CN117607938A - Online monitoring device and online monitoring method for atmospheric aerosol radioactivity - Google Patents
Online monitoring device and online monitoring method for atmospheric aerosol radioactivity Download PDFInfo
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- 239000005427 atmospheric aerosol Substances 0.000 title claims abstract description 38
- 238000012544 monitoring process Methods 0.000 title claims abstract description 31
- 238000012806 monitoring device Methods 0.000 title claims abstract description 26
- 238000000034 method Methods 0.000 title claims abstract description 17
- 238000005070 sampling Methods 0.000 claims abstract description 85
- 238000001514 detection method Methods 0.000 claims abstract description 53
- 238000012545 processing Methods 0.000 claims abstract description 35
- 238000005259 measurement Methods 0.000 claims abstract description 28
- 230000000694 effects Effects 0.000 claims description 54
- 239000000443 aerosol Substances 0.000 claims description 29
- 230000002285 radioactive effect Effects 0.000 claims description 21
- 238000001228 spectrum Methods 0.000 claims description 19
- 229910052704 radon Inorganic materials 0.000 claims description 17
- SYUHGPGVQRZVTB-UHFFFAOYSA-N radon atom Chemical compound [Rn] SYUHGPGVQRZVTB-UHFFFAOYSA-N 0.000 claims description 17
- ZSLUVFAKFWKJRC-IGMARMGPSA-N 232Th Chemical compound [232Th] ZSLUVFAKFWKJRC-IGMARMGPSA-N 0.000 claims description 16
- 229910052776 Thorium Inorganic materials 0.000 claims description 16
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- 230000007613 environmental effect Effects 0.000 abstract description 4
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- 241000894007 species Species 0.000 description 2
- XQVKLMRIZCRVPO-UHFFFAOYSA-N 4-[(2-arsonophenyl)diazenyl]-3-hydroxynaphthalene-2,7-disulfonic acid Chemical compound C12=CC=C(S(O)(=O)=O)C=C2C=C(S(O)(=O)=O)C(O)=C1N=NC1=CC=CC=C1[As](O)(O)=O XQVKLMRIZCRVPO-UHFFFAOYSA-N 0.000 description 1
- 241000282414 Homo sapiens Species 0.000 description 1
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- 241000679125 Thoron Species 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/167—Measuring radioactive content of objects, e.g. contamination
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/1603—Measuring radiation intensity with a combination of at least two different types of detector
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/17—Circuit arrangements not adapted to a particular type of detector
- G01T1/178—Circuit arrangements not adapted to a particular type of detector for measuring specific activity in the presence of other radioactive substances, e.g. natural, in the air or in liquids such as rain water
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/24—Measuring radiation intensity with semiconductor detectors
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T7/00—Details of radiation-measuring instruments
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T7/00—Details of radiation-measuring instruments
- G01T7/02—Collecting means for receiving or storing samples to be investigated and possibly directly transporting the samples to the measuring arrangement; particularly for investigating radioactive fluids
- G01T7/04—Collecting means for receiving or storing samples to be investigated and possibly directly transporting the samples to the measuring arrangement; particularly for investigating radioactive fluids by filtration
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
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- Measurement Of Radiation (AREA)
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
Technical Field
The invention relates to the technical field of radiation environment monitoring, in particular to an online monitoring device and an online monitoring method for atmospheric aerosol radioactivity.
Background
Along with the development of science and technology, the utilization of nuclear energy is also more and more widespread, and a large amount of alpha nuclides, beta nuclides and gamma nuclides are released to the environment, and the radiation influence is caused to human beings through external irradiation and internal irradiation, so that the monitoring of radioactive aerosol has become an important content of conventional radiation environment monitoring and nuclear emergency monitoring. The total alpha, beta and gamma nuclides in the environment are divided into natural radionuclides and artificial radionuclides, wherein the natural radionuclides mainly originate from ground radionuclides 238 U and 232 th decay release 222 Rn and 220 rn and decay daughter thereof, and humansAlpha-nuclides, beta-nuclides and gamma-nuclides generated by the decay of an industrial radionuclide are the object of interest in environmental monitoring, the activity concentration of which is usually extremely low, and the interference of natural nuclides needs to be deducted during monitoring.
The existing radioactive aerosol monitoring device and instrument have the problems of small sampling flow, small sampling volume, poor reliability, low integration level and the like; meanwhile, due to the defects of design principles or algorithms, a plurality of radioactive aerosol monitoring devices cannot accurately measure and reject natural radioactive aerosol radon thorium, decay daughter and gamma rays, false alarm events caused by inaccurate measurement results or natural radioactive interference often occur in the use process, normal use of equipment is seriously affected, and the accurate measurement capability of the equipment is greatly weakened. The current general monitoring mode of the nuclear power plant adopts a large-flow sampler to sample aerosol and send the aerosol back to a laboratory for analysis, and the method is time-consuming and labor-consuming, and can not find abnormal leakage and accident release of the nuclear facility in time.
Disclosure of Invention
The invention aims to solve the technical problem of providing an on-line monitoring device and an on-line monitoring method for atmospheric aerosol radioactivity.
The technical scheme adopted for solving the technical problems is as follows: an online monitoring device for atmospheric aerosol radioactivity 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.
Preferably, the shielding unit comprises a vacuum chamber and a shielding body positioned in the vacuum chamber, the filter paper is penetrated in the vacuum chamber, and a sealing gasket is arranged at the position of the vacuum chamber, which is contacted with the filter paper; the shielding body 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, and the first shielding body and the second shielding body are combined to form a detection inner cavity;
the detection unit is positioned in the detection cavity and is arranged at a position close to the surface of the filter paper.
Preferably, the detection unit comprises a detector and a photomultiplier, the detector comprises a first detector and a second detector, the first detector receives alpha rays, beta rays and gamma rays, the second detector receives beta rays and gamma rays, and the first detector and the second detector are symmetrically arranged on the front surface and the back surface of the filter paper; one end of the photomultiplier is connected with the detector, 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.
Preferably, the paper feeding unit further comprises a paper feeding wheel, a guide roller and a paper collecting wheel, wherein the paper collecting wheel is connected with the driving motor, the paper feeding wheel and the paper collecting wheel are symmetrically arranged on two sides of the sampling unit and the measuring module, two ends of the filter paper are respectively wound on the paper feeding wheel and the paper collecting wheel, and the guide roller is arranged between the paper feeding wheel and the paper collecting wheel; the filter paper is sequentially transmitted to the guide roller and the paper collecting wheel by the paper feeding wheel.
Preferably, the sampling unit further comprises 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 further provided with a first pressure sensor and a mass flowmeter;
the movement of the filter paper passes through the air inlet of the sampling vessel.
Preferably, the automatic control module comprises a main control unit for processing, displaying, storing and transmitting the monitoring data, and an alarm unit for alarming abnormal monitoring results and equipment faults.
Preferably, the on-line monitoring device further comprises a shell, the acquisition module and the measurement module are both located in the shell, and the automatic control module is located outside the shell.
The online monitoring method for the radioactivity of the atmospheric aerosol adopts the online monitoring device for the radioactivity of the atmospheric aerosol, and the online monitoring method comprises the following steps:
s1, sampling: the automatic control module sends out a sampling signal, the paper feeding unit responds to the sampling signal and then transmits the filter paper to the sampling unit, the sampling unit deposits aerosol in the atmosphere on the surface of the filter paper, the automatic control module 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 to the detection unit;
s2, measuring: the automatic control module 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, 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.
Preferably, the detection unit receives the radioactive rays of the aerosol on the filter paper, the data processing unit outputs signals of alpha rays, beta rays and gamma rays, and natural radon thoron daughter is obtained after the signals are processed 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.
Preferably, the activity concentration A (beta) of the natural beta nuclide is calculated by using a formula (I), and the activity concentration A (alpha) of the natural alpha nuclide is calculated by using a formula (II), wherein the formula (I) and the formula (II) are expressed as follows:
wherein a, b and c are respectively 212 Po、 214 Po、 218 Living organism corresponding to beta energy spectrum of Po nuclideThe degree factor is used to determine the degree of the object,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.
The invention has the beneficial effects that:
the online monitoring device adopts a modularized design, and all modules work cooperatively, so that the real-time online continuous monitoring of the radioactivity of the atmospheric aerosol is realized according to the processes of sampling, measuring and data processing. The sampling module and the measuring module are arranged separately, so that measurement can be performed while sampling. In addition, the collected gas is filtered by filter paper in the sampling container, and the collected gas is not leaked out so as to avoid polluting the detection unit. The aerosol radioactivity detection is carried out in the shielding unit, so that the environment background value can be reduced, the alpha energy spectrum resolution is improved, the interference of natural radon thorium daughter can be effectively screened, the influence of environment humidity can be reduced, and the environment adaptation capability of the detection unit is improved.
The online monitoring method of the invention sends corresponding signals to the paper feeding unit, the sampling unit, the detection unit and the data processing unit through the automatic control module, and realizes filter paper sampling, filter paper transportation, filter paper radioactive detection and radioactive signal processing, thereby obtaining the activity concentrations of artificial alpha nuclide, artificial beta nuclide and gamma nuclide in the atmospheric aerosol.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a schematic diagram of an on-line monitoring device for atmospheric aerosol radioactivity in accordance with the present invention;
the reference numerals in the drawings are as follows: 1. an acquisition module; 11. a sampling container; 111. an air inlet; 112. a gas channel; 12. a filter paper; 13. a first pressure sensor; 14. a mass flowmeter; 15. a sampling fan; 16. a paper feed wheel; 17. a paper collecting wheel; 18. a guide roller; 2. a measurement module; 21. a detector; 22. a shield; 23. a vacuum chamber; 231. a vacuum channel; 24. a second pressure sensor; 25. a vacuum pump; 26. a vacuum conversion head; 3. an automatic control module; 4. and the industrial personal computer.
Detailed Description
For a clearer understanding of technical features, objects and effects of the present invention, a detailed description of embodiments of the present invention will be made with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "rear", "upper", "lower", "left", "right", "longitudinal", "transverse", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail", etc. are configured and operated in specific directions based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention, and do not indicate that the apparatus or element to be referred to must have specific directions, and thus should not be construed as limiting the present invention.
It should also be noted that unless explicitly stated or limited otherwise, terms such as "mounted," "connected," "secured," "disposed," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the 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," and the like are used merely for convenience in describing the present invention and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, whereby features defining "first," "second," "third," etc. may explicitly or implicitly include one or more such features. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
As shown in fig. 1, an online monitoring device for radioactivity of an atmospheric aerosol according to some embodiments of the present invention is used for monitoring a change trend of the radioactive aerosol in an atmospheric environment in real time, and the online monitoring device includes an acquisition module 1, a measurement module 2 and an automatic control module 3. The collection module 1 is used for collecting aerosol samples from the atmosphere by introducing air to deposit the aerosol on the filter paper 12. The measurement module 2 is used for measuring a radioactive signal emitted by the aerosol sample on the filter paper 12 and processing the radioactive signal to obtain the activity concentrations of the total alpha nuclide, the total beta nuclide and the gamma nuclide in the aerosol sample. The automatic control module 3 is used for carrying out logic control on the acquisition module 1 and the measurement module 2 so as to complete logic functions such as acquisition, measurement, data processing and the like and ensure the automatic continuous normal operation of the on-line monitoring device.
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 the detecting unit is connected with the data processing unit. The shielding unit comprises a vacuum chamber 23 and a shielding body 22 positioned in the vacuum chamber 23, and the filter paper 12 is penetrated in the vacuum chamber 23. The vacuum chamber 23 is provided with a sealing gasket at a position contacting the filter paper 12, so that the vacuum chamber 23 can maintain a sealing state when vacuuming, and the accuracy of aerosol radioactivity detection is improved. The vacuum chamber 23 is connected with the vacuum channel 231, the outlet of the vacuum channel 231 is provided with the vacuum pump 25 connected with the automatic control module 3, and the vacuum pump 25 vacuumizes the vacuum chamber 23, so that the influence of radioactive aerosol radon thorium daughter tailing during measurement can be reduced. The vacuum channel 231 is provided with a second pressure sensor 24 for performing differential pressure test on the vacuum pump 25 corresponding to the vacuum channel 231 to ensure normal operation thereof. 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, 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 of the shielding body 22 and is arranged at a position close to the surface of the filter paper 12, the environmental background value is reduced through the shielding body 22, and the influence of the environmental background on the radioactive detection of the artificial aerosol is reduced. In some embodiments, the shield 22 is generally a square body with a detection lumen inside, and the shield 22 may be made of lead material with a wall thickness of 3-7cm.
The detection unit comprises a detector 21 for receiving the radioactive rays emitted by the aerosol on the filter paper 12 and a photomultiplier for signal enhancement. The detector 21 includes a first detector that receives the α -ray, the β -ray, and the γ -ray, and a second detector that receives the β -ray and the γ -ray, which are symmetrically arranged on the front and back sides of the filter paper 12. In some embodiments, the detector 21 is a PIPS detector. The photomultiplier is located at the rear end of the detector 21 and is connected to the detector 21, and the other end of the photomultiplier is connected to the data processing unit. It will be appreciated that the detector 21 and photomultiplier tube may be of the prior art and that the present invention will not be described in detail herein.
The data processing unit includes a preamplifier, a multi-channel pulse analyzer, and a logic circuit. The detection lumen of the shielding 22 of the detection unit is provided with a vacuum transducer head 26 to provide a vacuum environment, the vacuum transducer head 26 connecting the preamplifier and the multichannel pulse analyzer. In some embodiments, the output end of the data processing unit is connected with the industrial personal computer 4 as an upper computer, the industrial personal computer 4 is used for program control of the whole device, including control of the acquisition module 1, the measurement module 2 and the automatic control module 3, and meanwhile, the industrial personal computer 4 also completes functions of final data calculation, storage and the like. It should be understood that the preamplifiers, the multichannel pulse analyzer, the logic circuits, the vacuum conversion head 26 and the industrial personal computer 4 can all be implemented by the prior art, and the present invention is not repeated herein.
The collection module 1 is arranged in front of the measurement module 2, the collection 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 (not shown) 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 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 vessel 11, specifically, the angle α between the movement direction of the filter paper 12 and the air inlet direction of the sampling vessel 11 is 90 ° or more α > 0 °, and it is understood that the movement direction of the filter paper 12 is not parallel to the air inlet direction of the sampling vessel 11. Further, the angle α between the moving direction of the filter paper 12 and the air intake direction of the sampling container 11 is preferably 90 °, which is advantageous for the air to be filtered through the filter paper 12, so that the aerosol in the air is sufficiently deposited on the filter paper 12.
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, the sampling fan 15 is an air extraction fan, the sampling module 1 drives air to enter the sampling unit through the sampling fan 15, and aerosol in the air is 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 flowmeter 14, wherein the first pressure sensor 13 is used for recording the pressure difference in the gas channel 112, the mass flowmeter 14 is used for controlling the gas flow in a feedback manner and recording the air sampling amount, and when the gas flow does not accord with the program setting, an alarm is triggered; when the preset air sampling amount or the preset sampling time is reached, the collecting module 1 transfers the filter paper 12 with the aerosol sample collected to the measuring module 2.
The paper feeding unit further comprises a paper feeding wheel 16, a guide roller 18 and a paper collecting wheel 17, wherein the paper collecting wheel 17 is connected to a driving motor, and the driving motor is electrically connected with the automatic control module 3. 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, and two ends of the filter paper 12 are respectively wound on the paper feeding wheel 16 and the paper collecting wheel 17. The guide roller 18 is arranged between the paper feeding wheel 16 and the paper collecting wheel 17, a plurality of guide rollers 18 can be arranged, the guide rollers 18 are positioned on the same horizontal plane, and particularly can be arranged in front of the sampling container 11 and behind the vacuum chamber 23, the guide roller 18 can also be arranged between the sampling container 11 and the vacuum chamber 23, and can guide and tension the filter paper 12 for the transmission of the filter paper 12, so that the filter paper 12 is kept straight in the transmission process. The height of the plane of the paper feeding wheel 16 and the paper collecting wheel 17 is lower than the height of the plane of the guide roller 18, the guide roller 18 is positioned on the lower surface side of the filter paper 12, and the filter paper 12 is closely attached to the guide roller 18. In the transmission process of the filter paper 12, the automatic control module 3 controls the driving motor to drive the paper collecting wheel 17 to rotate, the paper collecting wheel 17 drives the filter paper 12 to be sequentially transmitted to the guide roller 18 and the paper collecting wheel 17 by the paper feeding wheel 16, and aerosol samples on the filter paper 12 are transmitted to the paper collecting wheel 17 for storage along with the filter paper 12 after measurement is completed, so that continuous and accumulated collection of the atmospheric aerosol samples, storage and collection of the aerosol samples and subsequent replacement of the filter paper 12 are realized.
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. The automatic control module 3 includes a main control unit for processing, displaying, storing and transmitting the monitoring data, and an alarm unit for alarming the abnormal monitoring result and the equipment failure. The alarm unit can automatically alarm abnormal monitoring results when the radioactivity monitoring results exceed a preset alarm threshold value, and automatically alarm equipment faults when the sampling fan 15 fails, the gas channel 112 is blocked or leaks, the filter paper 12 breaks or is defective, the detector 21 has no counting signal and other fault conditions.
In some embodiments, the on-line monitoring device further comprises a housing, wherein the acquisition module 1 and the measurement module 2 are both positioned in the housing, and the automatic control module 3 is positioned outside the housing. The sampling unit of the acquisition module 1 further comprises an air inlet channel (not shown) inserted in the housing, and an air outlet of the air inlet channel is connected to the air inlet 111 of the sampling container 11. The air inlet channel is provided with a sealing piece at the contact position with the shell, so that the inside of the shell is in a sealing state.
The invention also provides an online monitoring method of the atmospheric aerosol radioactivity, which adopts the online monitoring device of the atmospheric aerosol radioactivity and comprises the following steps:
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, and 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 the sampling feedback signal output by the sampling unit, and the paper feeding unit transmits the filter paper 12 to the detection unit, specifically to the detection inner cavity of the shielding body 22 in response to the transmission signal.
S2, measuring: the automatic control module 3 generates a detection signal according to a transmission feedback signal output by the paper feeding unit, the detection unit responds to the detection signal and then detects the filter paper 12 in the detection cavity, the data processing unit processes the radioactive signal output by the detection unit, specifically, the detection unit receives radioactive rays of aerosol samples deposited on the filter paper 12, the data processing unit performs screening, shaping, amplifying and converting processing on the radioactive signal output by the detection unit and outputs a standard pulse signal, and the activity concentration of artificial alpha nuclides, artificial beta nuclides and gamma nuclides in the atmospheric aerosol is obtained after the standard pulse signal is counted and processed.
Further, the automatic control module 3 receives the radioactivity detection signal output by the measurement module 2, processes the radioactivity detection signal, stores the radioactivity detection signal locally, displays the radioactivity detection signal through a display screen, and synchronously transmits data to the cloud.
In the S2 step, 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 processed to obtain natural radon thorium daughter 212 Po、 214 Po and 218 activity concentration of Po nuclides. Specifically, the pre-amplifier of the data processing unit outputs a signal S of the first detector αβγ Signal S of the second detector βγ The multichannel pulse analyzer of the data processing unit applies the signal S αβγ Sum signal S βγ Stored in different energy regions, and the counts of the different energy regions are fitted to obtain 212 Po energy spectrum, 212 Bi energy spectrum, 214 Po energy spectrum 218 Po energy spectrum, interval coincidence and anti-coincidence are carried out between different energy regions to obtain alpha spectrum of natural radon thorium daughter, and the alpha spectrum of natural radon thorium daughter is calculated respectively 212 Activity concentration of Po 214 Activity concentration of Po->And 218 activity concentration of Po->
In some embodiments, the multichannel pulse analyzer applies the signal S αβγ Respectively storing the signals S in 4 energy regions including energy regions ROI1, ROI2, ROI3 and ROI4 according to the energy difference βγ Stored in the ROI1' region. Fitting the count of the ROI4 energy region to obtain 212 Po energy spectrum and deduct the interference counts it produces in ROI3 and ROI4 energy regions. By passing through 212 Po and 212 the ratio relation of Bi counts is calculated 212 Bi energy spectrum and deduct the interference count generated in the ROI2 energy region. Fitting the counts of the ROI3 energy regions after deduction and interference removal to obtain 214 Po energy spectrum and deduct the interference counts it produces in ROI2 and ROI3 energy regions. Fitting the counts of the ROI2 energy regions after deduction and interference removal to obtain 218 Po energy spectrum and deduct its interference count generated in ROI2 energy region. For signal S αβγ ROI1 region of energy and signal S βγ Region-wise fitting of the region of interest (ROI 1') to generate a beta signal S β’ For signal S αβγ Sum signal S βγ Performing anti-coincidence to generate alpha signal S α’ . Will be alpha signal S α’ And the energy areas of the three energy areas ROI2, ROI3 and ROI4 after deducting the interference count are respectively matched to obtain alpha spectrums of the natural radon thorium daughter, and the alpha spectrums of the natural radon thorium daughter are respectively calculated to obtain the natural radon thorium daughter 212 Activity concentration of Po 214 Activity concentration of Po->And 218 activity concentration of Po->
According to the natural radon thorium daughter 212 Po、 214 Po and 218 the activity concentration of Po nuclide calculates the activity concentration of natural alpha nuclide and natural beta nuclide generated by natural radon thorium daughter, and combines the activity concentration of total alpha nuclide and total beta nuclide in the atmospheric aerosol to calculate the activity concentration of artificial alpha nuclide and artificial beta nuclide in the atmospheric aerosol; the activity concentration of gamma nuclides in the atmospheric aerosol is calculated.
Specifically, the activity concentration A (beta) of the natural beta nuclide is calculated by adopting a formula (I), and the activity concentration A (alpha) of the natural alpha nuclide is calculated by adopting a formula (II), wherein the formula (I) and the formula (II) are shown 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 Activity concentration of Po nuclides. Specifically, the values of a, b, and c are as follows: a=5.264, b=1, c=0.67.
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. Specifically, the values of d and e are as follows: d=3.125, e=2.
Calculating the activity concentration of the total alpha nuclide, the total beta nuclide and the gamma nuclide by adopting formulas (III) - (V) according to the counts of the alpha nuclide, the beta nuclide and the gamma nuclide, the nuclide detection efficiency, the sampling volume of aerosol and the measurement time, wherein the formulas (III) - (V) are as follows:
wherein N is α For alpha nuclide total count, N α0 For alpha nuclide background count, f α The alpha nuclide detection efficiency is that V is the sampling volume and T is the measurement time.
Wherein N is β For beta nuclide total count, N β0 For beta nuclide background count, f β The beta nuclide detection efficiency is that V is the sampling volume and T is the measurement time.
Wherein N is γ For total counts of gamma nuclides, N γ0 Background count for gamma nuclide, f γ The gamma nuclide detection efficiency is that V is the sampling volume and T is the measurement time.
Further, subtracting the activity concentration A (alpha) of the natural alpha nuclide from the activity concentration A' (alpha) of the total alpha nuclide to obtain the activity concentration of the artificial alpha nuclide, and obtaining the activity concentration of the artificial beta nuclide in the same manner; the activity concentration of gamma nuclides is calculated from formula (V) above.
The invention is not described in detail in the prior art.
It is to be understood that the above examples only represent preferred embodiments of the present invention, which are described in more detail and are not to be construed as limiting the scope of the invention; it should be noted that, for a person skilled in the art, the above technical features can be freely combined, and several variations and modifications can be made without departing from the scope of the invention; therefore, all changes and modifications that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
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.
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