A bimodal noble gas radionuclide measurement system and method

Abstract

The application provides a bimodal inert gas radionuclide measurement system and method, and particularly relates to the technical field of nuclear radiation detection. The measurement system comprises a coincidence probe, a power supply unit, a data acquisition unit and an upper computer. The coincidence probe comprises a PIPS gas detection chamber and a cadmium zinc telluride detector array. The cadmium zinc telluride detector array is arranged on the outer side of the PIPS gas detection chamber, and the detection surface thereof is opposite to the gas sample in the PIPS gas detection chamber. The power supply unit is used for supplying power to the PIPS gas detection chamber and / or the cadmium zinc telluride detector array. The data acquisition unit is used for acquiring and processing the detector signal. The upper computer is used for analyzing the data processed by the data acquisition unit, and controlling the operation of the coincidence probe and the data acquisition unit. The measurement system of the application can be switched between the xenon monitoring mode and the krypton monitoring mode, greatly reducing the comprehensive construction cost, land space and operation and maintenance complexity of the monitoring system, and improving the equipment utilization.

Description

Technical Field

[0001] This invention relates to the field of nuclear radiation detection technology, and in particular to a dual-mode inert gas radionuclide measurement system and method. Background Technology

[0002] Isotopes of the radioactive inert gases krypton (Kr) and xenon (Xe) are crucial characteristic indicators in the field of nuclear activity monitoring. Among them, krypton-85 (Kr-85) is a particularly important characteristic indicator. 85 Xenon (Kr) serves as a clear fingerprint signal of the nuclear fuel reprocessing process, and its activity concentration in the atmosphere is a key parameter for tracking and quantifying reprocessing activities; a series of radioactive xenon isotopes (such as...) 133 Xe, 131m Xe, 133m Xe, 135 Xe and other radioactive krypton isotopes are core characteristic signals for nuclear explosion detection, and accurate monitoring of them is an important part of nuclear activity verification. Therefore, achieving highly sensitive, selective, and rapid measurement of ultra-trace levels of radioactive krypton and xenon isotopes in the environment has significant practical importance and application value for environmental safety monitoring of nuclear facilities and nuclear activity verification.

[0003] Currently, the existing monitoring technologies for measuring radioactive xenon and radioactive krypton have formed two independent technical paths with completely different principles.

[0004] For the measurement of radioactive xenon isotopes, the industry generally adopts β-γ coincidence measurement technology to effectively reduce the measurement background and improve the signal-to-noise ratio, thereby achieving ultra-trace level detection. Existing radioactive xenon measurement systems (such as SAUNA and ARSA) use a combination of plastic scintillators and NaI(Tl) detectors. Although the technology is relatively mature, the poor energy resolution of the NaI(Tl) detector limits its ability to distinguish xenon characteristic rays with similar energies (such as 81 keV gamma rays and 30 keV X-ray groups). Furthermore, plastic scintillators exhibit a significant memory effect, which affects the accuracy of subsequent measurements. While high-purity germanium (HPGe) spectrometers offer excellent resolution, these instruments typically rely on liquid nitrogen cooling, resulting in large size and high maintenance costs, making them unsuitable for rapid on-site monitoring needs.

[0005] For krypton-85, which undergoes near-pure beta decay, a completely different technical approach is employed compared to the measurement of radioactive xenon. Due to its extremely low branching ratio of gamma rays, gamma spectroscopy measurement techniques have an extremely high detection limit. While liquid scintillation counting methods for beta measurements have a lower detection limit, they can achieve ultra-trace levels. 85 While Kr can be detected, there are difficulties in automatically transferring samples into the scintillation fluid, making it hard to meet the actual needs of online monitoring.

[0006] In summary, the current technical landscape for monitoring radioactive krypton and xenon isotopes has prominent problems: because the two measurement techniques are independent, two sets of monitoring equipment with different principles and independent operation are often required in actual monitoring. This not only significantly increases the cost of equipment construction and the complexity of operation and maintenance, but also makes it difficult to meet the actual needs of efficient, economical and integrated nuclear activity monitoring.

[0007] Therefore, there is an urgent need to develop a measurement system and method that can achieve integrated and highly sensitive measurement of radioactive krypton and xenon isotopes. Summary of the Invention

[0008] In view of the shortcomings of the prior art, the present invention provides a dual-mode inert gas radionuclide measurement system and method to solve the technical problem that the monitoring of radioactive krypton and xenon isotopes cannot be integrated.

[0009] To achieve the above and other related objectives, this invention provides a dual-mode inert gas radionuclide measurement system. The system includes a coincidence probe, a power supply unit, a data acquisition unit, and a host computer. The coincidence probe comprises a PIPS gas detection chamber and a cadmium zinc telluride (CZT) detector array. The CZT detector array is located outside the PIPS gas detection chamber, and its detection surface faces the gas sample inside the PIPS gas detection chamber. The power supply unit is electrically connected to both the PIPS gas detection chamber and the CZT detector array, providing power to both. The data acquisition unit is communicatively connected to both the PIPS gas detection chamber and the CZT detector array, and is used to acquire and process detector signals. The host computer is communicatively connected to the data acquisition unit, and is used to analyze the data processed by the data acquisition unit and control the operation of the coincidence probe and the data acquisition unit. The dual-mode inert gas radionuclide measurement system can switch between a first operating mode and a second operating mode. In the first working mode, the power supply unit simultaneously supplies power to the PIPS gas detection chamber and the cadmium zinc telluride detector array, the data acquisition unit synchronously acquires signals from the PIPS gas detection chamber and the cadmium zinc telluride detector array, and the host computer completes data analysis based on the time conformity relationship between the two types of signals. In the second operating mode, the power supply unit supplies power to the PIPS gas detection chamber, the data acquisition unit acquires the signal output by the PIPS gas detection chamber, and the host computer performs data analysis based on the β energy spectrum of the PIPS gas detection chamber.

[0010] In one embodiment of the present invention, the PIPS gas detection chamber includes a housing, a first PIPS detector and a second PIPS detector. The housing includes an aluminum alloy support frame and a carbon fiber plate fixed on the aluminum alloy support frame. The first PIPS detector and the second PIPS detector are mounted opposite each other on the inner wall of the carbon fiber plate, and a sealed sample gas chamber is formed between the first PIPS detector and the second PIPS detector.

[0011] In one embodiment of the present invention, the cadmium zinc telluride detector array includes at least a first cadmium zinc telluride detector and a second cadmium zinc telluride detector, which are respectively installed in the outer central regions of the two carbon fiber plates.

[0012] In one embodiment of the present invention, the data acquisition unit is a digital pulse analyzer based on a field-programmable gate array (FPGA). The FPGA-based FPGA digital pulse analyzer has at least four independent acquisition channels, each acquisition channel corresponding to the acquisition of a detector signal. The FPGA-based FPGA digital pulse analyzer records the channel number, energy, and timestamp information of each detection event in a list mode.

[0013] In one embodiment of the present invention, the host computer includes a dual-mode analysis algorithm library, which includes a coincidence spectrum analysis algorithm for the first working mode and a β spectrum analysis algorithm for the second working mode.

[0014] In one embodiment of the present invention, the dual-mode inert gas radionuclide measurement system further includes a shield that surrounds the coincidence probe, and the shield includes a lead layer, a cadmium layer and a copper layer from the outside to the inside; the gas path control unit is connected to the PIPS gas detection chamber.

[0015] In one embodiment of the present invention, the dual-mode inert gas radionuclide measurement system further includes a gas path control unit, which is used to control the injection and discharge of gas samples and is electrically connected to the host computer.

[0016] The present invention also provides a method for measuring radionuclides in a dual-mode inert gas, the method comprising the following steps: Receive mode selection command and determine whether the working mode is the first working mode or the second working mode; The configuration of the power supply unit and data acquisition unit is controlled according to the selected operating mode; Perform sample measurements and process the collected data according to the data analysis method corresponding to the selected working mode to obtain the activity concentration of the target nuclide.

[0017] In one embodiment of the present invention, when the working mode is the first working mode, the data analysis method includes: Acquire list pattern data from the PIPS gas detection chamber and the cadmium zinc telluride detector array; Based on a preset coincidence time window, coincidence correlation is performed on γ / X-ray events from the cadmium zinc telluride detector and β events from the PIPS gas detection chamber to generate coincidence energy spectra. Analyze the characteristic peaks in the coincidence spectrum to calculate the activity concentration of the radioactive xenon isotope.

[0018] In one embodiment of the present invention, when the working mode is the second working mode, the data analysis method includes: Acquire β-spectral data from the PIPS gas detection chamber; The net count rate is obtained by integrating the β energy spectrum within a set energy range. The activity concentration of radioactive krypton-85 was calculated based on the total detection efficiency of the PIPS gas detection chamber for the target β nuclide.

[0019] In one embodiment of the present invention, before the step of performing sample measurement, the measurement method further includes a step of using background gas to perform background measurement on the system; when calculating the activity concentration, the corresponding background count is deducted.

[0020] The beneficial effects of this invention are as follows: The dual-mode inert gas radionuclide measurement system proposed in this invention integrates a PIPS (passivated ion-implanted silicon) detector and a CZT (cadmium zinc telluride) detector on a single hardware platform, achieving intelligent switching between a "β-γ coincidence measurement mode" and a "pure β measurement mode" through reconfigurable electronic design. The β-γ coincidence measurement mode is used for the precise detection of various radioactive xenon isotopes, while the pure β measurement mode, by shutting down the CZT detector and activating only the PIPS detector, transforms the system into a dedicated krypton-85 β spectrometer. This solves the drawback of requiring two independent devices in traditional technologies, significantly reducing the overall construction cost, footprint, and maintenance complexity of the monitoring system, and improving equipment utilization.

[0021] In xenon isotope measurement mode, this measurement system fully leverages the advantages of the high energy resolution of the CZT detector and the extremely low background of the conformation measurement technology, effectively improving the sensitivity and selectivity of xenon isotope measurement. It can accurately identify xenon characteristic rays with adjacent energies, solving the problem of insufficient resolution of traditional NaI(Tl) detectors and meeting the requirements for precise measurement of ultra-trace xenon isotopes.

[0022] In Krypton-85 measurement mode, the system transforms into a β-spectrum based on a PIPS detector. By shutting down the CZT detector, the main background interference it causes is completely eliminated. Compared with traditional flow-gas proportional counters, it has better energy resolution and lower background potential, effectively identifying background interference and significantly improving the detection sensitivity of Krypton-85.

[0023] The measurement system of this application, through intelligent software design, realizes one-click mode switching and fully automatic measurement and analysis, simplifies the operation process, lowers the threshold for use, and greatly improves the efficiency and convenience of nuclear activity monitoring.

[0024] The measurement system of this application has a compact structure and strong adaptability: it adopts PIPS-BOX as an integrated gas detection chamber, combined with CZT layout and integrated shielding design, making the whole system compact, robust and reliable. It is not only suitable for fixed monitoring scenarios in laboratories, but also meets the diverse monitoring needs of on-site and mobile monitoring, thus broadening the application scope of the system. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0026] In the attached diagram: Figure 1 This is a schematic diagram of the overall structure of a dual-mode inert gas radionuclide measurement system provided in one embodiment of the present invention; Figure 2 This is a schematic diagram of the dual-mode inert gas radionuclide measurement system provided in one embodiment of the present invention after the housing has been removed. Figure 3 This is a schematic diagram of the PIPS gas detection chamber structure of a dual-mode inert gas radionuclide measurement system provided in one embodiment of the present invention; Figure 4 This is a cross-sectional schematic diagram of the PIPS gas detection chamber of a dual-mode inert gas radionuclide measurement system provided in one embodiment of the present invention; Figure 5 This is a schematic diagram showing the interaction between the PIPS gas detection chamber and the cadmium zinc telluride detector array in a dual-mode inert gas radionuclide measurement system provided in one embodiment of the present invention. Figure 6 This is a schematic diagram of the internal structure of the coincident probe of a dual-mode inert gas radionuclide measurement system provided in one embodiment of the present invention; Figure 7This is an architectural diagram of a dual-modal inert gas radionuclide measurement system provided in one embodiment of the present invention; Figure 8 This is an electronic and data flow block diagram of a dual-mode inert gas radionuclide measurement system provided in one embodiment of the present invention; Figure 9 This is a flowchart of a measurement method for a dual-mode inert gas radionuclide measurement system provided in one embodiment of the present invention; Figure 10 This is a dual-mode flowchart of the measurement method of the dual-mode inert gas radionuclide measurement system provided in one embodiment of the present invention.

[0027] The attached figures are labeled as follows: 100. Detector; 110. PIPS gas detection chamber; 111. Housing; 1111. Aluminum alloy support frame; 1112. Carbon fiber plate; 112. First PIPS detector; 113. Second PIPS detector; 114. Inlet pipe; 115. Outlet pipe; 120. Cadmium zinc telluride detector array; 121. First cadmium zinc telluride detector; 122. Second cadmium zinc telluride detector; 200. Data acquisition unit; 210. Charge-sensitive preamplifier; 300. Shielding; 400. Relay control board; 500. Housing; 510. Inlet; 511. Inlet solenoid valve; 520. Outlet; 521. Outlet solenoid valve; 530. Switch; 540. Power input interface; 550. USB interface; 560. Ethernet port. Detailed Implementation

[0028] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0029] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0031] The terms or phrases used in this article have the following meanings: In this article, the terms "multiple," "various," and "multiple times" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0032] In this document, terms such as “preferred,” “ideal,” “further,” “even more,” and “particularly” are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0033] In this document, when referring to numerical ranges, unless otherwise specified, the distribution of selectable values ​​within a numerical range is considered continuous, including the two endpoints of the range (i.e., the minimum and maximum values), and every value between these two endpoints. When multiple numerical ranges are provided to describe a feature or property, these numerical ranges can be combined.

[0034] This invention provides a dual-mode inert gas radionuclide measurement system and method. The system utilizes a passivated ion-implanted silicon (PIPS) detector and a cadmium zinc telluride (CZT) detector to construct a coincidence detection architecture. By introducing a reconfigurable electronic control module and intelligent software, a dual-mode operating mechanism is designed to achieve intelligent switching and stable operation between a "β-γ coincidence measurement mode" and a "pure β measurement mode." The β-γ coincidence measurement mode is used for the precise detection of various radioactive xenon isotopes, fully inheriting and leveraging the inherent performance advantages of the PIPS+CZT coincidence detection system to ensure high sensitivity and high selectivity in xenon isotope measurement. The β measurement mode, by shutting down the CZT detector and activating only the PIPS detector, can quickly transform the system into a dedicated krypton-85 β spectrometer, thus efficiently integrating the previously separate monitoring functions of radioactive xenon and krypton-85 on a single hardware platform. This invention fundamentally solves the many drawbacks of the discrete equipment in traditional monitoring technologies, achieving a technological breakthrough of "dual-function in one machine," and enabling efficient and accurate monitoring of two types of target nuclides on a single hardware platform.

[0035] Please see Figures 1 to 5The aforementioned dual-mode inert gas radionuclide measurement system includes: a coincidence probe 100, a power supply unit (not shown in the figure), a data acquisition unit 200, and a host computer (not shown in the figure). The coincidence probe 100 includes a PIPS gas detection chamber (PIPS-BOX) 110 and a cadmium zinc telluride (CZT) detector array 120. The CZT detector array 120 is located outside the PIPS gas detection chamber 110, and its detection surface is opposite to the gas sample inside the PIPS gas detection chamber 110. The power supply unit is connected to the PIPS gas detection... The measurement chamber 110 and the cadmium zinc telluride detector array 120 are electrically connected to provide power to the PIPS gas detection chamber 110 and / or the cadmium zinc telluride detector array 120. The data acquisition unit 200 is communicatively connected to both the PIPS gas detection chamber 110 and the cadmium zinc telluride detector array 120, and is used to acquire and process signals from each detector. The host computer is communicatively connected to the data acquisition unit 200, and is used to analyze the data processed by the data acquisition unit 200 and control the operation of the probe 100 and the data acquisition unit 200. The dual-mode inert gas radionuclide measurement system of this invention can switch between a first operating mode and a second operating mode. In the first working mode, the power supply unit simultaneously supplies power to the PIPS gas detection chamber 110 and the cadmium zinc telluride detector array 120. The data acquisition unit 200 synchronously acquires the signals from the PIPS gas detection chamber 110 and the cadmium zinc telluride detector array 120. The host computer completes data analysis based on the time conformity relationship between the two types of signals. In the second working mode, the power supply unit supplies power to the PIPS gas detection chamber 110, the data acquisition unit 200 acquires the signal output by the PIPS gas detection chamber 110, and the host computer completes data analysis based on the β energy spectrum of the PIPS gas detection chamber 110.

[0036] Please see Figure 3 and Figure 4Specifically, the PIPS gas detection chamber 110 is used to contain the gas sample to be tested. Its structural design balances sealing performance, mechanical strength, and detection performance. It includes a shell 111, a first PIPS detector 112, and a second PIPS detector 113. The shell 111 is composed of an aluminum alloy support frame 1111 and a carbon fiber plate 1112. The aluminum alloy support frame 1111 serves as the core support structure of the chamber, and its shape is adapted to the overall shape of the PIPS gas detection chamber 110. Various structural forms such as disc, cube, and cylinder can be selected to adapt to different application scenarios. The carbon fiber plate 1112 is fixed to the aluminum alloy support frame 1111, and together with the aluminum alloy support frame 1111, they enclose a sealed cavity structure. This design can ensure the mechanical strength and sealing performance required by the chamber, while minimizing the absorption of β particles and low-energy photons by the shell 111, thus avoiding affecting the detection accuracy. The first PIPS detector 112 and the second PIPS detector 113 are mounted opposite each other on the carbon fiber plate 1112, forming a flat gas cavity between the two PIPS detectors. The inner height of the cavity is set to 0.5 cm to 8.0 cm. Under standard measurement conditions, the effective volume of the cavity is not less than 4.8 mL.

[0037] Furthermore, the PIPS gas detection chamber 110 is also provided with an inlet pipe 114 and an outlet pipe 115 for injecting and discharging the gas to be detected. For example, two precision-controlled threaded holes are machined on the side of the housing 111. Each threaded hole is connected to a VCR connector or Swagelok connector with an outer diameter of 2 mm and an inner diameter of 1 mm, which serve as the inlet pipe 114 and the outlet pipe 115, respectively. The selection of this connector can ensure the sealing during the gas transmission process, avoid gas leakage from affecting the measurement accuracy, and facilitate the disassembly and maintenance of the pipeline.

[0038] Please see Figure 3 and Figure 4In one specific embodiment, the PIPS gas detection chamber 110 adopts a disc-shaped structure. The outer shell 111 corresponding to the upper and lower large windows of the chamber is sealed by two carbon fiber plates 1112. The thickness of the carbon fiber plate 1112 can be flexibly set according to actual detection requirements without special limitations. For example, a thickness of 600μm or 800μm can be selected. The sealing method uses fluororubber O-rings in conjunction with metal pressure rings to achieve vacuum-level sealing, ensuring no leakage of gas samples in the chamber and guaranteeing the accuracy of the measurement. The inner wall of the outer shell 111 has a precision-controlled mounting slot. The first PIPS detector 112 and the second PIPS detector 113 are respectively installed on the upper and lower inner walls of the outer shell 111. The sensitive surfaces of the two are parallel to each other and arranged opposite each other. The distance between them can be adjusted by shims, with an adjustment range of 0.5 cm to 8.0 cm. Furthermore, the distance between the first PIPS detector 112 and the second PIPS detector 113 is 0.8 cm, at which point the effective cavity volume is approximately 10.6 mL, balancing detection efficiency and sample capacity. The detection signals from the first PIPS detector 112 and the second PIPS detector 113 are respectively led out through axial micro-hole connectors (e.g., Axial Microdot Female type connectors) to ensure signal transmission stability and anti-interference capabilities.

[0039] Please see Figure 5 The cadmium zinc telluride (CZN) detector array 120 is used to detect gamma rays and characteristic X-rays. This detector array consists of several (at least two) CZN detector units. In one embodiment, the CZN detector array 120 includes a first CZN detector 121 and a second CZN detector 122, which are symmetrically mounted at the outer center of the large windows on both sides of the PIPS gas detection chamber 110, with their respective detection surfaces facing the gas sample inside the chamber. For example, the first zinc-cadmium telluride detector 121 and the second zinc-cadmium telluride detector 122 are fixed to the outer shell 111 of the PIPS gas detection chamber 110 via detector brackets. The detector brackets are fixed to the outer shell 111, and the first zinc-cadmium telluride detector 121 and the second zinc-cadmium telluride detector 122 are respectively fixed in the upper and lower mounting positions of the detector brackets. This ensures that the beryllium window detection surface of each zinc-cadmium telluride detector is directly facing the central area of ​​the carbon fiber plate 1112 of the chamber shell, and that the distance between the detector end face and the carbon fiber plate 1112 is as small as possible (e.g., 2-3 mm) to maximize geometric detection efficiency. The signal lines of the zinc-cadmium telluride detectors are also led out via shielded cables.

[0040] In one embodiment, the first zinc-cadmium telluride detector 121 and the second zinc-cadmium telluride detector 122 adopt a hemispherical structure, which helps to improve charge collection efficiency, and the crystal size is not less than 10 mm × 10 mm × 5 mm (length × width × thickness). The detector housing adopts a thin beryllium window with a thickness of less than 0.5 mm to ensure good transmission of low-energy photons. Key performance indicators of the zinc-cadmium telluride detector include: energy range covering 10 keV ~ 2.0 MeV; for 137 The energy resolution of the 662 keV γ-rays from the Cs source is better than 1.2%; under continuous 8-hour operating conditions, the peak position shift is less than 1%.

[0041] Please see Figure 2 In one embodiment, the measurement system further includes a shield 300, in which the coincidence probe 100 (i.e., the PIPS gas detection chamber 110 and two cadmium zinc telluride detectors) is integrated and installed. The shield 300 employs a multi-layered composite structure of lead, cadmium, and copper, its core function being to effectively shield against ambient gamma rays and characteristic X-ray background, preventing environmental background interference with the accuracy of the measurement results. Specifically, the shield 300 is constructed from the outside in, consisting of a lead layer, a cadmium layer, and a copper layer, with the following thicknesses: 50 mm for the lead layer, 2 mm for the cadmium layer, and 1 mm for the copper layer. The cadmium and copper layers work together to absorb the characteristic X-rays generated by the lead layer itself, further reducing background interference and improving the shielding effect. The coincidence probe 100 is placed in the cavity at the center of the shield 300, and is fixed and buffered using low-radioactivity epoxy resin or silicone, ensuring the stability of the coincidence probe 100 installation and preventing mechanical vibration from affecting the detection performance. All connecting cables are led out through pre-designed wiring holes in the shield 300. These holes feature a labyrinthine structure and are filled with shielding material to effectively prevent radiation leakage and ensure the overall shielding effectiveness of the shield 300. Finally, the conformal probe 100 is integrated into a metal housing measuring approximately 35cm (length) × 22cm (width) × 13.5cm (height), achieving a compact structure and miniaturized system design for the conformal probe 100, facilitating subsequent installation, transportation, and practical application.

[0042] Please see Figure 6In one embodiment, each PIPS detector (first PIPS detector 112, second PIPS detector 113) and each cadmium zinc telluride (CZT) detector (first CZT detector 121, second CZT detector 122) is connected to a corresponding charge-sensitive preamplifier 210. This charge-sensitive preamplifier 210 can be an ORTEC 142A model or a functionally equivalent model. Each charge-sensitive preamplifier 210 is tightly integrated within the cavity of the shield 300 and positioned close to the corresponding detector to shorten the signal transmission path, thereby effectively reducing noise interference during signal transmission and ensuring the integrity and accuracy of the detection signal. Simultaneously, under room temperature operating conditions, the leakage current of the PIPS detector must meet the technical requirement of not exceeding 50nA to ensure the stability and detection accuracy of the detector operation.

[0043] Please see Figure 7 In one embodiment, the power supply unit includes a low-noise high-voltage module and a low-voltage module. The high-voltage module provides operating bias voltage for the PIPS detector and the CZT detector; the low-voltage module provides operating power for the preamplifier and system control circuit. Specifically, the typical operating voltage range of the PIPS detector is +15V to +70V, preferably set to +70V, which is provided by a programmable high-voltage module (e.g., CAEN A1525). The typical operating voltage of the CZT detector is approximately 900V, which is independently provided by another high-voltage module (e.g., CAEN A1525), enabling independent power supply control for the two detectors and improving power supply stability. The power supply for all high-voltage modules and the low-voltage power supply (including ±12V and +5V) for each charge-sensitive preamplifier 210 are centrally provided by a low-noise linear power board, ensuring power supply uniformity, stability, and low-noise characteristics, and avoiding power supply interference from affecting detection performance.

[0044] Please see Figure 2 and Figure 7In one embodiment, the data acquisition unit 200 employs a multi-channel digital pulse analyzer based on a field-programmable gate array (FPGA), such as the CAEN DT5730 desktop digitizer or an energy-efficient embedded module. This digital pulse analyzer has at least four independent acquisition channels, and each channel has at least 4096 channel addresses, meeting the requirements for simultaneous acquisition by multiple detectors. Its core function is to receive the analog detection signals output from each charge-sensitive preamplifier 210, perform high-speed analog-to-digital conversion (ADC) processing on the analog signals, and extract amplitude (corresponding to detection energy) information and precise timestamp information for each detection event in real time, achieving accurate acquisition and preliminary processing of the detection signals. All detection events are output in list mode format, that is, each detection event is recorded as a data tuple of "channel number-energy-timestamp" in chronological order, facilitating further analysis and processing of the data.

[0045] Furthermore, the digital pulse analyzer has four independent input channels, employs a 16-bit ADC resolution, and a sampling rate of up to 100 MS / s. Each input channel is connected to the output of a charge-sensitive preamplifier 210, enabling independent acquisition of each detection signal. The FPGA firmware is programmed and configured to perform real-time digital filtering, pole-zero compensation, and peak detection on the input pulse signals. It also adds a precise timestamp to each triggered detection event, with a resolution of up to 8 ns, ensuring accurate timing of the detection events. The detection data processed by the FPGA (including channel number, energy, and timestamp) is uploaded to a host computer in real-time via USB or Gigabit Ethernet in List Mode, facilitating data storage, analysis, display, and subsequent processing by the host computer.

[0046] Please see Figure 8In one embodiment, the measurement system further includes a gas path and control system (not shown in the figure). This system includes a micro-pump, a solenoid valve, a vacuum gauge, and tubing. Its core functions are to automatically inject sample gas, evacuate the PIPS gas detection chamber 110, circulate gas, and discharge waste gas. All of these actions can be automatically controlled via host computer software without manual intervention. In a specific implementation, the gas path is constructed using corrosion-resistant 1 / 8-inch outer diameter (OD) stainless steel tubing and VCR connectors to ensure the gas path's sealing, corrosion resistance, and structural stability, preventing gas leakage or corrosion from affecting measurement accuracy. A micro-diaphragm pump, a two-position three-way solenoid valve, a mass flow controller, and a vacuum gauge are connected in series in the gas path. These components work together to achieve precise control and status monitoring of the gas path. All pneumatic components are driven by a relay control board 400. The relay control board 400 establishes a communication connection with the host computer via a USB interface or serial port, receives control commands issued by the host computer software, and thus realizes a fully automated cycle of "vacuuming - sample filling - sealing measurement - exhaust", improving measurement efficiency and reducing human operation errors.

[0047] The host computer of this invention (not shown in the figure) is equipped with dedicated host computer software for a "dual-mode inert gas monitoring system". This host computer software can be developed and implemented based on the C# platform or the LabVIEW platform. Its core function is to realize dual-mode intelligent control, human-computer interaction and data processing and analysis of the system. The main interfaces and functions are as follows: Main control interface: The main control interface is equipped with function tabs such as "System Status", "Mode Selection", "Real-time Energy Spectrum" and "Data Analysis". The "Mode Selection" area has two prominent and directly operable control buttons for "Xenon (Xe) Monitoring Mode" and "Krypton (Kr) Monitoring Mode", which makes it easy for users to quickly switch the system working mode.

[0048] Hardware Parameter Management: The host computer software has a built-in parameter database for storing the operating parameters of each detector (PIPS detector, CZT detector), including but not limited to key parameters such as high voltage setpoint, amplifier gain, and signal polarity. When the user clicks the corresponding mode button in the "Mode Selection" area, the software can automatically call the preset parameter set corresponding to that mode and send control commands to the high voltage module and data acquisition card through the drive interface, automatically completing the hardware parameter configuration of the entire system without manual adjustment, thus improving the ease of operation and the accuracy of parameter configuration.

[0049] Data Acquisition and Display: The "Real-time Energy Spectrum" tab on the main control interface dynamically displays the energy spectrum information of the currently active detector. In Xenon (Xe) monitoring mode, the individual energy spectra of the first CZT detector, the second CZT detector, the first PIPS detector 112, and the second PIPS detector 113, as well as the coincidence energy spectra of each detector, are displayed simultaneously. In Krypton (Kr) monitoring mode, only the β energy spectra of the first PIPS detector 112 and the second PIPS detector 113 are displayed. Simultaneously, the list-mode data stream acquired by the system is stored in real-time to a binary file at a specified path on the hard drive, facilitating subsequent data retrieval, review, and further analysis and processing.

[0050] Dual-mode analysis algorithm library: The host computer software integrates two dedicated analysis algorithm modules, each adapted to one of the two monitoring modes, as detailed below: The coincidence measurement and analysis module is adapted for xenon (Xe) monitoring and includes functions such as coincidence time window setting (default value is 2μs, which can be flexibly adjusted according to actual measurement needs), coincidence event search algorithm, coincidence energy spectrum generation, automatic peak finding, nuclide library, net area calculation, and activity concentration calculation; among which, the nuclide library is built-in. 133 Xe, 131m Xe, 135 Key data such as decay information, characteristic ray energy, and branching ratio of target xenon isotopes like Xe provide data support for nuclide identification and activity calculation.

[0051] β Measurement and Analysis Module: This module is compatible with krypton (Kr) monitoring mode and includes functions such as β energy spectrum calibration, region of interest (ROI) setting, background spectrum acquisition and subtraction, net count rate calculation, efficiency factor (ε_β) input interface, and activity concentration calculation; among which, the region of interest (ROI) can be determined according to... 85 The β-ray energy characteristics of Kr can be flexibly set; for example, an energy range of 150 keV to 700 keV can be set as... 85 Kr's dedicated analysis area.

[0052] In summary, the host computer software, as the core component for realizing dual-mode intelligent control and human-computer interaction in this invention, has overall functions covering mode control and hardware management, data acquisition and storage, dual algorithm library integration, and parameter database management, as detailed below: (1) Mode control and hardware management: Provides an intuitive graphical operation interface for users to conveniently select the system working mode; the software automatically executes the corresponding hardware configuration process according to the mode selected by the user, including turning on and off the high voltage power supply, enabling and disabling the data acquisition channel, etc., to realize the automated management and control of the system hardware.

[0053] (2) Data acquisition and storage: The FPGA data acquisition unit 200 is controlled through the drive interface to receive the detection data transmitted by the FPGA in real time, and the data display, classification and storage are completed synchronously. The raw data in list mode or the energy spectrum data after processing can be selectively stored to ensure the integrity and traceability of the data.

[0054] (3) Dual Algorithm Library Integration: Two sets of dedicated analysis algorithms are integrated. One set is used for spectrum interpretation, target xenon isotope identification (based on the high-resolution spectrum characteristics of the CZT detector), and activity concentration calculation; the other set is used for the analysis of the β spectrum of the PIPS detector, background subtraction, and pure β nuclides (such as... 85 The activity concentration calculation of Kr can meet the monitoring needs of different inert gases.

[0055] (4) Parameter database management: The built-in key parameter library can store and calibrate core parameters such as the detection efficiency of different nuclides, the branching ratio of characteristic rays, and the volume of the PIPS gas detection chamber 110. It also supports parameter updates and calibration, ensuring the accuracy of activity concentration calculation.

[0056] Please see Figure 8 Through the control of the aforementioned host computer software, the measurement system of the present invention has two independent working modes, and the specific workflow is as follows: Mode 1: β-γ coincidence measurement mode (for monitoring radioactive xenon) When the user selects the "Xenon (Xe) monitoring mode" through the host computer software, the system control software sends control commands to the electronics system through the digital interface, simultaneously turning on the high-voltage power supplies of the two PIPS detectors (first PIPS detector 112 and second PIPS detector 113) and the two CZT detectors (first CZT detector and second CZT detector), so that all detectors are in normal working condition, and at the same time activating all four independent acquisition channels of the data acquisition unit 200.

[0057] The FPGA data acquisition system synchronously and continuously records the list-mode data output by four detectors according to preset parameters and transmits it to the host computer in real time. After receiving the raw list data, the host computer software automatically executes the digital coincidence algorithm. The specific processing flow is as follows: First, a coincidence time window in the nanosecond to microsecond range is set according to the measurement requirements (exemplarily set to 2μs); second, the software performs real-time retrieval on the received data stream. When any CZT detector records a γ-ray or characteristic X-ray event, within the set coincidence time window, it searches whether the two PIPS detectors synchronously record a β-particle event; if the corresponding β-particle event is found, the γ-ray or characteristic X-ray event is marked as a coincidence event; subsequently, the above coincidence retrieval operation is performed on the event data of the first CZT detector and the second CZT detector respectively to generate the first CZT coincidence energy spectrum and the second CZT coincidence energy spectrum; finally, the two coincidence energy spectra are superimposed to obtain the total β-γ coincidence energy spectrum of the system.

[0058] Activity concentration analysis process: The host computer software automatically analyzes the total β-γ coincidence energy spectrum of the system and identifies the characteristic energy peaks of the target xenon isotope (e.g., 133 The 81 keV γ-ray peak of Xe, 131m The activity concentration of the target xenon isotope in the sample gas can be accurately calculated by calculating the net count rate of the region corresponding to the characteristic energy peak, combined with the pre-calibrated system coincidence detection efficiency, the emission branching ratio of the characteristic ray, and the precise cavity volume of the PIPS gas detection chamber 110.

[0059] Mode 2: β Measurement Mode (Applicable to Krypton-85) 85 Kr) monitoring) When the user switches to "Kr monitoring mode" through the host computer software interface, the system control software immediately sends a control command to the electronics system to shut down the high-voltage power supply of the two CZT detectors, causing them to stop working. At the same time, it keeps the high-voltage power supply of the two PIPS detectors normal and activates only the two data acquisition channels corresponding to the two PIPS detectors, ensuring that the system only collects and processes the signals from the PIPS detectors.

[0060] At this time, the data acquisition unit 200 only receives and processes the detection signals from the two PIPS detectors. Because... 85 Kr primarily emits beta particles. The system directly accumulates the beta particle energy signals output by the two PIPS detectors to form a continuous beta particle energy spectrum (the maximum energy of this beta spectrum is approximately 687 keV). In this mode, the system does not perform any logical processing and focuses solely on recording the energy and count information of beta particle events.

[0061] Activity concentration analysis process: The host computer software performs targeted analysis on the acquired β energy spectrum. First, a reasonable energy threshold is set to subtract noise interference at the lower end of the energy spectrum. Then, the β energy spectrum is integrated within a preset region of interest (ROI) to obtain the net count rate of β particles. The calculation... 85 The key parameter for Kr activity concentration is the PIPS gas detection chamber 110 pairs. 85 The total absolute detection efficiency ε_β of Kr β particles can be experimentally calibrated (using known activity). 85 The Kr standard gas source or Monte Carlo simulation method is used to accurately obtain the β-particle count rate, the total absolute detection efficiency ε_β, the actual measurement time, and the volume of the PIPS gas detection chamber 110. Finally, the concentration of β-particles in the sample gas is accurately calculated based on the net β-particle count rate, the total absolute detection efficiency ε_β, the actual measurement time, and the volume of the PIPS gas detection chamber 110. 85 The activity concentration of Kr.

[0062] Please see Figure 1 The measurement system of the present invention also includes a housing 500, in which all hardware structures except the host computer and power supply unit are fixedly installed. The shape and volume of the housing 500 can be flexibly selected based on actual installation requirements, and the present invention does not limit this; its material can be a material conventionally used in shielding bodies in the art, which can meet the shielding and installation strength requirements of the measurement system.

[0063] The side wall of the housing 500 is provided with an air inlet 510 and an air outlet 520. The air inlet 510 is connected to the air inlet pipe 114 on the PIPS gas detection chamber 110 through an air inlet solenoid valve 511, and the air outlet 520 is connected to the air outlet pipe 115 on the PIPS gas detection chamber 110 through an air outlet solenoid valve 521. The air inlet solenoid valve 511 and the air outlet solenoid valve 521 are respectively connected to the host computer for communication, and the host computer controls their on / off state to achieve precise control of the gas passage.

[0064] The side wall of the enclosure 500 is also equipped with a switch 530, a power input interface 540, a USB interface 550, and a network port 560: the switch 530 is used to control the start and stop of the entire measurement system; the power supply unit provides working power to various components of the measurement system through the power input interface 540; the host computer realizes data interaction and control signal transmission with various hardware structures inside the enclosure through the USB interface 550 or the network port 560, ensuring the normal operation of the measurement system.

[0065] The dual-mode inert gas radionuclide measurement system provided by this invention, through coordinated hardware and software control, enables the same hardware system to have two flexibly switchable operating modes: In the "β-γ coincidence measurement mode," the PIPS detector and the CZT detector are simultaneously activated, utilizing their synergistic effect to achieve high-sensitivity coincidence measurement of xenon isotopes, ensuring detection accuracy; in the "β measurement mode," the high-voltage power supply to the CZT detector is automatically shut off, and only the PIPS detector is activated and used as a β spectrometer, specifically for the pure β-decay nuclide krypton-85 (… 85 The invention provides accurate measurement of Kr. Its core advantage lies in integrating two measurement functions that previously required separate devices into a single hardware platform. This effectively solves the problems of high purchase costs, cumbersome operation procedures, and large space occupation caused by separate devices in existing technologies. It truly achieves an integrated design of "one machine, two functions," significantly improving the efficiency of inert gas monitoring and equipment utilization, and adapting to monitoring needs in multiple scenarios.

[0066] Please see Figure 9 The present invention also provides a measurement method based on a dual-mode inert gas radionuclide measurement system, the measurement method comprising the following steps: S1. Receive mode selection instruction and determine whether the working mode is the first working mode or the second working mode; S2. Control the configuration of the power supply unit and data acquisition unit according to the selected working mode; S3. Perform sample measurement and process the collected data according to the data analysis method corresponding to the selected working mode to obtain the activity concentration of the target nuclide.

[0067] The first operating mode in step S1 is the β-γ coincidence measurement mode, also known as the xenon monitoring mode; the second operating mode is the β measurement mode, also known as the krypton monitoring mode.

[0068] Before performing step S1, the entire measurement system is placed in a low-background measurement chamber to reduce the interference of ambient radiation background on the measurement results and ensure measurement accuracy. Then, the operator selects the corresponding working mode (xenon monitoring mode or krypton monitoring mode) based on the sample type (xenon sample or krypton sample) through the host computer software interface. The xenon monitoring mode corresponds to the first working mode (β-γ coincidence measurement mode) and is used to detect radioactive xenon isotopes; the krypton monitoring mode corresponds to the second working mode (β measurement mode) and is used to detect pure β-decay nuclide krypton-85 (…). 85 Kr) Step S2 involves system hardware configuration. Based on the operating mode selected in step S1, the host computer software automatically sends control commands to the power supply unit and data acquisition unit 200 to complete the corresponding hardware configuration. The specific configuration is as follows: In xenon monitoring mode, the control power supply unit applies the corresponding operating high voltage to both PIPS detectors and both CZT detectors (preferably +70V for PIPS detectors and approximately 900V for CZT detectors); initializes the four independent acquisition channels of the data acquisition unit 200, making them all active, and loads the preset parameters of the conformal measurement and analysis algorithm to prepare for subsequent conformal data acquisition and analysis.

[0069] In krypton monitoring mode, the control power supply unit sends a command to the high-voltage module to shut down the high-voltage output of the two CZT detectors, causing them to stop working; at the same time, the high-voltage power supply of the two PIPS detectors is kept normal (preferably +70V); the data acquisition unit 200 is reconfigured to enable only the acquisition channels 1 and 2 corresponding to the two PIPS detectors, and the host computer interface is simultaneously switched to the β energy spectrum display and analysis interface.

[0070] After the hardware configuration is complete, a background measurement of the measurement system needs to be performed using background gas to provide data support for background subtraction in subsequent sample measurements. The specific background measurement procedure is as follows: (1) Background measurement in xenon monitoring mode: The PIPS-BOX chamber is evacuated to a vacuum state through the gas path control system, and then filled with high-purity nitrogen to atmospheric pressure; the measurement program is started, and background data is continuously collected for at least 24 hours. The host computer software synchronously records the individual energy spectrum and coincidence energy spectrum count rate of each detector in the background mode and stores them in the designated database for background subtraction of subsequent sample measurement data.

[0071] (2) Background measurement under krypton monitoring mode: fill the PIPS-BOX chamber with high-purity nitrogen to atmospheric pressure, start the measurement program, obtain the β background energy spectrum of the two PIPS detectors, focus on recording the background count rate in the preset region of interest (ROI, such as 150 keV~700 keV), and complete the acquisition and storage of background data.

[0072] Next, step S3 is performed: sample measurement and data processing to obtain the activity concentration of the target nuclide.

[0073] Please see Figure 10 Sample measurement and analysis in xenon monitoring mode (β-γ coincidence measurement mode): (1) Sample preparation and injection: Using an on-site atmospheric sampling and xenon enrichment device, prepare approximately 50 mL of enriched xenon sample; use the host computer software to control the gas path and control system to transfer a quantitative (e.g., 5 mL) enriched xenon sample into the PIPS-BOX chamber, and then close the inlet and outlet valves of the chamber to seal the sample in the chamber and ensure no gas leakage during the measurement process.

[0074] (2) Data acquisition: Start the sample measurement program, and the host computer software synchronously controls the data acquisition unit 200 to record the list mode data of all four detectors (two PIPS detectors and two CZT detectors). At the same time, the coincidence analysis algorithm runs in real time in the background. To ensure the accuracy of data statistics, the measurement process lasts for 12 hours.

[0075] (3) Data analysis and activity calculation: After the measurement is completed, the host computer software automatically calls the coincidence analysis module to process the collected list mode data; the algorithm first searches for detection events near 81 keV (¹³³Xe characteristic γ-ray) recorded by the CZT detector, and within the preset 2 μs coincidence time window, it searches whether there are accompanying β-particle events in the two PIPS detectors, and statistically obtains the coincidence event count of the 81 keV characteristic peak; then, it extracts the net count rate of the 81 keV peak from the coincidence energy spectrum (after deducting the background coincidence count collected in step two).

[0076] The software automatically retrieves key parameters for ¹³³Xe from the built-in nuclide library: an 81 keV γ-ray branching ratio of 37%, and the system's coincidence detection efficiency for ¹³³Xe (pre-calibrated using a ¹³³Xe standard gas source, with an exemplary value of 0.1%). The operator inputs the actual chamber volume of the PIPS-BOX (an exemplary value of 10.6 mL) and the measurement activity time (12 h). The software automatically calculates and displays the activity concentration of ¹³³Xe in the sample according to a preset formula, with units selectable as Bq / mL (Xe) or Bq / m³ (air).

[0077] Please see Figure 10 Sample measurement and analysis in krypton monitoring mode (β measurement mode) (1) Sample injection: Inject the enriched krypton sample (about 10 mL) into the PIPS-BOX chamber through the gas path control system, close the inlet and outlet gas valves, and ensure the sample is sealed.

[0078] (2) β data acquisition: Start the sample measurement program. The system records the detection signals of the two PIPS detectors and accumulates them to form a continuous β energy spectrum. In order to obtain sufficient statistics and ensure the accuracy of the measurement results, the measurement process lasts for 24 hours.

[0079] (3) Data analysis and activity calculation: After the measurement is completed, the host computer software calls the β analysis module to first perform energy calibration on the β energy spectrum of the two PIPS detectors (optional). 90 Sr / 90 (The Y-type β source was calibrated). Then, the analysis energy range was set to 150 keV~700 keV, and the β energy spectrum within this range was integrated to obtain the total count. Subtracting the background count collected in step two within the corresponding measurement time, the result was obtained. 85Net count of Kr.

[0080] Operator inputs key parameters: PIPS-BOX chamber alignment 85 The total absolute detection efficiency ε_β of Kr β particles (this efficiency needs to be determined before system use by injecting particles of known activity) 85 The Kr standard gas was used for experimental calibration, with exemplary calibration results including ε_β = 0.35, chamber volume (10.6 mL), and measurement activity time (24 h). The software automatically calculated and displayed the activity concentration in the sample according to the formula "Activity Concentration = Net Count / (ε_β × Measurement Time × Chamber Volume)". 85 The activity concentration of Kr.

[0081] Furthermore, to ensure the detection accuracy and stability of the measurement system, rigorous experimental calibration of the system's core parameters is required during implementation. The calibration results must be stored in the host computer software database as the core basis for subsequent sample measurements and activity calculations. The specific calibration content and process are as follows: 1. Meets detection efficiency standards: For each target, the xenon isotopes of interest (including ¹³³Xe, ¹³¹...) m Xe、¹³³ m For Xe, a standard gas source with known activity must be selected, and the measurement experiment must be carried out strictly in accordance with the complete procedure of "β-γ coincidence measurement mode (xenon monitoring mode)" mentioned above. The coincidence detection efficiency of the system for the specific characteristic rays of the nuclide is obtained by back-calculating the net count rate and the known activity, so as to ensure the accuracy of the xenon isotope activity calculation.

[0082] 2. PIPS-BOX 85 Kr's total absolute detection efficiency ε_β calibration: This parameter is for precise measurement. 85 The core of Kr activity concentration must be selected from materials calibrated by the National Institute of Metrology with accurate and reliable activity. 85 The Kr standard gas source was measured according to the operating procedure described in the "β Measurement Mode (Krypton Monitoring Mode)" section above. ε_β was calculated by back-calculating the net count rate obtained from the measurement with the known activity of the standard gas source. It should be noted that the value of ε_β is closely related to factors such as the geometry of the PIPS-BOX cavity, the gas pressure inside the cavity, and the performance of the PIPS detector; therefore, it needs to be recalibrated periodically to ensure its effectiveness.

[0083] 3. Energy Calibration and Resolution Verification: To ensure the accuracy of the detector's energy response, the energy calibration and resolution of both the CZT and PIPS detectors must be checked periodically. The CZT detector uses... 133 Ba (81 keV, 356 keV, etc.), 137Calibration was performed using standard gamma sources such as Cs (662 keV), with a focus on energy calibration and energy resolution checking; the PIPS detector employed... 90 Sr / 90 The β-spectral response characteristics of standard β sources such as Y were verified to ensure the accuracy of β-particle energy detection. 85 Kr's net count calculation provides assurance.

[0084] The dual-mode inert gas radionuclide measurement system provided by this invention integrates a PIPS detector and a CZT detector coincidence detection architecture on a single hardware platform. Through reconfigurable electronics design, it achieves intelligent switching between a "β-γ coincidence measurement mode" and a "pure β measurement mode." The β-γ coincidence measurement mode is used for precise detection of various radioactive xenon isotopes, while the pure β measurement mode, by shutting down the CZT detector and activating only the PIPS detector, transforms the system into a dedicated krypton-85 β spectrometer. This completely solves the drawback of requiring two independent devices in traditional technologies, significantly reducing the overall construction cost, footprint, and maintenance complexity of the monitoring system, and improving equipment utilization. Therefore, this invention effectively overcomes some practical problems in existing technologies, thus possessing high utilization value and practical significance.

[0085] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A dual-mode inert gas radionuclide measurement system, characterized in that, include: The probe includes a PIPS gas detection chamber and a cadmium zinc telluride detector array, wherein the cadmium zinc telluride detector array is located outside the PIPS gas detection chamber and its detection surface is opposite to the gas sample inside the PIPS gas detection chamber. The power supply unit is electrically connected to the PIPS gas detection chamber and the cadmium zinc telluride detector array, respectively, and is used to supply power to the PIPS gas detection chamber and / or the cadmium zinc telluride detector array. The data acquisition unit is communicatively connected to the PIPS gas detection chamber and the cadmium zinc telluride detector array, respectively, and is used to acquire and process detector signals. A host computer is communicatively connected to the data acquisition unit. The host computer is used to analyze the data processed by the data acquisition unit and control the operation of the probe and the data acquisition unit. The dual-mode inert gas radionuclide measurement system can switch between a first operating mode and a second operating mode: In the first working mode, the power supply unit simultaneously supplies power to the PIPS gas detection chamber and the cadmium zinc telluride detector array, the data acquisition unit synchronously acquires signals from the PIPS gas detection chamber and the cadmium zinc telluride detector array, and the host computer completes data analysis based on the time conformity relationship between the two types of signals. In the second operating mode, the power supply unit supplies power to the PIPS gas detection chamber, the data acquisition unit acquires the signal output by the PIPS gas detection chamber, and the host computer performs data analysis based on the β energy spectrum of the PIPS gas detection chamber.

2. The dual-mode inert gas radionuclide measurement system according to claim 1, characterized in that, The PIPS gas detection chamber includes a housing, a first PIPS detector, and a second PIPS detector. The housing includes an aluminum alloy support frame and a carbon fiber plate fixed on the aluminum alloy support frame. The first PIPS detector and the second PIPS detector are mounted opposite each other on the inner wall of the carbon fiber plate, forming a sealed sample gas chamber between the first PIPS detector and the second PIPS detector.

3. The dual-mode inert gas radionuclide measurement system according to claim 2, characterized in that, The tellurium zinc cadmium detector array includes at least a first tellurium zinc cadmium detector and a second tellurium zinc cadmium detector, which are respectively installed in the outer central region of the two carbon fiber plates.

4. The dual-mode inert gas radionuclide measurement system according to claim 1, characterized in that, The data acquisition unit is a digital pulse analyzer based on a field-programmable gate array (FPGA). The FPGA-based FPGA digital pulse analyzer has at least four independent acquisition channels, each of which acquires a detector signal. The FPGA-based FPGA digital pulse analyzer records the channel number, energy, and timestamp information of each detection event in a list mode.

5. The dual-mode inert gas radionuclide measurement system according to claim 1, characterized in that, The host computer includes a dual-mode analysis algorithm library, which includes a coincidence spectrum analysis algorithm for the first working mode and a β spectrum analysis algorithm for the second working mode.

6. The dual-mode inert gas radionuclide measurement system according to claim 1, characterized in that, Also includes: A shielding body surrounds the probe, and the shielding body comprises, from the outside to the inside, a lead layer, a cadmium layer, and a copper layer; The gas path control unit is connected to the PIPS gas detection chamber. The gas path control unit is used to control the injection and discharge of gas samples and is connected to the host computer.

7. A measurement method based on the dual-mode inert gas radionuclide measurement system according to any one of claims 1 to 6, characterized in that, Includes the following steps: Receive mode selection command and determine whether the working mode is the first working mode or the second working mode; The configuration of the power supply unit and data acquisition unit is controlled according to the selected operating mode; Perform sample measurements and process the collected data according to the data analysis method corresponding to the selected working mode to obtain the activity concentration of the target nuclide.

8. The measurement method according to claim 7, characterized in that, When the working mode is the first working mode, the data analysis method includes: Acquire list pattern data from the PIPS gas detection chamber and the cadmium zinc telluride detector array; Based on a preset coincidence time window, coincidence correlation is performed on γ / X-ray events from the cadmium zinc telluride detector and β events from the PIPS gas detection chamber to generate coincidence energy spectra. Analyze the characteristic peaks in the coincidence spectrum to calculate the activity concentration of the radioactive xenon isotope.

9. The measurement method according to claim 7, characterized in that, When the working mode is the second working mode, the data analysis method includes: Acquire β-spectral data from the PIPS gas detection chamber; The net count rate is obtained by integrating the β energy spectrum within a set energy range. The activity concentration of radioactive krypton-85 was calculated based on the total detection efficiency of the PIPS gas detection chamber for the target β nuclide.

10. The measurement method according to claim 7, characterized in that, Before the step of performing sample measurement, the method further includes a step of using background gas to perform background measurement on the measurement system; when calculating the activity concentration, the corresponding background count is subtracted.

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