Tritium monitor for realizing alpha, beta and gamma background deduction and tritium activity concentration detection method
By employing a dual-detector structure consisting of a gas-flow filament ionization chamber and a PIPS detector, combined with a signal processing unit, the problem of insufficient accuracy in tritium monitoring under complex environments is solved, and high-sensitivity tritium activity detection is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-03
- Publication Date
- 2026-03-10
AI Technical Summary
Existing tritium monitoring technologies struggle to accurately measure tritium activity in complex environments, especially lacking effective background subtraction methods when multiple radioactive backgrounds are present, resulting in insufficient measurement accuracy.
A dual-detector structure consisting of a flow-through filament-wall ionization chamber and a PIPS detector is adopted. Combined with microcurrent acquisition, signal amplification and discrimination, and difference processing units, the net tritium current is calculated to deduct the background interference of α, β, and γ radiation in the environment, thereby achieving accurate quantitative monitoring of tritium activity.
It significantly improves the accuracy and reliability of tritium monitoring, achieves high-sensitivity detection of tritium activity concentration, and can effectively distinguish tritium decay β particles from other radiation backgrounds in complex environments, reducing interference and improving detection accuracy.
Smart Images
Figure CN121634183A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of radioactive detection technology, specifically to a tritium monitor that basically achieves α, β, and γ background subtraction and a method for detecting tritium activity concentration. Background Technology
[0002] Tritium is a common radioactive isotope that primarily releases electrons through beta decay. Its beta particles have low energy (up to approximately 18.6 keV) and weak penetrating power, making it difficult to reach detectors through air or thin materials. Tritium is widely used in the nuclear industry and scientific research experiments, and its safe monitoring is of great significance. The low-energy beta characteristics of tritium pose certain challenges to the practical application of traditional radioactive detection equipment.
[0003] Existing tritium monitoring technologies mainly include liquid scintillation counting, thin-window gas flow cytometry, and semiconductor detectors. While liquid scintillation counting is sensitive to low-energy beta particles, it suffers from drawbacks such as complex operation, time-consuming sample preparation, and inconvenience for continuous online monitoring. Thin-window gas flow cytometry can respond to tritium beta particles, but in real-world environments, interference from alpha, beta, and gamma radiation from other radionuclides limits the accuracy of tritium measurements. Although semiconductor detectors can improve the response to high-energy beta and gamma radiation, their sensitivity to low-energy beta particles (such as tritium decay beta particles) is limited. Furthermore, in the presence of multiple radioactive backgrounds, there is a lack of effective background subtraction methods, resulting in insufficient accuracy of tritium monitoring in complex environments. Summary of the Invention
[0004] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a tritium monitor that can accurately measure tritium in complex environments.
[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A tritium monitor for α, β, and γ background subtraction includes detector I, detector II, and a signal processing unit. Detector I detects α particles, β particles, and γ particles, including tritium decay β particles and high-energy β particles with energies higher than tritium decay β particles, and outputs signal I corresponding to the total ionization current. Detector II detects α particles, γ particles, and high-energy β particles and outputs signal II corresponding to the count rate of each particle. The signal processing unit is electrically connected to detector I and detector II, respectively. The signal processing unit is configured to receive signal I and signal II, and calculate the background equivalent current jointly generated by α particles, γ particles, and high-energy β particles based on signal II and a preset calibration coefficient. Based on the difference between the total ionization current and the background equivalent current, the net tritium current is obtained, and the tritium activity concentration is determined based on the net tritium current.
[0006] In this invention, by setting up two different particle detectors and utilizing the differences in their responses to different particle energy ranges and particle types, the output signals of the two detectors are calculated. This effectively distinguishes tritium decay β particles from other α, β, and γ background radiation in the environment, thereby reducing background interference, improving the detection accuracy of tritium activity concentration, and achieving precise quantitative monitoring of tritium radiation.
[0007] As an optimization, particle detector I includes a flow-through filament-walled ionization chamber, and particle detector II includes a PIPS detector. These two detectors complement each other in their response performance to tritium decay β particles and high-energy α, β, and γ particles, thereby enhancing the detection capability of tritium activity concentration and improving the accuracy of background subtraction.
[0008] As an optimization, the signal processing unit includes a micro-current acquisition circuit, a signal amplification and discrimination circuit, and a processing module. The micro-current acquisition circuit is electrically connected to the airflow-type wire-wall ionization chamber and is used to convert signal I into a signal that can be processed by the processing module. The signal amplification and discrimination circuit is electrically connected to the PIPS detector and is used to amplify, discriminate, and convert signal II into a digital pulse signal. The processing module is electrically connected to both the micro-current acquisition circuit and the signal amplification and discrimination circuit and is used to perform the calculation. This allows for the acquisition, amplification, discrimination, and digitization of different types of signals from the two detectors, with the calculations being uniformly performed by the processing module.
[0009] As an optimization, the micro-current acquisition circuit includes a conversion circuit and an ADC circuit electrically connected together. The conversion circuit converts the current signal of signal I into a voltage signal, and the ADC circuit converts the voltage signal into a digital signal. This allows for the stable conversion of the extremely weak current signal generated by the airflow-type filament ionization chamber into a voltage signal and further digitization.
[0010] As an optimization, the tritium monitor also includes an alarm module, which is electrically connected to the signal processing unit. When the detected tritium activity concentration exceeds a preset alarm threshold, the signal processing unit can control the alarm module to emit an audible, visual, and / or vibration alarm. When the tritium activity concentration exceeds the preset threshold, it can automatically trigger audible, visual, or vibration alerts, achieving real-time early warning.
[0011] As an optimization, the tritium monitor also includes a display module, which is electrically connected to the signal processing unit. The display module can receive signals from the signal processing unit and display the tritium activity concentration in real time, allowing staff to intuitively obtain the current monitoring results.
[0012] As an optimization, the tritium monitor also includes a data storage module electrically connected to the signal processing unit. The data storage module receives signals from the signal processing unit and stores historical measurement data. The signal processing unit can also read the historical measurement data from the data storage module and display it through the display module. This allows for long-term storage of historical measurement data and the retrieval and display of this historical data, thereby supporting trend analysis, source tracing analysis, and data archiving.
[0013] As an optimization, the tritium monitor also includes a power management module, which comprises a lithium battery and a charging circuit. The lithium battery powers the tritium monitor, and can be charged via an external power source. The charging circuit allows for convenient external charging, facilitating extended use.
[0014] A method for detecting tritium activity concentration using the aforementioned tritium monitor involves acquiring the total ionization current and the count rates of α particles, γ particles, and high-energy β particles measured by detector I and detector II. Based on the count rates and pre-stored calibration coefficients, the background equivalent current generated by α particles, γ particles, and high-energy β particles is calculated. The background equivalent current is subtracted from the total ionization current to obtain the net tritium current, and the tritium activity concentration is determined based on the net tritium current.
[0015] As an optimization, the tritium monitor is placed in a known background radiation field, and the calibration coefficients of alpha particles, gamma particles, and high-energy beta particles are determined by multiple linear regression fitting; the tritium monitor is introduced into a tritium atmosphere with a known tritium activity concentration, and the tritium response coefficient is determined based on the net tritium current obtained by measurement calculation.
[0016] Compared with existing technologies, this invention adopts a dual-detector structure combining a flow-type wire-wall ionization chamber and a PIPS detector, and is equipped with signal processing units such as micro-current acquisition, electrical signal amplification and discrimination, and difference processing. This effectively eliminates the background interference of α, β, and γ radiation in the environment, thereby significantly improving the accuracy and reliability of tritium monitoring and achieving high-sensitivity detection of tritium activity concentration. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the structural principle of the present invention. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0019] like Figure 1 As shown, the tritium monitor for α, β, and γ background subtraction in this specific embodiment includes detector I, detector II, and a signal processing unit. Detector I is used to detect α particles, β particles, and γ particles, where β particles include tritium decay β particles and high-energy β particles with energies higher than tritium decay β particles, and outputs signal I corresponding to the total ionization current. Detector II is used to detect α particles, γ particles, and high-energy β particles, and outputs signal II corresponding to the count rate of each particle. The signal processing unit is electrically connected to detector I and detector II respectively. The signal processing unit is configured to receive signal I and signal II, and calculate the background equivalent current jointly generated by α particles, γ particles, and high-energy β particles based on signal II and a preset calibration coefficient. Based on the difference between the total ionization current and the background equivalent current, the net tritium current is obtained, and the tritium activity concentration is determined based on the net tritium current.
[0020] The particle detector I includes a flow-through wire-wall ionization chamber, and the particle detector II includes a PIPS detector.
[0021] The signal processing unit includes a micro-current acquisition circuit, a signal amplification and discrimination circuit, and a processing module. The micro-current acquisition circuit is electrically connected to the airflow-type filament ionization chamber and is used to convert the signal I into a signal that can be processed by the processing module. The signal amplification and discrimination circuit is electrically connected to the PIPS detector and is used to amplify, discriminate, and convert the signal II into a digital pulse signal. The processing module is electrically connected to both the micro-current acquisition circuit and the signal amplification and discrimination circuit and is used to perform the calculation.
[0022] The microcurrent acquisition circuit includes a conversion circuit and an ADC circuit electrically connected together. The conversion circuit is used to convert the current signal of signal I into a voltage signal, and the ADC circuit is used to convert the voltage signal into a digital signal.
[0023] The tritium monitor also includes an alarm module, which is electrically connected to the signal processing unit. When the detected tritium activity concentration exceeds a preset alarm threshold, the signal processing unit can control the alarm module to emit sound, light, and / or vibration alarms.
[0024] The tritium monitor also includes a display module, which is electrically connected to the signal processing unit. The display module can receive signals from the signal processing unit and display the tritium activity concentration in real time.
[0025] The tritium monitor also includes a data storage module, which is electrically connected to the signal processing unit. The data storage module can receive signals from the signal processing unit and store historical measurement data. The signal processing unit can also read the historical measurement data in the data storage module and display it through the display module.
[0026] The tritium monitor also includes a power management module, which includes a lithium battery and a charging circuit. The lithium battery is used to power the tritium monitor, and the lithium battery can be charged by an external power source through the charging circuit.
[0027] A method for detecting tritium activity concentration using the aforementioned tritium monitor involves acquiring the total ionization current and the count rates of α particles, γ particles, and high-energy β particles measured by detector I and detector II. Based on the count rates and pre-stored calibration coefficients, the background equivalent current generated by α particles, γ particles, and high-energy β particles is calculated. The background equivalent current is subtracted from the total ionization current to obtain the net tritium current, and the tritium activity concentration is determined based on the net tritium current.
[0028] The tritium monitor is placed in a known background radiation field, and the calibration coefficients for alpha particles, gamma particles, and high-energy beta particles are determined by multiple linear regression fitting. The tritium monitor is then introduced into a tritium atmosphere with a known tritium activity concentration, and the tritium response coefficient is determined based on the net tritium current obtained by measurement and calculation.
[0029] In the specific implementation process, two detectors with different types and functions are used as the core sensing part. Detector I adopts a gas-flow filament-wall ionization chamber structure, which can respond to alpha particles, beta particles (including low-energy beta particles produced by tritium decay and beta particles with higher energy), and gamma particles at the same time. All incoming particles are ionized in the gas, and these ionization effects are "accumulated" into a very small continuous current. Detector II uses a PIPS detector, which is very sensitive to alpha particles, gamma particles, and high-energy beta particles with energies higher than tritium beta, but has a weak response to low-energy beta particles produced by tritium decay.
[0030] The signal processing unit is divided into two independent channels, each corresponding to one of the two detectors. The input of the micro-current acquisition circuit is connected to the output of the airflow filament ionization chamber. It converts extremely weak current into voltage, amplifies and low-pass filters the converted voltage signal to remove high-frequency noise, and finally converts it into a digital signal through a high-precision analog-to-digital converter (ADC) before sending it to the subsequent processing module. The input of the signal amplification and discrimination circuit is connected to the output of the PIPS detector. It amplifies the weak charge pulses output by the PIPS detector, then sets a voltage threshold through a discriminator to filter out small-amplitude pulses such as circuit noise, and shapes the effective radiation pulses into standard digital pulses.
[0031] The processing module is implemented using a low-power microcontroller (MCU). The MCU directly receives the total radiation digital signal from the micro-current acquisition circuit and the background pulse signal from the signal amplification and discrimination circuit. Using internally stored background subtraction and dose calculation programs, the MCU reads data from the two detectors and performs numerical calculations to obtain the tritium activity concentration. The processing module stores a preset alarm threshold for tritium activity concentration. When the calculated tritium activity concentration exceeds the threshold, the processing module immediately controls the alarm module to perform corresponding actions. The alarm module integrates a buzzer (audible alarm), an LED (visual alarm), and a miniature vibration motor (vibration alarm), which can be activated individually or in combination to ensure effective user alerts even in noisy environments.
[0032] The display module uses an OLED or LCD screen, which can convert information such as tritium activity concentration, count rate of alpha particles, gamma particles, high-energy beta particles, battery power, and time into display driving signals to drive the screen for real-time display.
[0033] The data storage module stores historical measurement data, which may include tritium activity concentration, count rates of alpha, gamma, and high-energy beta particles, battery level, and time. The processing module can read this historical data and view it via the display module, or upload it via the communication module. The communication module is electrically connected to the signal processing unit, which can read the historical measurement data from the data storage module and transmit the data via the communication module. The communication module is either an infrared communication circuit or an RS485 serial communication circuit. The power management module uses a rechargeable polymer lithium battery to power all circuit modules within the tritium monitor. The charging circuit can be connected to an external charger via a Micro-USB interface to charge the lithium battery.
[0034] During the use of the tritium monitor, the current measured by the ionization chamber detector is contributed by tritium and other background radiation. The total ionization current is: I_total = I_tritium + I_bg; I_total: Total current in the ionization chamber; I_bg: The equivalent current of the PIPS detector calculated based on the calibration coefficient.
[0035] Background radiation includes radon, thorium and their daughter particles (alpha particles), high-energy beta particles, and gamma rays, which generate the current in the ionization chamber: I_bg = I_α + I_β_h + I_γ; I_α is the ionization current generated by radon-thorium and its alpha daughter particles; I_β_h is the ionization current of high-energy β particles; I_γ is the ionization current generated by gamma rays.
[0036] The ionization chamber detector and the anti-coincidence PIPS detector are connected in close series, allowing them to sample almost identical gas samples. The ionization chamber output is current, while the anti-coincidence PIPS detector has extremely low efficiency in detecting tritium β particles with an average energy of only 5.7 keV, which can even be ignored; its output is the count rate. Background radiation exhibits a fixed proportional relationship in the responses of both detectors. The following relationship is established: I_bg = k_α * C_α + k_β_h * C_β_h + k_γ * C_γ C represents the PIPS output count rate.
[0037] k_α: Alpha particle calibration coefficient. Represents the amount of ionizing current generated in the ionization chamber for each alpha count recorded on the PIPS detector. Units are A / cps (amperes per count per second).
[0038] k_β: High-energy β calibration coefficient. It represents the amount of ionizing current generated in the ionization chamber for each high-energy β count recorded on the PIPS detector. The unit is also A / cps.
[0039] k_γ: High-energy gamma calibration coefficient. Represents the amount of ionizing current generated in the ionization chamber for each gamma count recorded on the PIPS detector. The unit is also A / cps.
[0040] Place the instrument in the radon chamber and seal it.
[0041] Different concentrations of radon gas were injected, and the radioactive progeny was allowed to reach equilibrium at each concentration point (approximately 3-4 hours). After the measurements were completed, a dataset containing multiple sets of data was obtained. The dataset was then fitted using the multiple linear regression analysis tool MATLAB to calculate the values of the three coefficients k_α, k_β, and k_γ that best fit all the data points.
[0042] Calculate the pure tritium current: Subtract the fitted background current from the total current: I_tritium = I_total - I_bg; The tritium response coefficient k_tritium was calculated by calibration in tritium gas of different concentrations: k_tritium = A_tritium_cal / I_tritium_cal A_tritium_cal: The known activity concentration of standard tritium gas; I_tritium_cal: Tritium current calculated from standard tritium gas with known activity concentration.
[0043] For measuring unknown tritium concentration, the product of tritium current and tritium response coefficient is used. A_tritium = k_tritium * I_tritium, unit: Bq / m³.
[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.
Claims
1. A tritium monitor implementing α, β, γ background subtraction, characterized in that: The particle detector I comprises a flow gas wire wall ionization chamber, and the particle detector II comprises a PIPS detector.
2. The tritium monitor for realizing α, β, γ background deduction according to claim 1, characterized in that: The signal processing unit comprises a micro-current acquisition circuit, a signal amplification and discrimination circuit, and a processing module.
3. The tritium monitor for realizing α, β, γ background deduction according to claim 2, characterized in that: The micro-current acquisition circuit comprises a conversion circuit and an ADC circuit electrically connected together.
4. The tritium monitor for realizing α, β, γ background deduction according to claim 3, characterized in that: The tritium monitor further comprises an alarm module electrically connected to the signal processing unit.
5. The tritium monitor for realizing α, β, γ background deduction according to claim 1, characterized in that: The tritium monitor further comprises a display module electrically connected to the signal processing unit.
6. The tritium monitor for realizing α, β, γ background deduction according to claim 1, characterized in that: The tritium monitor further comprises a data storage module electrically connected to the signal processing unit.
7. The tritium monitor for realizing α, β, γ background deduction according to claim 6, characterized in that: The tritium monitor further comprises a power management module comprising a lithium battery and a charging circuit.
8. The tritium monitor for realizing α, β, γ background deduction according to any one of claims 1 to 7, characterized in that: The total ionization current and the count rates of the alpha particles, the gamma particles, and the high-energy beta particles measured by the particle detector I and the particle detector II are obtained, the background equivalent current generated by the alpha particles, the gamma particles, and the high-energy beta particles is calculated based on the count rates and the pre-stored calibration coefficient, the net tritium current is obtained by deducting the background equivalent current from the total ionization current, and the tritium activity concentration is determined based on the net tritium current.
9. A method for detecting the activity concentration of tritium by using the tritium monitor according to any one of claims 1 to 8, characterized in that: 10. The method of claim 9, wherein: The tritium monitor is placed in a known background radiation field, and calibration coefficients of alpha particles, gamma particles and high-energy beta particles are determined through multiple linear regression fitting; the tritium monitor is connected to a tritium gas atmosphere with a known tritium activity concentration, and a tritium response coefficient is determined based on a net tritium current obtained through measurement calculation.