An arrayed alpha spectrometry system

Abstract

The application discloses an array type alpha energy spectrum measurement system, which adopts large-flow air sampling (exhaust capacity can reach 500-1000 m 3 / h), can enrich radioactive aerosols with ultra-low concentration, and can improve the lower limit of detection of measurement from the order of magnitude of 10 ‑1 Bq / m 3 to 10 ‑3 Bq / m 3 , and expands the low-range range of measurement. The sampling area of the filter paper is not less than 6500 mm 2 . Compared with a traditional single-channel sampling and measurement method, the system can more uniformly enrich the aerosols with the same sampling volume to the large-area sampling filter paper, ensures that the enrichment of the aerosols with ultra-high concentration does not exceed the effective enrichment thickness, and thus influences the measurement precision of the high-concentration aerosols. The upper limit of the measurement range is improved from the order of magnitude of 10 3 Bq / m 3 to the order of magnitude of 10 5 Bq / m 3 .

Description

Technical Field

[0001] This invention relates to the field of methods for measuring the radioactivity of aerosols in the air, and in particular to an array-type alpha spectrum measurement system for measuring the radioactivity activity of low-concentration, extremely low-concentration, and ultra-high-concentration radioactive aerosols in the environment. Background Technology

[0002] Aerosol radioactivity measurement is a primary method for environmental radioactivity monitoring. Following the 2011 Fukushima incident in Japan, environmental monitoring departments strongly recognized the importance of measuring low-concentration aerosols in the environment to protect the safety of the nuclear environment and the health of workers and the public. Currently, similar commercial aerosol monitoring equipment internationally typically has a detection limit of 0.1-0.2 Bq / m³. 3 However, our monitoring capabilities for the spread of nuclear pollution in the atmosphere of neighboring countries are still insufficient.

[0003] Current measurement techniques primarily rely on single-channel measurements. The most practical approach is to use filter paper to concentrate the alpha radioactivity. The sampled filter paper is then moved below the detector, and the alpha radioactivity activity on the filter paper is measured to further estimate the total alpha radioactivity activity in the sampled air.

[0004] Existing technologies have two main drawbacks:

[0005] 1. The detection range can only reach 10. -1 Bq / m 3 Due to limitations in the measurement area and sampling flow rate of single-channel detectors, it is impossible to quickly measure the radioactivity activity of low-concentration or extremely low-concentration radioactive aerosols.

[0006] 2. The upper limit of the measurement range is limited. Under current technological conditions, the upper limit of the detection range of equipment is 10... 3 Bq / m 3 On the order of magnitude. In environments with very high concentrations of radioactive aerosols (radioactive aerosol concentrations up to ~10⁻⁶), the concentration can reach [a certain value]. 5 Bq / m 3 Using a single-channel sampling and measurement method, due to the limited filtration area of ​​the filter paper, aerosols in the air quickly accumulate on the filter paper collection surface, resulting in over-enrichment. This leads to a thicker aerosol cover and increased measurement error. When the mass thickness of the radioactive surface cover exceeds 10 micrometers of water, the probe will be unable to detect radioactive particles generated by the bottom aerosols, thus failing to meet the requirements for accurate measurement of high concentrations of total alpha activity.

[0007] Therefore, how to provide an array-type alpha spectrum measurement system that can meet the requirements for measuring the radioactivity of low or extremely low concentrations of radioactive aerosols in the environment is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] In view of the above problems, the present invention provides an array-type alpha spectrum measurement system to overcome or at least partially solve the above problems. It can meet the requirements for measuring the radioactivity of low or extremely low concentrations of radioactive aerosols in the environment, and can broaden the measurement range of total aerosol alpha activity to 10. -3 Bq / m 3 ~10 5 Bq / m 3 It offers a wide measurement range spanning eight orders of magnitude to meet the monitoring needs of environmental pollution monitoring under any circumstances.

[0009] This invention provides the following solution:

[0010] An array-type alpha spectrum measurement system, comprising:

[0011] An enrichment unit is used to enrich radioactive aerosols in the sampled gas onto the sampling filter paper.

[0012] An array-type aerosol measurement unit is used to receive the sampling filter paper and detect different regions of the sampling filter paper through a multi-channel detection component to obtain multiple independent α energy spectra;

[0013] The analysis unit is used to synthesize the received multiple independent α energy spectra to obtain a total α energy spectrum, and to analyze and calculate the total α energy spectrum to obtain the total activity of radioactive aerosol α.

[0014] Preferably, the enrichment unit includes an air sampling component for guiding the sampled gas onto the sampling filter paper.

[0015] Preferably, the air sampling assembly includes a vacuum pump and a pump control module, the pump control module being connected to the analysis unit.

[0016] Preferably, the vacuum pump has a pumping capacity of 500-1000 cubic meters per hour.

[0017] Preferably, the area of ​​the sampling filter paper is not less than 6500 square millimeters.

[0018] Preferably, the detection assembly includes a connected PIPS detector and a digital multichannel analyzer.

[0019] Preferably, the effective measurement area of ​​the PIPS detector is not less than 475 square millimeters.

[0020] Preferably, the detection component includes 15 channels, and the total effective measurement area of ​​the 15 channels is not less than 7000 square millimeters.

[0021] Preferably, the digital multichannel analyzer can be communicatively connected to the analysis unit via a data communication module.

[0022] Preferably, the system further includes an automatic sample delivery unit, which is used to deliver the sampling filter paper to the array-type aerosol measurement unit.

[0023] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0024] The array-type alpha spectrum measurement system provided in this application embodiment utilizes high-flow-rate air sampling (air extraction volume can reach 500-1000m³). 3 / h), which can enrich ultra-low concentrations of radioactive aerosols, and can reduce the detection limit of measurement from 10 -1 Bq / m 3 The magnitude increased to 10 -3 Bq / m 3 This expands the low-range measurement capability.

[0025] In addition, in the preferred embodiment, the sampling area of ​​the filter paper is not less than 6500 mm². 2 Compared to traditional single-channel sampling and measurement methods, this system can more uniformly enrich aerosols of the same sampling volume onto a large-area sampling filter paper, ensuring that the enrichment of aerosols at ultra-high concentrations does not exceed its effective enrichment thickness, thus affecting the measurement accuracy of high-concentration aerosols. The upper limit of the measurement range is increased from 10... 3 Bq / m 3 The order of magnitude increased to 10 5 Bq / m 3 The order of magnitude.

[0026] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0028] Figure 1 This is a connection block diagram of an array-type alpha spectrum measurement system provided in an embodiment of the present invention.

[0029] In the figure: Enrichment unit 1, vacuum pump 11, pump control module 12, sampling filter paper 2, array aerosol measurement unit 3, PIPS detector 31, digital multichannel analyzer 32, analysis unit 4, data communication module 5. Detailed Implementation

[0030] 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 a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0031] See Figure 1 This invention provides an array-type α-energy spectroscopy measurement system, such as... Figure 1 As shown, the system may include:

[0032] Enrichment unit 1, which is used to enrich radioactive aerosols in the sampled gas onto the sampling filter paper 2;

[0033] An array-type aerosol measurement unit 3 is used to receive the sampling filter paper 2 and detect different areas of the sampling filter paper through a multi-channel detection component to obtain multiple independent α energy spectra;

[0034] Analysis unit 4 is used to synthesize the received multiple independent α energy spectra to obtain a total α energy spectrum, and to analyze and calculate the total α energy spectrum to obtain the total activity of radioactive aerosol α.

[0035] The array-type alpha spectrum measurement system provided in this application uses an enrichment unit to enrich radioactive aerosols in the sampled gas onto a sampling filter paper. This filter paper can be made of a larger enrichment area, enabling the enrichment of ultra-low concentrations of radioactive aerosols. The sampling filter paper is then transferred to the array-type aerosol measurement unit, which includes a multi-channel detection component capable of detecting different areas on the sampling filter paper. Each detection component obtains an independent alpha spectrum. The analysis unit combines these independent alpha spectra into a total alpha spectrum through energy alignment, and finally calculates the total aerosol alpha activity. The analysis unit generates and outputs a measurement report based on the analysis results, completing the measurement.

[0036] In order to ensure a good enrichment effect, the embodiment of this application can provide that the enrichment unit includes an air sampling component, which is used to guide the sampled gas onto the sampling filter paper.

[0037] Furthermore, the air sampling assembly includes a vacuum pump 11 and a pump control module 12, the pump control module 12 being connected to the analysis unit 4. The vacuum pump has a pumping capacity of 500-1000 cubic meters per hour. This is due to the use of high-flow-rate air sampling (pumping capacity up to 500-1000 cubic meters per hour). 3 / h), which can enrich ultra-low concentrations of radioactive aerosols, and can reduce the detection limit of measurement from 10 -1 Bq / m 3 The magnitude increased to 10 -3 Bq / m 3 This expands the low-range measurement capability.

[0038] To further ensure good enrichment and detection effects, this embodiment of the application may also provide that the area of ​​the sampling filter paper is not less than 6500 square millimeters. The detection component includes a connected PIPS detector 31 and a digital multichannel analyzer 32. The effective measurement area of ​​the PIPS detector 31 is not less than 475 square millimeters. The detection component includes 15 channels, and the total effective measurement area of ​​the 15 channels is not less than 7000 square millimeters.

[0039] Working principle of array-type aerosol measurement unit:

[0040] PIPS (Ion Implanted Passivated Silicon Semiconductor Detector) is a PN junction semiconductor detector formed by ion doping. Its sensitive region is very thin, it is insensitive to gamma rays, and it outputs a fast pulse signal with high energy resolution, making it ideal for measuring alpha radioactivity. Based on the efficient energy spectrum measurement capability of PIPS semiconductor detectors, the energy spectrum of radioactive aerosol samples can be measured in real time. Using specialized spectral analysis algorithms, interference from natural radioactivity can be removed, thus obtaining highly accurate artificial radioactive aerosol concentrations.

[0041] Charged particles (alpha particles) enter the sensitive region of the detector, depleting their energy and generating electron-hole pairs through electron transitions from the valence band to the conduction band. The electric field within the depletion layer separates the free positively charged particles and collects them onto the electrodes. When the particle energy is completely absorbed by the depletion layer, the output signal amplitude is proportional to the energy of the incident particle.

[0042] PIPS detectors are typically packaged together with a preamplifier. The output signal, amplified by the preamplifier, can be transmitted over longer distances before entering a multichannel pulse amplitude analyzer. The function of the multichannel pulse amplitude analyzer is to convert the measured analog signal into a digital quantity that a computer can recognize, thus distinguishing the pulse amplitude. Its working principle is as follows: analog signals of different amplitudes are converted into corresponding digital signals, each representing a channel address. This channel address is used as the address code in a memory to record the number of pulses. Counting each channel address reveals the distribution of pulses. Since pulse amplitude represents different manifestations of the radiated energy of various elements, the distribution of the radiated energy of each element can be obtained.

[0043] Because alpha particles have weak penetrating power in air, the detector and the sample being measured need to be placed in a vacuum environment to ensure the accuracy of the measurement.

[0044] The energy spectrum data acquired by the multichannel pulse amplitude analyzer is transmitted to the host computer software. Through the dedicated spectral analysis algorithm built into the analysis software, the total α, activity, and corresponding activity of the target nuclide of the sample can be calculated.

[0045] To facilitate connection between the digital multichannel analyzer and the analysis unit, embodiments of this application may also provide that the digital multichannel analyzer can be communicatively connected to the analysis unit 4 via a data communication module 5. The analysis unit provided in these embodiments may include any necessary hardware devices and corresponding software.

[0046] To facilitate the delivery of the sampling filter paper to the array-type aerosol measurement unit after the aerosol enrichment unit has completed the enrichment of aerosols, embodiments of this application may also provide an automatic sample delivery unit, which is used to deliver the sampling filter paper to the array-type aerosol measurement unit.

[0047] The array-type alpha spectrum measurement system provided in this application embodiment may include the following steps when in use.

[0048] 1. Uses an air sampling unit (sampling capacity up to 500-1000m³). 3 / h) Radioactive aerosol enrichment is carried out, and the aerosols will be enriched in an area of ​​not less than 6500 mm². 2 On the sampling filter paper;

[0049] 2. The collected aerosol filter paper is transferred to the array-type aerosol measurement unit through an automated device;

[0050] 3. The array-type aerosol measurement unit uses a 15-channel PIPS detector array for measurement, with an effective measurement area of ​​no less than 475 mm² for each PIPS detector. 2 The total effective measuring area of ​​the device is not less than 7000 mm².2 ;

[0051] 4.15 PIPS detectors were used to perform alpha spectrum measurements to obtain independent alpha spectra;

[0052] 5. The 15 alpha spectra were combined into a total alpha spectrum by energy alignment.

[0053] 6. Analyze the total α energy spectrum and calculate the total α activity of aerosols;

[0054] 7. Generate a measurement report from the analysis results and output it to complete the measurement.

[0055] In summary, the array-type alpha spectrum measurement system provided in this application utilizes high-flow-rate air sampling (pumping volume can reach 500-1000 m³ / s). 3 / h), which can enrich ultra-low concentrations of radioactive aerosols, and can reduce the detection limit of measurement from 10 -1 Bq / m 3 The magnitude increased to 10 -3 Bq / m 3 This expands the low-range measurement capability. The filter paper sampling area should be no less than 6500 mm². 2 Compared to traditional single-channel sampling and measurement methods, this system can more uniformly enrich aerosols of the same sampling volume onto a large-area sampling filter paper, ensuring that the enrichment of aerosols at ultra-high concentrations does not exceed its effective enrichment thickness, thus affecting the measurement accuracy of high-concentration aerosols. The upper limit of the measurement range is increased from 10... 3 Bq / m 3 The order of magnitude increased to 10 5 Bq / m 3 The order of magnitude.

[0056] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0058] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. An array-type α-energy spectroscopy measurement system, characterized in that, include: An enrichment unit is included to enrich radioactive aerosols in the sampled gas onto sampling filter paper. The enrichment unit includes an air sampling component for guiding the sampled gas onto the sampling filter paper. The air sampling component includes a vacuum pump and a pump control module, the pump control module being connected to the analysis unit. The vacuum pump has a pumping capacity of 500-1000 cubic meters per hour. The sampling filter paper has an area of ​​not less than 6500 square millimeters. An array-type aerosol measurement unit is used to receive the sampling filter paper and detect different regions of the sampling filter paper through a multi-channel detection component to obtain multiple independent α energy spectra; The analysis unit is used to synthesize the received multiple independent α energy spectra to obtain a total α energy spectrum, and to analyze and calculate the total α energy spectrum to obtain the total activity of radioactive aerosol α.

2. The array-type α-energy spectroscopy measurement system according to claim 1, characterized in that, The detection components include a connected PIPS detector and a digital multichannel analyzer.

3. The array-type α-energy spectroscopy measurement system according to claim 2, characterized in that, The effective measurement area of ​​the PIPS detector is not less than 475 square millimeters.

4. The array-type α-energy spectroscopy measurement system according to claim 3, characterized in that, The detection component includes 15 channels, and the total effective measurement area of ​​the 15 channels is not less than 7000 square millimeters.

5. The array-type α-energy spectroscopy measurement system according to claim 2, characterized in that, The digital multichannel analyzer can communicate with the analysis unit via a data communication module.

6. The array-type α-energy spectroscopy measurement system according to claim 1, characterized in that, It also includes an automatic sample delivery unit, which is used to deliver the sampling filter paper to the array-type aerosol measurement unit.

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