CN117607938A - Online monitoring device and online monitoring method for atmospheric aerosol radioactivity - Google Patents

Abstract

The invention discloses an online monitoring device and an online monitoring method for atmospheric aerosol radioactivity, wherein the online monitoring device comprises an acquisition module, a measurement module and an automatic control module; the measuring module comprises a detecting unit, a shielding unit and a data processing unit, wherein the detecting unit is positioned in the shielding unit and is connected with the data processing unit; the collecting module is arranged in front of the measuring module, the collecting module comprises a sampling unit and a paper feeding unit, the sampling unit comprises a sampling container, the paper feeding unit comprises filter paper and a driving motor for driving the filter paper to move, and the filter paper sequentially penetrates through the sampling container and the shielding unit to move; the signal output end of the automatic control module is respectively connected with the signal input ends of the acquisition module and the measurement module; the on-line monitoring method comprises sampling and measuring. According to the invention, the automatic control module, the acquisition module and the measurement module work cooperatively, and the shielding unit can reduce the influence of environmental background on detection, so that the accuracy of radioactivity monitoring is improved.

Description

An online monitoring device and online monitoring method for atmospheric aerosol radioactivity

Technical field

The invention relates to the technical field of radiation environment monitoring, and in particular to an online monitoring device and online monitoring method for atmospheric aerosol radioactivity.

Background technique

With the development of science and technology, the use of nuclear energy is becoming more and more extensive, releasing large amounts of alpha nuclides, beta nuclides and gamma nuclides into the environment, causing radiation effects on humans through external and internal irradiation, so radioactive gases The monitoring of sol has become an important part of routine radiation environment monitoring and nuclear emergency monitoring. Total α, total β and γ nuclides in the environment are divided into natural radionuclides and artificial radionuclides. Among them, natural radionuclides mainly originate from 222 Rn and ²²⁰ Rn and ²²⁰ Rn released by the decay of ground radionuclides ²³⁸ U and ²³² Th. Its decay daughter, and the α nuclides, β nuclides and γ nuclides produced by the decay of artificial radionuclides are the objects of environmental monitoring. Their activity concentrations are usually very low, and the interference of natural nuclides needs to be deducted during monitoring.

Existing radioactive aerosol monitoring devices and instruments have problems such as sampling flow, small sampling volume, poor reliability, and low integration. At the same time, due to defects in design principles or algorithms, many radioactive aerosol monitoring devices have low sensitivity to natural radioactive aerosol radon. Thorium, its decay products and γ rays cannot be accurately measured and eliminated. During use, inaccurate measurement results or false alarms caused by natural radioactive interference often occur, which seriously affects the normal use of the equipment and greatly weakens its accurate measurement capabilities. The current common monitoring method for nuclear power plants is to use a large-flow sampler to sample aerosols and then send them back to the laboratory for analysis. This method is time-consuming and labor-intensive, and cannot detect abnormal leaks and accidental releases of nuclear facilities in a timely manner.

Contents of the invention

The technical problem to be solved by the present invention is to provide an online monitoring device and online monitoring method for atmospheric aerosol radioactivity.

The technical solution adopted by the present invention to solve its technical problems is: an online monitoring device for atmospheric aerosol radioactivity, including a collection module, a measurement module and an automatic control module;

The measurement module includes a detection unit, a shielding unit and a data processing unit. The detection unit is located in the shielding unit, and the detection unit is connected to the data processing unit;

The collection module is located in front of the measurement module. The collection module includes a sampling unit and a paper transport unit. The sampling unit includes a sampling container. The paper transport unit includes filter paper and a drive motor that drives the filter paper to move. The filter paper is moved through the sampling container and the shielding unit in sequence;

The signal output end of the automatic control module is connected to the signal input end of the acquisition module and the measurement module respectively.

Preferably, the shielding unit includes a vacuum chamber and a shielding body located in the vacuum chamber, the filter paper is passed through the vacuum chamber, and the vacuum chamber is provided with a sealing gasket at a position in contact with the filter paper; the shielding body includes a first gasket symmetrically arranged on the front and back of the filter paper. The shielding body and the second shielding body, the first shielding body and the second shielding body are combined to form a detection inner cavity;

The detection unit is located in the detection inner cavity and arranged close to the surface of the filter paper.

Preferably, the detection unit includes a detector and a photomultiplier tube. The detector includes a first detector and a second detector. The first detector receives α-rays, β-rays and γ-rays, and the second detector receives β-rays and γ-rays. , the first detector and the second detector are symmetrically arranged on the front and back of the filter paper; one end of the photomultiplier tube is connected to the detector, and the other end is connected to the data processing unit;

The data processing unit includes a preamplifier, a multi-channel pulse analyzer and a logic circuit, and the output end of the data processing unit is connected to the industrial computer.

Preferably, the paper transport unit also includes a paper feed wheel, a guide roller and a paper take-up wheel. The paper take-up wheel is connected to the drive motor. The paper feed wheel and paper take-up wheel are symmetrically arranged on both sides of the sampling unit and the measurement module. Both ends of the filter paper The filter paper is wound on the paper feed wheel and the paper take-up wheel respectively, and the guide roller is arranged between the paper feed wheel and the paper take-up wheel; the filter paper is sequentially transferred from the paper feed wheel to the guide roller and the paper take-up wheel.

Preferably, the sampling unit further includes a gas channel and a sampling fan, the gas channel is connected to the gas outlet of the sampling container, the sampling fan is connected to the outlet of the gas channel, and the gas channel is also provided with a first pressure sensor and a mass flow meter;

The filter paper moves past the air inlet of the sampling container.

Preferably, the automatic control module includes a main control unit that processes, displays, stores and transmits monitoring data, and an alarm unit that alerts to abnormal monitoring results and equipment failures.

Preferably, the online monitoring device further includes a housing, the acquisition module and the measurement module are both located inside the housing, and the automatic control module is located outside the housing.

An online monitoring method for atmospheric aerosol radioactivity uses the above-mentioned online monitoring device for atmospheric aerosol radioactivity. The online monitoring method includes the following steps:

S1. Sampling: The automatic control module sends a sampling signal. The paper transport unit responds to the sampling signal and sends the filter paper to the sampling unit. The sampling unit deposits the aerosols in the atmosphere on the surface of the filter paper. The automatic control module generates a signal based on the sampling feedback signal output by the sampling unit. Transmission signal, the paper transport unit responds to the transmission signal to transmit the filter paper to the detection unit;

S2. Measurement: The automatic control module generates a detection signal based on the transmission feedback signal output by the paper transport unit. The detection unit detects the filter paper in response to the detection signal. The data processing unit processes the radioactive signal output by the detection unit to obtain the radioactive signal in the atmospheric aerosol. Activity concentrations of artificial alpha nuclides, artificial beta nuclides and gamma nuclides.

Preferably, the detection unit receives the radioactive rays of the aerosol on the filter paper, the data processing unit outputs the signals of α rays, β rays and γ rays, and processes the signals to obtain the natural radon thoron daughter ²¹² Po, ²¹⁴ Po and ²¹⁸ Po nuclides. activity concentration;

Calculate the activity concentrations of natural α nuclides and natural β nuclides produced by natural radon thoron progeny based on the nuclide activity concentration of natural radon thoron progeny, combined with the total α nuclides and total β nuclides in atmospheric aerosols Activity concentration, calculate the activity concentration of artificial α nuclides and artificial β nuclides in atmospheric aerosols; calculate the activity concentration of γ nuclides in atmospheric aerosols.

Preferably, formula (I) is used to calculate the activity concentration A (β) of the natural β nuclide, and formula (II) is used to calculate the activity concentration A (α) of the natural α nuclide. Formula (I) and formula (II) Expressed as follows:

Among them, a, b, and c are the activity factors corresponding to the β energy spectrum of ²¹² Po, ²¹⁴ Po, and ²¹⁸ Po nuclides respectively, are the activity concentrations of ²¹² Po, ²¹⁴ Po, and ²¹⁸ Po nuclides respectively;

Among them, d and e are the activity factors corresponding to the α energy spectrum of ²¹² Po and ²¹⁴ Po nuclides respectively, are the activity concentrations of ²¹² Po and ²¹⁴ Po nuclides respectively.

Beneficial effects of the present invention:

The online monitoring device of the present invention adopts a modular design, and each module works cooperatively to realize real-time online continuous monitoring of atmospheric aerosol radioactivity according to the flow of sampling, measurement, and data processing. By setting the sampling module and the measurement module separately, measurement can be performed while sampling. In addition, all collected gases are filtered through filter paper in the sampling container, and the collected gases are not leaked to avoid contamination of the detection unit. Aerosol radioactivity detection is carried out in a shielded unit, which can reduce the environmental background value and improve the alpha spectrum resolution, thereby effectively identifying the interference of natural radon and thoron daughter bodies. It can also reduce the impact of environmental humidity and improve the ability of the detection unit to adapt to the environment. ability.

The online monitoring method of the present invention sends corresponding signals to the paper transport unit, sampling unit, detection unit and data processing unit through the automatic control module to realize filter paper sampling, filter paper transportation, filter paper radioactive detection and radioactive signal processing, thereby obtaining the content of atmospheric aerosols. Activity concentrations of artificial alpha nuclides, artificial beta nuclides and gamma nuclides.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and examples. In the accompanying drawings:

Figure 1 is a schematic structural diagram of the online monitoring device for atmospheric aerosol radioactivity of the present invention;

The numbers in the drawings are as follows: 1. Collection module; 11. Sampling container; 111. Air inlet; 112. Gas channel; 12. Filter paper; 13. First pressure sensor; 14. Mass flow meter; 15. Sampling fan; 16. Paper feed roller; 17. Take-up roller; 18. Guide roller; 2. Measurement module; 21. Detector; 22. Shield; 23. Vacuum chamber; 231. Vacuum channel; 24. Second pressure sensor; 25 , Vacuum pump; 26. Vacuum conversion head; 3. Automatic control module; 4. Industrial computer.

Detailed ways

In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, what needs to be understood is "front", "back", "up", "down", "left", "right", "vertical", "horizontal", "vertical", "horizontal", The orientations or positional relationships indicated by "top", "bottom", "inner", "outer", "head", "tail", etc. are based on the orientation or positional relationship shown in the drawings and are constructed and operated in specific orientations. It is only for the convenience of describing the present technical solution, and does not indicate that the device or element referred to must have a specific orientation, and therefore cannot be understood as a limitation of the present invention.

It should also be noted that, unless otherwise expressly stipulated and limited, terms such as "installation", "connection", "connection", "fixing" and "setting" should be understood in a broad sense. For example, it can be a fixed connection or a fixed connection. It can be detachably connected or integrated; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements or an interaction between two elements. When an element is referred to as being "on" or "under" another element, it can be "directly" or "indirectly" on the other element or one or more intervening elements may also be present. The terms "first", "second", "third", etc. are only used to facilitate the description of the present technical solution and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of indicated technical features. Therefore, Features defined as "first," "second," "third," etc. may explicitly or implicitly include one or more of these features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

As shown in Figure 1, an online monitoring device for atmospheric aerosol radioactivity in some embodiments of the present invention is used to monitor the changing trend of radioactive aerosols in the atmospheric environment in real time. The online monitoring device includes a collection module 1, a measurement module 2 and an automatic Control module 3. The collection module 1 is used to collect aerosol samples from the atmosphere. The collection method is to pass the air and deposit the aerosols on the filter paper 12 . The measurement module 2 is used to measure the radioactive signal emitted by the aerosol sample on the filter paper 12 and process the radioactive signal to obtain the activity concentrations of total α nuclides, total β nuclides and γ nuclides in the aerosol sample. The automatic control module 3 is used to logically control the acquisition module 1 and the measurement module 2, thereby completing logical functions such as acquisition, measurement, and data processing, and ensuring the automatic and continuous normal operation of the online monitoring device.

The measurement module 2 includes a detection unit, a shielding unit and a data processing unit. The detection unit is located in the shielding unit, and the detection unit is connected to the data processing unit. The shielding unit includes a vacuum chamber 23 and a shielding body 22 located in the vacuum chamber 23. The filter paper 12 is inserted through the vacuum chamber 23. The vacuum chamber 23 is provided with a sealing gasket at a position in contact with the filter paper 12, so that the vacuum chamber 23 can maintain a sealed state during vacuuming, thereby improving the accuracy of aerosol radioactivity detection. The vacuum chamber 23 is connected to the vacuum channel 231. The outlet of the vacuum channel 231 is provided with a vacuum pump 25 connected to the automatic control module 3. The vacuum pump 25 evacuates the vacuum chamber 23, which can reduce the tailing effect of the radioactive aerosol radon thoron daughter during measurement. A second pressure sensor 24 is provided on the vacuum channel 231 for performing a pressure difference test on the vacuum pump 25 corresponding to the vacuum channel 231 to ensure its normal operation. The shielding body 22 includes a first shielding body and a second shielding body symmetrically arranged on the front and back of the filter paper 12. The first shielding body and the second shielding body are combined to form a detection inner cavity, and the detection unit is located in the detection inner cavity of the shielding body 22. Arranged close to the surface of the filter paper 12, the shielding body 22 reduces the environmental background value and reduces the impact of the environmental background on the detection of artificial aerosol radioactivity. In some embodiments, the shielding body 22 is a square body as a whole, with a detection cavity inside. The shielding body 22 can be made of lead material, and its wall thickness is 3-7 cm.

The detection unit includes a detector 21 and a photomultiplier tube. The detector 21 is used to receive radioactive rays emitted by the aerosol on the filter paper 12, and the photomultiplier tube is used for signal enhancement. The detector 21 includes a first detector and a second detector. The first detector receives α rays, β rays and γ rays. The second detector receives β rays and γ rays. The first detector and the second detector are symmetrically arranged. on the front and back of the filter paper 12. In some embodiments, detector 21 is a PIPS detector. The photomultiplier tube is located at the rear end of the detector 21 and is connected to the detector 21 , and the other end of the photomultiplier tube is connected to the data processing unit. It can be understood that the detector 21 and the photomultiplier tube can adopt existing technologies, and will not be described in detail here.

The data processing unit includes a preamplifier, multi-channel pulse analyzer and logic circuits. The detection inner cavity of the shielding body 22 of the detection unit is provided with a vacuum switching head 26 to provide a vacuum environment. The vacuum switching head 26 is connected to the preamplifier and the multi-channel pulse analyzer. In some embodiments, the output end of the data processing unit is connected to an industrial computer 4 as the host computer. The industrial computer 4 is used for program control of the entire device, including the control of the acquisition module 1, the measurement module 2 and the automatic control module 3. At the same time, the industrial computer 4 Machine 4 also completes final data calculation, storage and other functions. It can be understood that the preamplifier, multi-channel pulse analyzer, logic circuit, vacuum switching head 26 and industrial computer 4 can all adopt existing technologies, and will not be described in detail here.

The collection module 1 is located in front of the measurement module 2. The collection module 1 includes a sampling unit and a paper transport unit. The sampling unit includes a sampling container 11. The paper transport unit includes a filter paper 12 and a drive motor (not shown) that drives the filter paper 12 to move. The filter paper 12 moves through the sampling container 11 and the shielding unit in sequence. The filter paper 12 may be made of polypropylene or polyethylene in some embodiments. The movement of the filter paper 12 passes through the air inlet 111 of the sampling container 11. Specifically, the angle α between the moving direction of the filter paper 12 and the air inlet direction of the sampling container 11 is 90°≥α>0°. It can be understood that the filter paper The moving direction of 12 is not parallel to the air inlet direction of the sampling container 11. Furthermore, the angle α between the moving direction of the filter paper 12 and the air inlet direction of the sampling container 11 is preferably 90°, which is conducive to filtering the air through the filter paper 12 so that aerosols in the air are fully deposited on the filter paper 12 .

The sampling unit also includes a gas channel 112 and a sampling fan 15. The gas channel 112 is connected to the air outlet of the sampling container 11. The sampling fan 15 is connected to the outlet of the gas channel 112. The sampling fan 15 is an exhaust fan. The collection module 1 passes through the sampling fan. 15 drives air into the sampling unit, and aerosols in the air are deposited on the surface of the filter paper 12 . The gas channel 112 is also provided with a first pressure sensor 13 and a mass flow meter 14. The first pressure sensor 13 is used to record the pressure difference in the gas channel 112, and the mass flow meter 14 is used to feedback control the gas collection flow and record the air sampling volume. , when the gas sampling flow does not meet the program setting, an alarm will be triggered; when the preset air sampling volume or preset sampling time is reached, the collection module 1 will transfer the filter paper 12 with the aerosol sample collected to the measurement module 2.

The paper transport unit also includes a paper feed wheel 16 , a guide roller 18 and a take-up wheel 17 . The take-up wheel 17 is connected to a drive motor, and the drive motor is electrically connected to the automatic control module 3 . The paper feed wheel 16 and the paper take-up wheel 17 are symmetrically arranged on both sides of the sampling unit and the measurement module 2, and the two ends of the filter paper 12 are wound around the paper feed wheel 16 and the paper take-up wheel 17 respectively. The guide roller 18 is disposed between the paper supply wheel 16 and the paper delivery wheel 17. Multiple guide rollers 18 can be provided. The multiple guide rollers 18 are located on the same horizontal plane. Specifically, they can be disposed in front of the sampling container 11 and behind the vacuum chamber 23. , The guide roller 18 can also be disposed between the sampling container 11 and the vacuum chamber 23 to guide the transmission of the filter paper 12 and tension the filter paper 12 to keep the filter paper 12 straight during the transportation process. The height of the plane where the paper feed roller 16 and the paper take-up roller 17 are located is lower than the height of the plane where the guide roller 18 is located. The guide roller 18 is located on the lower surface side of the filter paper 12 , and the filter paper 12 is close to the guide roller 18 . During the transmission process of the filter paper 12, the automatic control module 3 controls the drive motor to drive the take-up wheel 17 to rotate. The take-up wheel 17 drives the filter paper 12 to be transferred from the paper feed wheel 16 to the guide roller 18 and the take-up wheel 17 in sequence. After the measurement is completed, the aerosol sample is transferred to the take-up wheel 17 along with the filter paper 12 for storage, thereby realizing the continuous and cumulative collection of atmospheric aerosol samples, the storage and collection of aerosol samples, and the subsequent replacement of the filter paper 12.

The signal output end of the automatic control module 3 is connected to the signal input end of the acquisition module 1 and the measurement module 2 respectively. The automatic control module 3 includes a main control unit that processes, displays, stores and transmits monitoring data, and an alarm unit that reports abnormal monitoring results and equipment failures. The alarm unit can automatically alarm abnormal monitoring results when the radioactivity monitoring results exceed the preset alarm threshold. When the sampling fan 15 fails, the gas channel 112 is blocked or leaks, the filter paper 12 is broken or defective, and the detector 21 has no counting signal. Automatically alarm equipment failure when there is a malfunction.

In some embodiments, the online monitoring device further includes a housing, the acquisition module 1 and the measurement module 2 are both located inside the housing, and the automatic control module 3 is located outside the housing. The sampling unit of the collection module 1 also includes an air inlet channel (not shown) inserted in the housing, and the air outlet of the air inlet channel is connected to the air inlet 111 of the sampling container 11 . A seal is provided at the position where the air inlet channel contacts the casing, so that the inside of the casing is in a sealed state.

The present invention also proposes an online monitoring method for atmospheric aerosol radioactivity, which adopts the above-mentioned online monitoring device for atmospheric aerosol radioactivity. The online monitoring method includes the following steps:

S1. Sampling: The automatic control module 3 sends a sampling signal. The paper transport unit responds to the sampling signal and sends the filter paper 12 to the sampling unit. The sampling unit deposits aerosols in the atmosphere on the surface of the filter paper 12. The automatic control module 3 generates a transmission signal according to the sampling feedback signal output by the sampling unit, and the paper transport unit responds to the transmission signal to transmit the filter paper 12 to the detection unit, specifically to the detection inner cavity of the shield 22 .

S2. Measurement: The automatic control module 3 generates a detection signal based on the transmission feedback signal output by the paper transport unit. The detection unit responds to the detection signal and detects the filter paper 12 in the detection inner cavity. The data processing unit processes the radioactive signal output by the detection unit. Specifically, the detection unit receives radioactive rays from the aerosol sample deposited on the filter paper 12. The data processing unit identifies, shapes, amplifies and converts the radioactive signal output by the detection unit and outputs a standard pulse signal. After counting and processing the standard pulse signal , obtain the activity concentrations of artificial α nuclides, artificial β nuclides and γ nuclides in atmospheric aerosols.

Further, the automatic control module 3 receives the radioactive detection signal output by the measurement module 2, processes it, stores it locally, displays it on the display screen, and simultaneously transmits the data to the cloud synchronously.

In step S2, the detection unit receives the radioactive rays of the aerosol on the filter paper 12, and the data processing unit outputs signals of α rays, β rays and γ rays. After processing the signals, the natural radon thoron daughter bodies ²¹² Po, ²¹⁴ Po and ²¹⁸ are obtained. The activity concentration of Po nuclide. Specifically, the preamplifier of the data processing unit outputs the signal S _αβγ of the first detector and the signal S _βγ of the second detector, and the multi-channel pulse analyzer of the data processing unit stores the signal S _αβγ and the signal S _βγ at different energy levels. area, fit the counts in different energy areas to obtain ²¹² Po energy spectrum, ²¹² Bi energy spectrum, ²¹⁴ Po energy spectrum and ²¹⁸ Po energy spectrum, and perform interval coincidence and anti-coherence between different energy areas to obtain natural radon Alpha spectrum of thoron daughter, respectively calculate the activity concentration of natural radon thoron daughter ²¹² Po ²¹⁴ Po activity concentration/> And the activity concentration of ²¹⁸ Po/>

In some embodiments, the multi-channel pulse analyzer stores the signal S _αβγ in four energy regions according to different energies, including energy regions ROI1, ROI2, ROI3 and ROI4, and stores the signal S _βγ in the ROI1' energy region. The counts in the ROI4 energy region are fitted to obtain ^{the 212} Po energy spectrum, and the interference counts generated in the ROI3 and ROI4 energy regions are deducted. The ^{212 Bi energy spectrum is deduced from the ratio of 212 Po} and ²¹² Bi counts, and the interference counts generated in the ROI2 energy region are deducted. The counts in the ROI3 energy region after deducting interference are fitted to obtain the ²¹⁴ Po energy spectrum, and the interference counts generated in the ROI2 and ROI3 energy regions are deducted. The counts in the ROI2 energy region after subtracting the interference are fitted to obtain ^{the 218} Po energy spectrum, and the interference counts generated in the ROI2 energy region are deducted. Perform interval coincidence between the ROI1 energy region of the signal S _αβγ and the ROI1' energy region of the signal S _βγ to generate the β signal S _β' , and perform anti-coherence between the signal S _αβγ and the signal S _βγ to generate the α signal S _α' . The α signal S _α' was matched with the three energy regions ROI2, ROI3 and ROI4 after deducting the interference counts respectively to obtain the α spectrum of the natural radon thoron daughter, and the activity concentration of the natural radon thoron daughter ²¹² Po was calculated respectively. ²¹⁴ Po activity concentration/> And the activity concentration of ²¹⁸ Po/>

Based on the activity concentrations of the above-mentioned natural radon thoron daughter ²¹² Po, ²¹⁴ Po and ²¹⁸ Po nuclides, the activity concentrations of the natural α nuclides and natural beta nuclides produced by the natural radon thoron daughter were calculated, combined with the activity concentrations in atmospheric aerosols. The activity concentrations of total α nuclides and total β nuclides are used to calculate the activity concentrations of artificial α nuclides and artificial β nuclides in atmospheric aerosols; the activity concentrations of γ nuclides in atmospheric aerosols are calculated.

Specifically, formula (I) is used to calculate the activity concentration A(β) of the natural β nuclide, and formula (II) is used to calculate the activity concentration A(α) of the natural α nuclide. Formula (I) and formula (II) Expressed as follows:

Among them, a, b, and c are the activity factors corresponding to the β energy spectrum of ²¹² Po, ²¹⁴ Po, and ²¹⁸ Po nuclides respectively, are the activity concentrations of ²¹² Po, ²¹⁴ Po, and ²¹⁸ Po nuclides respectively. Specifically, the values of a, b, and c are as follows: a=5.264, b=1, c=0.67.

Among them, d and e are the activity factors corresponding to the α energy spectrum of ²¹² Po and ²¹⁴ Po nuclides respectively, are the activity concentrations of ²¹² Po and ²¹⁴ Po nuclides respectively. Specifically, the values of d and e are as follows: d=3.125, e=2.

Based on the counts of α nuclides, β nuclides and γ nuclides, nuclide detection efficiency, aerosol sampling volume and measurement time, the total α nuclides, total β nuclides and γ are calculated using formulas (III)-(V) The activity concentration of the nuclide, formula (III)-(V) is expressed as follows:

Among them, N _α is the total count of α nuclide, N _α0 is the background count of α nuclide, f _α is the detection efficiency of α nuclide, V is the sampling volume, and T is the measurement time.

Among them, N _β is the total count of β nuclide, N _β0 is the background count of β nuclide, f _β is the detection efficiency of β nuclide, V is the sampling volume, and T is the measurement time.

Among them, N _γ is the total count of γ nuclide, N _γ0 is the background count of γ nuclide, f _γ is the detection efficiency of γ nuclide, V is the sampling volume, and T is the measurement time.

Further, by subtracting the activity concentration A(α) of the natural α nuclide from the activity concentration A′(α) of the total α nuclide, the activity concentration of the artificial α nuclide can be obtained. In the same way, the activity concentration of the artificial β nuclide can be obtained. The activity concentration of the nuclide; the activity concentration of the γ nuclide is calculated from the above formula (V).

The parts not described in detail in the present invention are all existing technologies.

It can be understood that the above embodiments only express the preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the present invention; it should be noted that for those of ordinary skill in the art, In other words, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the present invention; therefore, anything falling within the scope of the claims of the present invention All equivalent transformations and modifications shall fall within the scope of the claims of the present invention.

Claims (10)

1. The online monitoring device for the radioactivity of the atmospheric aerosol is characterized by comprising an acquisition module (1), a measurement module (2) and an automatic control module (3);

the measuring module (2) comprises a detecting unit, a shielding unit and a data processing unit, wherein the detecting unit is positioned in the shielding unit and is connected with the data processing unit;

the collecting module (1) is arranged in front of the measuring module (2), the collecting module (1) comprises a sampling unit and a paper feeding unit, the sampling unit comprises a sampling container (11), the paper feeding unit comprises filter paper (12) and a driving motor for driving the filter paper (12) to move, and the filter paper (12) sequentially penetrates through the sampling container (11) and the shielding unit to move;

the signal output end of the automatic control module (3) is respectively connected with the signal input ends of the acquisition module (1) and the measurement module (2).

2. The online monitoring device of atmospheric aerosol radioactivity according to claim 1, wherein the shielding unit comprises a vacuum chamber (23) and a shielding body (22) positioned in the vacuum chamber (23), the filter paper (12) is penetrated in the vacuum chamber (23), and the vacuum chamber (23) is provided with a sealing gasket at a position contacted with the filter paper (12); the shielding body (22) comprises a first shielding body and a second shielding body which are symmetrically arranged on the front surface and the back surface of the filter paper (12), and the first shielding body and the second shielding body are combined to form a detection inner cavity;

the detection unit is located in the detection cavity and is arranged at a position close to the surface of the filter paper (12).

3. The on-line monitoring device of atmospheric aerosol radioactivity according to claim 1, characterized in that the detection unit comprises a detector (21) and a photomultiplier, the detector (21) comprising a first detector receiving alpha rays, beta rays and gamma rays and a second detector receiving beta rays and gamma rays, the first and second detectors being symmetrically arranged on the front and back of the filter paper (12); one end of the photomultiplier is connected with the detector (21), and the other end of the photomultiplier is connected with the data processing unit;

the data processing unit comprises a preamplifier, a multichannel pulse analyzer and a logic circuit, and the output end of the data processing unit is connected with the industrial personal computer (4).

4. The online monitoring device of atmospheric aerosol radioactivity according to claim 1, wherein the paper feeding unit further comprises a paper feeding wheel (16), a guide roller (18) and a paper collecting wheel (17), the paper collecting wheel (17) is connected to the driving motor, the paper feeding wheel (16) and the paper collecting wheel (17) are symmetrically arranged at two sides of the sampling unit and the measuring module (2), two ends of the filter paper (12) are respectively wound on the paper feeding wheel (16) and the paper collecting wheel (17), and the guide roller (18) is arranged between the paper feeding wheel (16) and the paper collecting wheel (17); the filter paper (12) is sequentially conveyed to the guide roller (18) and the paper collecting wheel (17) by the paper feeding wheel (16).

5. The online monitoring device of atmospheric aerosol radioactivity according to claim 1, wherein the sampling unit further comprises a gas channel (112) and a sampling fan (15), the gas channel (112) is connected to the gas outlet of the sampling container (11), the sampling fan (15) is connected to the outlet of the gas channel (112), and the gas channel (112) is further provided with a first pressure sensor (13) and a mass flowmeter (14);

the movement of the filter paper (12) passes through the air inlet (111) of the sampling vessel (11).

6. An on-line monitoring device of atmospheric aerosol radioactivity according to claim 1, characterized in that the automatic control module (3) comprises a main control unit for processing, displaying, storing and transmitting monitoring data, and an alarm unit for alarming abnormal monitoring results and equipment faults.

7. The on-line monitoring device of atmospheric aerosol radioactivity according to any one of claims 1 to 6, further comprising a housing, wherein the acquisition module (1) and the measurement module (2) are both located inside the housing, and wherein the automatic control module (3) is located outside the housing.

8. An on-line monitoring method of atmospheric aerosol radioactivity, characterized in that an on-line monitoring device of atmospheric aerosol radioactivity according to any one of claims 1 to 7 is employed, comprising the steps of:

s1, sampling: the automatic control module (3) sends out a sampling signal, the paper feeding unit responds to the sampling signal and then transmits the filter paper (12) to the sampling unit, the sampling unit deposits aerosol in the atmosphere on the surface of the filter paper (12), the automatic control module (3) generates a transmission signal according to a sampling feedback signal output by the sampling unit, and the paper feeding unit responds to the transmission signal and transmits the filter paper (12) to the detection unit;

s2, measuring: the automatic control module (3) generates detection signals according to the transmission feedback signals output by the paper feeding unit, the detection unit responds to the detection signals and then detects the filter paper (12), and the data processing unit processes the radioactive signals output by the detection unit to obtain the activity concentrations of the artificial alpha nuclide, the artificial beta nuclide and the gamma nuclide in the atmospheric aerosol.

9. The method for on-line monitoring of atmospheric aerosol radioactivity according to claim 8, wherein the detection unit receives the radioactive rays of the aerosol on the filter paper (12), the data processing unit outputs signals of alpha rays, beta rays and gamma rays, and the signals are subjected toAfter treatment, natural radon thorium daughter is obtained ²¹² Po、 ²¹⁴ Po and ²¹⁸ the activity concentration of the Po species;

calculating the activity concentrations of natural alpha nuclides and natural beta nuclides generated by the natural radon thorium daughter according to the nuclide activity concentrations of the natural radon thorium daughter, and calculating the activity concentrations of artificial alpha nuclides and artificial beta nuclides in the atmospheric aerosol by combining the activity concentrations of the total alpha nuclides and the total beta nuclides in the atmospheric aerosol; the activity concentration of gamma nuclides in the atmospheric aerosol is calculated.

10. The method for on-line monitoring of atmospheric aerosol radioactivity according to claim 9, wherein the activity concentration a (β) of the natural β -nuclide is calculated using formula (i), the activity concentration β (α) of the natural α -nuclide is calculated using formula (ii), and the formula (i) and the formula (ii) are represented as follows:

wherein a, b and c are respectively ²¹² Po、 ²¹⁴ Po、 ²¹⁸ The activity factor corresponding to the beta energy spectrum of the Po nuclide,respectively is ²¹² Po、 ²¹⁴ Po、 ²¹⁸ The activity concentration of the Po species;

wherein d and e are respectively ²¹² Po、 ²¹⁴ An activity factor corresponding to the alpha energy spectrum of the Po nuclide, respectively is ²¹² Po、 ²¹⁴ Activity concentration of Po nuclides.