Low Voltage Ion Chamber Radiation Detection
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Solution Overview
Problem
Ion chambers used for detecting high-energy radiation face challenges in providing reliable and accurate measurements due to small ion currents, noise sensitivity, and instability from temperature, humidity, and leakage currents, especially under field conditions.
Innovation Solution
Operating ion chambers at low voltages (5V to 20V) with a pulse mode or alternating polarity to minimize noise and leakage current impact, while measuring ion current signals and determining radiation flux based on these conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high voltage is applied to the ion chamber to ensure sufficient ion current, then the ion current magnitude is improved, but the noise and leakage current increase significantly
Solution Approach 1:
The patent applies periodic pulsed voltage instead of continuous voltage to the ion chamber. The voltage is applied in short pulses (e.g., 100 microseconds) at specific intervals, allowing ion collection during the pulse and resetting between pulses. This periodic action maintains sufficient ion current during measurement while minimizing continuous noise and leakage current accumulation, directly resolving the contradiction between measurement accuracy and noise reduction.
Solution Approach 2:
The patent dynamically adjusts the voltage application timing and duration based on measurement requirements. By controlling the pulse width, frequency, and duty cycle, the system optimizes the balance between obtaining sufficient ion current signal and minimizing noise/leakage current effects. This dynamic control allows the ion chamber to operate effectively at lower voltage levels compared to traditional continuous operation.
2Object-affected harmful factors
If low voltage is used to reduce noise and leakage current, then the harmful factors are reduced, but the ion current becomes too weak for accurate measurement
Solution Approach 1:
By concentrating the voltage application into intense short pulses rather than continuous low voltage, the system achieves sufficient ionization during the pulse duration while keeping the average power and continuous noise levels low. The periodic nature ensures that ion collection occurs during the pulse when voltage is applied, and the system resets during the off-period, maintaining measurement accuracy without requiring continuously high voltage.
Solution Approach 2:
The patent applies voltage pulses in advance of the actual measurement window, creating ions before the measurement is taken. This preliminary ionization ensures that when the measurement occurs, sufficient ions are already present in the chamber, allowing accurate detection even with low continuous voltage levels. The voltage pulse prepares the system in advance for the measurement phase.
3Duration of action of moving object
If continuous voltage is applied to maintain ion current, then the measurement continuity is improved, but the leakage current and temperature sensitivity increase
Solution Approach 1:
The patent implements periodic pulsed voltage operation where the ion chamber is actively measured during pulse windows and allowed to reset between pulses. This periodic cycle maintains measurement capability over time while providing regular intervals for system stabilization and leakage current reduction. The continuous repetition of measurement pulses ensures measurement continuity without requiring continuous high voltage application.
Solution Approach 2:
By using high-frequency pulsed voltage, the patent maintains continuous useful measurement action while minimizing the off-time between pulses. The measurement process continues uninterrupted through rapid pulse sequences, ensuring continuity of measurement capability while the brief intervals between pulses allow for leakage current reduction and system stabilization, improving overall reliability under field conditions.
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
This approach enhances the signal-to-noise ratio and improves measurement accuracy and reliability by reducing noise and leakage current effects, allowing for more precise detection of high-energy radiation flux.
Implementation Method 1
high-energy radiation, ionizing radiation are used in various applications... fluid capable of forming ions through the interaction of the fluid with high energy radiation... When a voltage is applied across the electrodes 15, 16 in the ion chamber 14, an electric field is created in the space between the electrodes. The ions move in response to the electric field
Implementation Method 2
When a voltage is applied across the electrodes 15, 16 in the ion chamber 14, an electric field is created in the space between the electrodes. The ions move in response to the electric field with the positive and negative ions pulled in opposite directions toward each electrode.
Data Source
AI summary
A method for measuring high-energy radiation flux, comprising applying a low voltage to electrodes in an ion chamber filled with a fluid capable of forming ions through the interaction of the fluid with high energy radiation; measuring an ion current signal related to an ion current induced by the low voltage; determining a leakage current; determining a gain; determining a magnitude of the high-energy radiation flux based on the ion current signal, gain, and leakage current; and outputting the result of the magnitude of the high-energy radiation flux.