entire energy spectrum. This parameter adaptation ensures that the voltage signal remains within the linear response range of the charge-sensitive amplifier regardless of whether low or high energy particles are detected.
3Adaptability or versatility
If the capacitance is increased to detect higher energies, then the top energy range is improved, but the voltage signal decreases
Solution Approach 1:
The patent implements a dynamic capacitance selection system that adjusts the capacitor value based on the detected particle energy. For low energy particles, smaller capacitance values are used to maintain higher voltage signals that are easier to detect and measure with good signal-to-noise ratio. When high energy particles are detected, larger capacitance values are switched in to prevent amplifier saturation, accepting the resulting voltage decrease as necessary to extend the measurable energy range.
Solution Approach 2:
The system changes the capacitance parameter in direct response to the detected energy level. This parameter adjustment creates an inverse relationship management: when capacitance increases to handle higher energies, the system accepts the corresponding voltage decrease as a trade-off. The key innovation is that this parameter change is dynamic and adaptive, allowing the system to optimize for voltage signal strength at low energies while extending energy range at high energies, rather than being constrained by a fixed capacitance value.
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 accurate radiation measurements across a broad energy range, applicable in aerospace, aeronautics, scientific, and medical communities, enhancing protection and measurement capabilities.
Implementation Method 1
a charged particle or high energy photon strikes a detector substrate, often silicon, and liberates electrons in the detector structure
Implementation Method 2
A potential is applied across the detector which sweeps the newly free electrons to a capacitor. The charge on the capacitor is proportional to the energy of the incident particle
Implementation Method 3
using additional switching capacitors to collect the charge deposited in the solid state detector... a series of capacitors that get switched in to accommodate the deposited charge
Data Source
AI summary
An energy detection system and method for measuring an external energy source. A detector is configured to detect an electric charge from the external energy source and produce a current. A charge sensitive amplifier (CSA) is configured to receive the current from the detector and produce a voltage signal. The CSA includes a first switch controlling a circuit path to a first switchable capacitor having a first capacitance and a second switch controlling a circuit path to a second switchable capacitor having a second capacitance greater than the first capacitance. When the electric charge exceeds a first threshold, the first switch closes the circuit path to the first switchable capacitor. When the electric charge exceeds a second threshold, the second switch closes the circuit path to the second switchable capacitor. The second threshold is greater than the first threshold.