Device and method for measuring radon concentration in open environment

Abstract

The invention discloses a radon concentration measuring device and method in an open environment, and relates to the technical field of gas radon concentration measurement. The radon concentration measuring device in the open environment comprises a daughter collecting assembly and an induction processing assembly, the daughter collection assembly comprises a shell, filter paper and an air pump; the induction processing assembly comprises a shell, a shading film, a circuit board and a chip board; a CMOS image sensor is installed on the circuit board, an SoC chip is installed on the chip board, and the chip board is in communication connection with the circuit board. The gas radon concentration measuring method is based on the radon concentration measuring device in the open environment. The device has the advantages that the structure is simple, the size is small, carrying is convenient, compared with a radon concentration measuring device in the background technology, improvement is conducted from the technical route level, different measuring media (radioactive aerosol) are selected, a collecting structure of the measuring media is correspondingly designed, and the device is suitable for gas radon concentration measurement in the open environment (outdoor environment).

Description

Technical Field

[0001] The present invention relates to the technical field of radon concentration measurement, in particular to a radon concentration measurement device and method in an open environment. Background Art

[0002] Radon ( 222 Rn) is a colorless and odorless natural radioactive gas, commonly found in rocks and soil 226 and is the α decay product of

[0003] Ra. After radon decays, it produces a series of more radioactive daughters. Radon daughters have a strong adhesion ability and are easily attached to dust and water droplets in the air, forming radioactive aerosols. Once the radioactive aerosols are inhaled by the human body, the radiation they produce will increase the risk of lung cancer, and its harm to the lungs is second only to smoking. Therefore, it is very necessary to measure the radon concentration in the environment (especially the radon concentration in the indoor environment).

[0004] The above radon concentration measurement device has the following deficiencies in practical applications:

[0005] 1. According to the description of its components and application scenarios, it is only applicable to the measurement of radon concentration in a closed environment (radon chamber), and it is large in size and does not have the attribute of being portable, making it difficult to be applied to the measurement of radon concentration in an open environment or special outdoor scenarios.

[0006] 2. After starting the measurement, it is first necessary to wait for radon to decay into Po-218 and Po-214 before it can be captured by the electrostatic field. Then, it is necessary to wait for Po-128 and Po-214 to drift towards the metal thin layer and finally land on the metal thin layer. And due to the small size of the metal thin layer (the surface size of the metal thin layer is the same as the photosensitive surface size of the CMOS image sensor), the waiting time is further extended.

[0007] 3. The glass encapsulation on the surface of the CMOS image sensor is to ensure that visible light can pass through while preventing dust and protecting the internal circuit. The central area of the CMOS image sensor is a pixel array. The electrodes of most commercial CMOS image sensors are also arranged on the surface. In addition, a Bayer array transparent insulating material layer (very thin) for forming a color image is provided on the surface. After the glass encapsulation on the surface of the CMOS image sensor is removed, the metal thin layer is directly vapor-deposited on the insulating material layer. If the voltage provided by the high-voltage module is too high, it is easy to break down the insulating material layer, causing a short circuit and scrapping the CMOS image sensor. If the voltage provided by the high-voltage module is too low, the capture ability of the generated high-voltage electrostatic field for Po-218 and Po-214 will be weakened, extending the waiting time for the measurement result.

[0008] 4. After starting the measurement, the metal thin layer will enrich Po-218 and Po-214 when powered by high voltage. It is difficult to clean Po-218 and Po-214 on the metal thin layer completely, so it can only be used for one radon concentration measurement. And since the metal thin layer is integrated with the CMOS image sensor, a new CMOS image sensor vapor-deposited with the metal thin layer needs to be prepared for each radon concentration measurement, increasing the cost of radon concentration measurement.

[0009] 5. The metal thin layer is attached to the photosensitive surface of the CMOS image sensor. When the CMOS image sensor and the metal thin layer are respectively powered (the metal thin layer is powered by the high-voltage module and the CMOS image sensor is powered by the circuit board), they are prone to interfere with each other, causing current noise and thus affecting the stability of radon concentration measurement. Summary of the Invention

[0010] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a radon concentration measurement device and method in an open environment, which solves the problems that the existing radon concentration measurement device based on the CMOS sensor is not applicable to the radon concentration measurement in an open environment, has low measurement efficiency, high adjustment risk, and high use cost.

[0011] The technical solution of the present invention is: a radon concentration measurement device in an open environment, including a daughter body collection component and an induction processing component;

[0012] The daughter nuclide collection component includes a housing and a filter paper; the housing is of an integral or split structure, and an air path channel arranged in a T shape is provided inside the housing. One end of the air path channel forms an air inlet on the housing surface, and the other end of the air path channel forms an installation port and an exhaust port arranged oppositely on the housing surface; the filter paper is detachably installed inside the air path channel of the housing.

[0013] The induction processing component includes a housing, a light-shielding film, a circuit board and a chip board; one end of the housing is a docking end, an element cavity is provided inside the housing, and a ray hole is provided on the end face of the docking end of the housing; the light-shielding film is covered and installed on the ray hole of the housing; the housing is hermetically inserted into the installation port of the housing through the docking end, so that the light-shielding film and the filter paper are arranged opposite to each other without any obstacles; the circuit board and the chip board are both installed in the element cavity of the housing. A CMOS image sensor is installed on the circuit board, and the surface of the CMOS image sensor is not glass-packaged so that the photosensitive surface is exposed. The photosensitive surface of the CMOS image sensor and the light-shielding film are arranged opposite to each other without any obstacles. An SoC chip is installed on the chip board, and the chip board is communicatively connected to the circuit board.

[0014] A further technical solution of the present invention is that it further includes an air pump and a PC; the air inlet end of the air pump is communicated with the exhaust port of the housing through a pipeline, and the air outlet end of the air pump is communicated with the atmosphere; the PC is communicatively connected to the chip board, and the PC is used to store and process the frame image containing the radiation response signal output by the chip board.

[0015] A further technical solution of the present invention is that the distance between the photosensitive surface of the CMOS image sensor and the surface of the filter paper facing the CMOS image sensor is less than 5 mm.

[0016] A further technical solution of the present invention is that the housing and the housing are both made of light-tight and ray-shielding materials, and the light-shielding film is made of light-tight and ray-penetrating materials.

[0017] A further technical solution of the present invention is that the daughter nuclide collection component further includes clip pieces; the clip pieces are made of light-tight and ray-shielding materials, the clip pieces are installed inside the air path channel of the housing, the clip pieces are formed by buckling two sub-pieces with each other, and a hollow hole is provided at the center of each sub-piece. The filter paper is clamped and fixed between the two sub-pieces of the clip piece and covers the hollow holes of the two sub-pieces.

[0018] The technical solution of the present invention is: a method for measuring the radon concentration in air, based on a radon concentration measuring device in an open environment, characterized in that: before performing the measurement method, parameter adjustment software is installed on the PC, and the parameter adjustment software is used to call the register address of the CMOS image sensor and assign values to adjust the gain and integration time of the CMOS image sensor. On the PS machine, the integration time of the CMOS image sensor is set to be between 0.001 - 1 s and the gain is set to be between 1 - 100 dB through the parameter adjustment software;

[0019] The steps are as follows:

[0020] Place the radon concentration measuring device in the open environment into the environment to be measured, start the air pump, and make the air to be measured flow at a constant flow rate along the path of intake port - air path channel - filter paper - air path channel - exhaust port - air pump - external environment. During the flow of the air to be measured, the radioactive aerosol containing radon daughters is intercepted on the filter paper, and the air and gaseous radon can continue to flow through the filter paper; the α particles generated by the decay of the radon daughters on the filter paper pass through the light-shielding film and hit the surface of the CMOS image sensor, causing the CMOS image sensor to generate a radiation response signal; the chip board collects and processes the output data of the CMOS image sensor and converts it into a continuous frame image and transmits it to the PC; the PC counts the radiation response signals in the frame image and estimates the radon concentration based on this.

[0021] A further technical solution of the present invention is that the process of estimating the radon concentration based on the radiation response signal is as follows:

[0022] Ⅰ. In air, when 222 Rn and 218 Po reach decay equilibrium, 218 the concentration of Po is proportional to the concentration of 222 Rn, and the relationship between the two is shown in Formula 1;

[0023]

[0024] In the formula, C Po is the concentration of 218 Po, λ Rn is the decay constant of 222 Rn, λ Po is the decay constant of 218 Po, C Rn is the concentration of 222 Rn; during the air extraction process after starting the air pump, the number of 218 Po intercepted by the filter paper per unit time is shown in Formula 2; Formula 2: V Po = C Po ·Q; in the formula, V Po is the number of 218 Po intercepted by the filter paper per unit time, is the number of 218 Po contained in the gas per unit volume, and Q is the air extraction flow rate;

[0025] Ⅱ. During the air extraction process after starting the air pump, the 218 Po on the filter paper gradually accumulates and decays simultaneously, and the accumulation and decay of 218 Po are represented by a differential equation, as shown in Formula 3;

[0026]

[0027] Wherein, N Po (t 1 ) is the pumping time t 1 The number of 218 Po on the filter paper at the cut-off, t 1 is the pumping time, and d is the differential symbol;

[0028] Solve formula 3 to obtain formula 4;

[0029]

[0030] Wherein, e is the base of the natural logarithm;

[0031] According to formula 4, as the pumping time t 1 increases, the number of 218 Po on the filter paper tends to be stable;

[0032] III. When the pumping time t 1 ends, there is no new 218 Po accumulating on the filter paper, 218 and the 218 Po on the filter paper will only continue to decay. At this time, the decay law of 2 Po on the filter paper with the measurement time t is shown in formula 5;

[0033]

[0034] Wherein, N Po (t 2 ) is the number of 2 Po on the filter paper at the cut-off of the measurement time t 218 , t 2 is the measurement time, and the starting moment of the measurement time is the cut-off moment of the pumping time;

[0035] IV. When the pumping time t 1 ends, the number of radiation response signals generated by the CMOS image sensor excited by α particles is proportional to the number of α particles emitted by the decay of 218 Po on the filter paper. The relationship between the two is shown in formula 6;

[0036]

[0037] Wherein, N α is the number of α particles detected by the CMOS image sensor (i.e., the number of radiation response signals generated by being excited by α particles) after the pumping time t 1 ends, η is the detection efficiency of the CMOS image sensor, and d is the differential symbol;

[0038] Ⅴ. Substitute Equation 5 into Equation 6 to obtain Equation 7;

[0039]

[0040] In the formula, d is the differential symbol;

[0041] Integrate Equation 7 to obtain Equation 8;

[0042]

[0043] Simultaneously solve Equation 4 and Equation 8 to obtain Equation 9;

[0044]

[0045] Substitute Equation 1 into Equation 9 and transform the obtained formula to obtain the radon concentration solving formula, that is, Equation 10;

[0046] Equation 10;

[0047]

[0048] The technical solution of the present invention is: a method for collecting data for determining the geological structure of a slope, based on the above-mentioned radon concentration measuring device in an open environment; characterized in that: the radon concentration measuring device in an open environment is one of the components of the data collection system for determining the geological structure of a slope; the data collection system for determining the geological structure of a slope further includes a surface connection device and a pipeline connection assembly;

[0049] The surface connection device includes a collection chamber and an intake pipe; the collection chamber is a hollow pipe, the lower end opening of which is open, the upper end opening of which is closed, a collection cavity is provided inside the collection chamber, a filter screen is installed at the lower end opening of the collection chamber, and a pipe passing hole is provided on the upper end surface of the collection chamber; the lower end of the intake pipe passes through the pipe passing hole and extends into the collection cavity, and the upper end is located outside the collection chamber; multiple sets of the surface connection device and the radon concentration measuring device are provided, and the surface connection device and the radon concentration measuring device are in one-to-one correspondence; the upper port of the intake pipe of the surface connection device is communicated with the intake port of the housing of the corresponding radon concentration measuring device;

[0050] The pipeline connection assembly includes an exhaust pipe and a collecting pipe; the number of exhaust pipes is the same as the number of sets of the radon concentration measuring device, the exhaust pipes and the radon concentration measuring device are in one-to-one correspondence, and the front end of the exhaust pipe is connected to the exhaust port of the housing of the corresponding radon concentration measuring device; the collecting pipe is a pipe with one end closed and the other end open, multiple shunt ports are provided at intervals along the length direction of the pipe body of the collecting pipe, the number of shunt ports is the same as the number of exhaust pipes, the shunt ports and the exhaust pipes are in one-to-one correspondence, the shunt ports are connected to the rear ends of the corresponding exhaust pipes, and the open end of the collecting pipe is connected to the intake end of the air pump;

[0051] The steps of the collection method are as follows:

[0052] S01. Arranging a data acquisition network: Installing the surface connection devices on the slope surface of the slope in a rectangular dot matrix pattern, inserting the lower end of the acquisition chamber into the soil below the slope surface, and using the filter screen at the lower end pipe orifice of the acquisition chamber to prevent soil or other sundries from being sucked into the acquisition cavity and to allow the air in the soil pores to penetrate into the acquisition cavity; Connecting all the surface connection devices to the corresponding radon concentration measuring devices respectively, and connecting the pipeline connection assembly to all the radon concentration measuring devices; Connecting the air pump to the pipeline connection assembly; Thus, the arrangement of the data acquisition network is completed;

[0053] S02. Air extraction at each measuring point: After starting the air pump, the air in the soil pores penetrates through the filter screen at the lower end of the acquisition chamber into the acquisition cavity, and then successively passes through the intake pipe - intake port - gas path channel - filter paper - exhaust port - outlet pipe - manifold - air pump and is discharged into the atmosphere;

[0054] In this step, control the air flow rate passing through the filter paper in each radon concentration measuring device to be consistent, so that in the subsequent steps, the data obtained from each measuring point in the data acquisition network can be horizontally compared and aggregated for calculation;

[0055] S03. Obtaining a frame image: During the above air flow process, the radioactive aerosol containing radon daughters is intercepted on the filter paper, and the air containing radon gas can continue to flow through the filter paper; The α particles generated by the decay of the radon daughters on the filter paper pass through the light-shielding film and hit the surface of the CMOS image sensor, causing the CMOS image sensor to generate a radiation response signal; The SOC chip collects and processes the output data of the CMOS image sensor and converts it into a continuous frame image and transmits it to the PC; The frame image is the data for determining the geological structure of the slope.

[0056] A further technical solution of the present invention is: In step S03, the number of radiation response signals in the frame image is positively correlated with the number of radon daughters on the filter paper, and the number of radon daughters on the filter paper is positively correlated with the radon concentration in the soil. Therefore, the number of radiation response signals in the frame image is positively correlated with the radon concentration in the soil. Counting the number of radiation response signals in the frame image can be used to determine whether there is a landslide body on the slope and to determine the scope and scale of the landslide body.

[0057] The present invention has the following advantages compared with the prior art:

[0058] 1. Its structure is simple, small in size and easy to carry. Compared with the radon concentration measuring device in the background technology, it has been improved from the technical route level, selects different measuring media (radioactive aerosol), and correspondingly designs the collection structure of the measuring media, and is applicable to the measurement of air radon concentration in an open environment (outdoor environment).

[0059] 2. It uses the method of physical adsorption to collect the measurement medium (radioactive aerosol), that is, it uses an air pump to drive the flow of the air path defined by the air to be measured, and sets the filter paper used to intercept the radioactive aerosol in the air path, so that the measurement medium can be collected efficiently, without omission, stably and reliably. The subsequent processes of exciting and statistically analyzing the radiation response signals will not be commented on here; compared with the radon concentration measurement device in the background technology, its measurement efficiency, stability and reliability have been improved.

[0060] 3. There is no need to evaporate a metal thin layer on the photosensitive surface of the core component CMOS image sensor, nor is it necessary to apply a high voltage to establish a high-voltage electrostatic field on the CMOS image sensor. The measurement medium is collected on the filter paper and will not contaminate the CMOS image sensor, which greatly extends the service life of the CMOS image sensor; on the premise of not considering the radiation damage of the CMOS image sensor, it is only necessary to replace the new filter paper before each measurement start (equivalent to only the filter paper being the consumable), and compared with the radon concentration measurement device in the background technology, the measurement cost is greatly reduced.

[0061] 4. It uses the method of physical adsorption to collect radioactive aerosol. Compared with the existing radon concentration measurement devices based on electrostatic adsorption method and CMOS image sensor, there is no need to establish a high-voltage electrostatic field near the CMOS image sensor, so there is no problem of affecting the stability of radon concentration measurement due to current noise, thus improving the stability of radon concentration measurement.

[0062] 5. It has the characteristics of simple structure, small size, portability and easy assembly. It can be used to assemble a data acquisition system for determining the boundary of slope landslides, and then realize the collection of radon gas data in a rectangular dot matrix pattern on the slope surface of the slope. Each point in the rectangular dot matrix can achieve synchronous collection, and the radon gas data of each point are horizontally compared and summarized for calculation, which can be used as reference data for analyzing the fracture system of geological bodies and determining the boundary of slope landslides. Description of the Drawings

[0063] Figure 1 It is the assembly drawing of the radon gas measurement device in the present invention;

[0064] Figure 2 It is the explosion drawing of the radon gas measurement device in the present invention;

[0065] Figure 3 It is the electrical connection relationship diagram of each component in the radon gas measurement device;

[0066] Figure 4 It is the structural schematic diagram of the data acquisition system for determining the slope geological structure;

[0067] Figure 5 It is the internal cross-sectional view of the surface connection device in the data acquisition system for determining the slope geological structure.

[0068] Special note: Figure 1-2 In, the air pump and the PC are both omitted and not drawn. Figure 4 In, the PC is omitted and not drawn. Figure 4 In, the arrangement of the rectangular dot matrix is relatively dense for intuitive display, and the actual on-site installation density can be adjusted as required.

[0069] Legend: housing 11; gas path channel 111; air inlet 112; mounting port 113; exhaust port 114; filter paper 12; clip 13; outer shell 21; light-shielding film 22; circuit board 23; CMOS image sensor 231; chip board 24; SoC chip 241; air pump 3; PC 4; collection chamber 51; collection cavity 511; filter screen 512; intake pipe 52; outlet pipe 61; manifold pipe 62; shunt port 621. Specific implementation mode

[0070] Embodiment 1:

[0071] As Figure 1-3 shown, the radon concentration measuring device includes a daughter nuclide collection component, an induction processing component, an air pump 3 and a PC 4.

[0072] The daughter nuclide collection component includes a housing 11 and a filter paper 12. The housing 11 is a split structure. Inside the housing 11, there is a gas path channel 111 arranged in a T shape. One end of the gas path channel 111 forms an air inlet 112 on the surface of the housing 11, and the other end of the gas path channel 111 forms a mounting port 113 and an exhaust port 114 arranged opposite to each other on the surface of the housing 11. The filter paper 12 is detachably installed inside the gas path channel 111 of the housing 11.

[0073] The induction processing component includes an outer shell 21, a light-shielding film 22, a circuit board 23 and a chip board 24. One end of the outer shell 21 is a docking end. Inside the outer shell 21, there is a component cavity. On the end face of the docking end of the outer shell 21, there is a radiation hole. The light-shielding film 22 is covered and installed on the radiation hole of the outer shell 21. The outer shell 21 is hermetically inserted into the mounting port 113 of the housing 11 through the docking end, so that the light-shielding film 22 and the filter paper 12 are arranged opposite to each other without any obstacles in between. The circuit board 23 and the chip board 24 are both installed in the component cavity of the outer shell. A CMOS image sensor 231 is installed on the circuit board 23. The surface of the CMOS image sensor 231 is not glass-encapsulated so that the photosensitive surface is exposed. The photosensitive surface of the CMOS image sensor 231 and the light-shielding film 22 are arranged opposite to each other without any obstacles in between. An SoC chip 241 is installed on the chip board 24. The chip board 24 is communicatively connected to the circuit board 23. The chip board 24 is used to output a frame image containing a radiation response signal.

[0074] The intake end of the air pump 3 is communicated with the exhaust port 114 of the housing through a pipeline, and the exhaust end of the air pump 3 is communicated with the atmosphere.

[0075] The PC 4 is communicatively connected to the chip board 24, and is used to adjust the parameters of the CMOS image sensor 231, and store and process the frame image containing the radiation response signal output by the chip board, specifically, to count the radiation response signal in the frame image and calculate the radon concentration based on it.

[0076] Preferably, the distance between the photosensitive surface of the CMOS image sensor 231 and the surface of the filter paper 12 facing the CMOS image sensor 231 is less than 5 mm.

[0077] Preferably, the housing 11 and the shell 21 are both made of light-proof and radiation-shielding materials, and the light-shielding film 22 is made of light-proof and radiation-permeable materials.

[0078] Preferably, the sub-body collection assembly further includes a clip 13. The clip 13 is made of a light-proof and radiation-shielding material, and is installed inside the gas path 111 of the housing 11. The clip 13 is formed by two sub-pieces buckled together, and each sub-piece has a hollow hole at its center. The filter paper 12 is clamped and fixed between the two sub-pieces of the clip 13 to cover the hollow holes of the two sub-pieces.

[0079] Briefly describe the working principle of the present invention:

[0080] A method for measuring gas radon concentration is based on the above-mentioned radon concentration measuring device. Before executing the measuring method, parameter control software is installed on a PC. The parameter control software is used to call the register address of a CMOS image sensor and assign a value to adjust the gain and integration time of the CMOS image sensor. The integration time of the CMOS image sensor is set to 0.001-1s and the gain is set to between 1-100dB on a PS machine through the parameter control software.

[0081] Here are the steps:

[0082] The radon concentration measuring device in an open environment is placed in the environment to be tested, and the air pump is started to make the air to be tested flow at a constant flow rate along the path of air inlet 112-air channel 111-filter paper 12-air channel 111-exhaust port 114-air pump 6-external environment. During the flow of the air to be tested, the radioactive aerosol containing radon progeny is trapped on the filter paper 12, and the air and gaseous radon can continue to flow through the filter paper 12; the alpha particles generated by the decay of the radon progeny on the filter paper 12 pass through the light shielding film 22 and hit the surface of the CMOS image sensor 231, so that the CMOS image sensor 231 generates a radiation response signal; the chip board 24 collects and processes the output data of the CMOS image sensor 231 and converts it into a continuous frame image and transmits it to the PC 25; the PC 25 counts the radiation response signals in the frame image and uses this as a basis to estimate the radon concentration.

[0083] The process of estimating radon concentration based on the radiation response signal is as follows:

[0084] Ⅰ. In air, when 222 Rn and 218 Po reach decay equilibrium, 218 the concentration of 222 Po is proportional to the concentration of

[0085]

[0086] Rn. The relationship between them is shown in Formula 1; Po In the formula, C 218 is the concentration of Rn Po, λ 222 is the decay constant of Po Rn, λ 218 is the decay constant of Rn Po, and C 222 is the concentration of 218 Rn; during the air extraction process after starting the air pump, the number of Po Po intercepted by the filter paper per unit time is shown in Formula 2; Formula 2: V Po = C Po ·Q; in the formula, V 218 is the number of 218 Po intercepted by the filter paper per unit time, is the number of

[0087] Po contained in the gas per unit volume, and Q is the air extraction flow rate. 218 Ⅱ. During the air extraction process after starting the air pump, the 218 Po on the filter paper gradually accumulates and decays simultaneously. The accumulation and decay of

[0088]

[0089] Po are represented by a differential equation, as shown in Formula 3; Po (t 1 ) is the number of 1 Po on the filter paper at the end of the air extraction time t 218 , t 1 is the air extraction time, and d is the differential symbol;

[0090] Solving Formula 3 gives Formula 4;

[0091]

[0092] In the formula, e is the base of the natural logarithm;

[0093] According to Formula 4, as the air extraction time t 1 increases, the number of 218 Po on the filter paper tends to be stable.

[0094] Ⅲ. When the pumping time t 1 ends, there is no new 218 Po accumulation on the filter paper, 218 and Po will only continue to decay. At this time, the 218 Po on the filter paper decays according to the decay law of the measurement time t 2 as shown in Formula 5;

[0095]

[0096] In the formula, N Po (t 2 ) is the quantity of Po on the filter paper when the measurement time t 2 ends. t 218 is the measurement time, and the starting moment of the measurement time is the ending moment of the pumping time. 2

[0097] Ⅳ. When the pumping time t 1 ends, the number of radiation response signals generated by the CMOS image sensor excited by α particles is proportional to the number of α particles emitted by the decay of 218 Po on the filter paper. The relationship between the two is shown in Formula 6;

[0098]

[0099] In the formula, N α is the number of α particles detected by the CMOS image sensor after the pumping time t 1 ends (i.e., the number of radiation response signals generated by the excitation of α particles), η is the detection efficiency of the CMOS image sensor, and d is the differential symbol.

[0100] Ⅴ. Substitute Formula 5 into Formula 6 to obtain Formula 7;

[0101]

[0102] In the formula, d is the differential symbol;

[0103] Integrate Formula 7 to obtain Formula 8;

[0104]

[0105] Combine Formula 4 and Formula 8 to obtain Formula 9;

[0106]

[0107] Substitute Formula 1 into Formula 9 and transform the obtained formula to get the radon concentration solution formula, that is,

[0108] Formula 10;

[0109]

[0110] Briefly describe the application scenarios of the present invention:

[0111] In many engineering practices, especially in the construction of facilities such as hydropower and highways in mountainous areas, various slope problems are often encountered. One of them is that some ancient landslides existing around the engineering site are found through on-site exploration. The deformation characteristics of these landslides are obvious, but it is very difficult to determine some boundaries only based on surface investigation.

[0112] Generally, in structures with good openness and high connectivity of the structure, it is conducive to the enrichment of radon gas. As long as there is a covering layer with a certain thickness on the surface layer of the fracture system, most of the radon gas can be enriched and retained. Therefore, measuring the radon gas concentration (or relative concentration) can indirectly reflect the situation of the fracture system of the geological body, and its openness and degree of fragmentation can be analyzed. The radon gas concentration (or relative concentration) can be mutually verified with the results of on-site investigation, which is helpful for the stability analysis of slopes during bank slope excavation and provides a scientific basis for the safe construction of the project.

[0113] Such as Figure 4-5 shown, the slope geological structure determination data acquisition system is based on the above-mentioned radon concentration measurement device. It also includes a surface connection device and a pipeline connection component.

[0114] The surface connection device includes a collection chamber 51 and an intake pipe 52; the collection chamber 51 is a hollow pipe with an open lower end and a closed upper end. There is a collection cavity 511 inside the collection chamber 51. A filter screen 512 is installed at the lower end opening of the collection chamber 51, and a pipe hole is provided on the upper end surface of the collection chamber 51. The lower end of the intake pipe 52 passes through the pipe hole and extends into the collection cavity 511, and the upper end is located outside the collection chamber 51. There are multiple sets of the surface connection device and the radon concentration measurement device, and the surface connection device corresponds to the radon concentration measurement device one by one; the upper port of the intake pipe 52 of the surface connection device is communicated with the air inlet 112 of the housing of the corresponding radon concentration measurement device.

[0115] The pipeline connection component includes an exhaust pipe 61 and a collecting pipe 62; the number of exhaust pipes 61 is the same as the number of sets of the radon concentration measurement device, and the exhaust pipes 61 correspond to the radon concentration measurement device one by one. The front end of the exhaust pipe 61 is connected to the exhaust port 114 of the housing of the corresponding radon concentration measurement device; the collecting pipe 62 is a pipe with one end closed and the other end open. A plurality of shunt ports 621 are provided at intervals along the length direction of the pipe body of the collecting pipe 62. The number of shunt ports 621 is the same as the number of exhaust pipes 61, and the shunt ports 621 correspond to the exhaust pipes 61 one by one. The shunt ports 621 are connected to the rear ends of the corresponding exhaust pipes 61, and the open end of the collecting pipe 62 is connected to the intake end of the air pump 3.

[0116] Method for collecting data for determining slope geological structure, based on the above-mentioned data collection system for determining slope geological structure, where the geological structure includes whether there is a landslide body on the slope, as well as the scope and scale of the landslide body.

[0117] The method steps are as follows:

[0118] S01. Arrange the data collection network: Install the surface connection devices in a rectangular dot matrix pattern on the slope surface of the slope. The lower end of the collection chamber 51 is inserted into the soil below the slope surface. The filter screen 512 at the lower end pipe orifice of the collection chamber 51 is used to prevent soil or other sundries from being sucked into the collection cavity 511, and to allow air in the soil gaps to penetrate into the collection cavity 511; Connect all the surface connection devices to the corresponding radon concentration measurement devices respectively, and the pipeline connection assembly is connected to all the radon concentration measurement devices; Connect the air pump to the pipeline connection assembly; thus, the arrangement of the data collection network is completed.

[0119] S02. Pump air at each measuring point: After starting the air pump 3, the air in the soil gaps penetrates through the filter screen 512 at the lower end of the collection chamber 51 into the collection cavity 511, and then successively passes through the intake pipe 52 - intake port 112 - air passage 111 - filter paper 12 - exhaust port 114 - outlet pipe 61 - manifold 62 - air pump 3, and is discharged into the atmosphere.

[0120] In this step, control the air flow rate passing through the filter paper 12 in each radon concentration measurement device to be consistent, so that in the subsequent steps, the data obtained at each measuring point in the data collection network can be horizontally compared and summarized for calculation.

[0121] S03. Obtain frame images: During the above air flow process, the radioactive aerosol containing radon daughters is intercepted on the filter paper 12, and the air containing radon gas can continue to flow through the filter paper 12; The α particles generated by the decay of the radon daughters on the filter paper 12 pass through the light-shielding film and hit the surface of the CMOS image sensor 231, causing the CMOS image sensor 231 to generate a radiation response signal; The SOC chip collects and processes the output data of the CMOS image sensor and converts it into a continuous frame image and transmits it to the PC; The frame image is the data for determining the slope geological structure.

[0122] In this step, the number of radiation response signals in the frame image is positively correlated with the number of radon daughters on the filter paper, and the number of radon daughters on the filter paper is positively correlated with the radon concentration in the soil. Therefore, the number of radiation response signals in the frame image is positively correlated with the radon concentration in the soil.

[0123] In the descriptions of the above-mentioned data collection system for determining slope geological structure and the method, the "radon concentration measurement device" is the abbreviation of the "radon concentration measurement device in an open environment".

[0124] Known: 1. The radon concentration surges at the location of the landslide mass on the slope, which can reach dozens to hundreds of times the radon concentration in the area without the landslide mass; 2. When the radon in the soil reaches decay equilibrium, there is a fixed proportional relationship between the radon concentration in the soil and the number of radon progeny on the filter paper; 3. The number of radon progeny on the filter paper is linearly positively correlated with the number of radiation response signals excited by the radon progeny. Therefore, by counting the number of radiation response signals in the frame image, it can be used to determine whether there is a landslide mass on the slope, as well as to determine the scope and scale of the landslide mass.

Claims

1. A radon concentration measuring device in an open environment, characterized by: It includes a sub-body collection component and an induction processing component; The sub-body collection assembly includes a shell and filter paper; the shell is an integrated or split structure, and a T-shaped air passage is provided inside the shell, one end of the air passage forms an air inlet on the shell surface, and the other end of the air passage forms a mounting port and an exhaust port arranged oppositely on the shell surface; the filter paper is detachably installed inside the air passage of the shell; The induction processing component includes a shell, a light shielding film, a circuit board and a chip board; one end of the shell is a butt end, a component cavity is arranged inside the shell, and a ray hole is arranged on the end surface of the butt end of the shell; the light shielding film is covered and installed on the ray hole of the shell; the shell is sealed and inserted into the installation opening of the shell through the butt end, so that the light shielding film and the filter paper are arranged directly opposite to each other without any obstruction; The circuit board and the chip board are both installed in the component cavity of the housing. A CMOS image sensor is installed on the circuit board. The surface of the CMOS image sensor is not glass-encapsulated so that the photosensitive surface is exposed. The photosensitive surface of the CMOS image sensor and the light-shielding film are arranged opposite to each other without any shielding objects. A SoC chip is installed on the chip board, and the chip board is communicatively connected with the circuit board.

2. The radon concentration measuring device in an open environment as claimed in claim 1, characterized in that: It also includes an air pump and a PC; the air inlet end of the air pump is connected to the exhaust port of the shell through a pipeline, and the exhaust end of the air pump is connected to the atmosphere; the PC is communicated with the chip board, and the PC is used to store and process the frame image containing the radiation response signal output by the chip board.

3. The radon concentration measuring device in an open environment as claimed in claim 2, characterized in that: The distance between the photosensitive surface of the CMOS image sensor and the surface of the filter paper facing the CMOS image sensor is less than 5 mm.

4. The radon concentration measuring device in an open environment as claimed in claim 3, characterized in that: The shell and the outer shell are both made of light-proof and radiation-shielding materials, and the light-shielding film is made of light-proof and radiation-permeable materials.

5. The radon concentration measuring device in an open environment as claimed in claim 4, characterized in that: The sub-body collection component also includes a clip; the clip is made of an opaque and radiation-shielding material, the clip is installed inside the air path of the shell, the clip is composed of two sub-pieces that are interlocked with each other, and each sub-piece has a hollow hole at the center. The filter paper is clamped and fixed between the two sub-pieces of the clip and covers the hollow holes of the two sub-pieces.

6. A method for measuring radon concentration in air, based on the radon concentration measuring device in an open environment according to any one of claims 1 to 5, characterized in that: Before executing the measurement method, parameter control software is installed on the PC. The parameter control software is used to call the register address of the CMOS image sensor and assign values ​​to adjust the gain and integration time of the CMOS image sensor. The integration time of the CMOS image sensor is set to 0.001-1s and the gain is set to between 1-100dB on the PS machine through the parameter control software. Here are the steps: A radon concentration measuring device in an open environment is placed in an environment to be tested, and an air pump is started to make the air to be tested flow at a constant flow rate along the path of air inlet-air channel-filter paper-air channel-exhaust port-air pump-external environment. During the flow of the air to be tested, radioactive aerosols containing radon progeny are retained on the filter paper, while air and gaseous radon can continue to flow through the filter paper; alpha particles generated by the decay of radon progeny on the filter paper pass through the light shielding film and hit the surface of the CMOS image sensor, so that the CMOS image sensor generates a radiation response signal; The chip board collects and processes the output data of the CMOS image sensor and converts it into continuous frame images and transmits it to the PC; the PC counts the radiation response signals in the frame images and uses this as a basis to estimate the radon concentration.

7. The method for measuring radon concentration in gas as claimed in claim 6, characterized in that: The process of estimating radon concentration based on the radiation response signal is as follows: Ⅰ. In the air, when 222 Rn and 218 When Po reaches decay equilibrium, 218 The concentration of Po and 222 The concentration of Rn is proportional to the concentration of Rn. The relationship between the two is shown in Formula 1; Formula 1: In the formula, C Po for 218 Concentration of Po, λ Rn for 222 Decay constant of Rn, λ Po for 218 Decay constant of Po, C Rn for 222 The concentration of Rn; during the air extraction process after the air pump is started, the filter paper intercepts 218 The number of Po, see formula 2; Formula 2: V Po =C Po ·Q; where V Po The amount of water retained by the filter paper per unit time 218 The number of Po is the amount of 218 Po is the number, Q is the air extraction flow rate; Ⅱ. During the air extraction process after starting the air pump, the 218 Po gradually accumulates and decays at the same time, 218 The accumulation and decay of Po are expressed by differential equations, see formula 3; Formula 3: Where N Po (t1) is the pressure on the filter paper at the end of the vacuum time t1. 218 Po is the number, t1 is the pumping time, and d is the differential sign; Solve formula 3 to obtain formula 4; Formula 4: In the formula, e is the base of natural logarithm; According to formula 4, as the air extraction time t1 increases, the 218 The number of Po tends to be stable; Ⅲ. When the air extraction time t1 ends, there is no new 218 Po accumulation, 218 Po will only continue to decay, at this time, the filter paper 218 The decay law of Po with the measurement time t2 is shown in formula 5; Formula 5: Where N Po (t2) is the number of 218Po on the filter paper at the end of the measurement time t2, t2 is the measurement time, and the starting time of the measurement time is the end time of the air extraction time; IV. When the air extraction time t1 is terminated, the number of radiation response signals generated by the CMOS image sensor stimulated by α particles and the number of radiation response signals on the filter paper 218 The number of α particles emitted by Po decay is proportional to the number of α particles emitted by Po decay. The relationship between the two is shown in Formula 6; Formula 6: Where N α is the number of α particles detected by the CMOS image sensor after the exhaust time t1 is terminated (i.e., the number of radiation response signals generated by the α particles), η is the detection efficiency of the CMOS image sensor, and d is the differential sign; V. Substitute Formula 5 into Formula 6 to obtain Formula 7; Formula 7: In the formula, d is the differential symbol; After integrating formula 7, we get formula 8; Formula 8: Combining Formula 4 and Formula 8, we can get Formula 9; Formula 9: Substitute formula 1 into formula 9 and transform the resulting formula to obtain the formula for solving radon concentration, which is formula 10; Formula 10:

8. A method for collecting data for determining the geological structure of a slope, based on the radon concentration measuring device in an open environment as claimed in claim 5; characterized in that: The radon concentration measuring device in an open environment is one of the components of the slope geological structure determination data acquisition system; the slope geological structure determination data acquisition system also includes a surface connection device and a pipeline connection component; The surface connection device includes a collection chamber and an air inlet pipe; the collection chamber is a hollow pipe, the lower end of which is open and the upper end is closed, a collection cavity is provided inside the collection chamber, a filter is installed at the lower end of the collection chamber, and a pipe hole is provided on the upper end surface of the collection chamber; the lower end of the air inlet pipe passes through the pipe hole and extends into the collection cavity, and the upper end is located outside the collection chamber; the surface connection device and the radon concentration measuring device are both provided with multiple sets, and the surface connection device corresponds to the radon concentration measuring device one by one; the upper port of the air inlet pipe of the surface connection device is connected to the air inlet of the shell of the corresponding radon concentration measuring device; The pipeline connection assembly includes an air outlet pipe and a collection pipe; the number of the air outlet pipes is consistent with the number of sets of radon concentration measuring devices, the air outlet pipes correspond to the radon concentration measuring devices one by one, and the front end of the air outlet pipe is connected to the exhaust port of the shell of the corresponding radon concentration measuring device; the collection pipe is a pipe with one end closed and the other end open, and the collection pipe is provided with a plurality of diversion ports at intervals along the length direction of the pipe body, the number of the diversion ports is consistent with the number of the air outlet pipes, the diversion ports correspond to the air outlet pipes one by one, the diversion ports are connected to the rear ends of the corresponding air outlet pipes, and the open end of the collection pipe is connected to the air inlet end of the air pump; The steps are as follows: S01. Arrange the data acquisition network: install the surface connection device on the slope surface in a rectangular lattice pattern, insert the lower end of the collection chamber into the soil below the slope surface, and the filter at the pipe opening at the lower end of the collection chamber is used to prevent soil or other debris from being sucked into the collection chamber, and to allow air in the soil gap to penetrate into the collection chamber; connect all the surface connection devices to the corresponding radon concentration measuring devices respectively, and connect the pipeline connection assembly to all the radon concentration measuring devices; connect the air pump to the pipeline connection assembly; and complete the arrangement of the data acquisition network; S02. Air extraction at each measuring point: After the air pump is started, the air in the soil gap enters the collection chamber through the filter at the lower end of the collection chamber, and then passes through the air inlet pipe-air inlet-air channel-filter paper-exhaust port-air outlet pipe-collecting pipe-air pump in sequence and is discharged into the atmosphere; In this step, the air flow rate passing through the filter paper in each radon concentration measuring device is controlled to be consistent, so that in the subsequent steps, the data obtained by each measuring point in the data acquisition network can be horizontally compared and summarized; S03. Acquire frame images: During the above-mentioned air flow process, radioactive aerosols containing radon progeny are retained on the filter paper, while air containing radon gas can continue to flow through the filter paper; α particles generated by the decay of radon progeny on the filter paper pass through the light-shielding film and hit the surface of the CMOS image sensor, causing the CMOS image sensor to generate a radiation response signal; the SOC chip collects and processes the output data of the CMOS image sensor and converts it into continuous frame images and transmits it to the PC; the frame images are the data used to determine the geological structure of the slope.

9. The method for collecting data for determining the geological structure of a slope according to claim 8, characterized in that: In step S03, the number of radiation response signals in the frame image is positively correlated with the number of radon progeny on the filter paper, and the number of radon progeny on the filter paper is positively correlated with the radon concentration in the soil. Therefore, the number of radiation response signals in the frame image is positively correlated with the radon concentration in the soil. Counting the number of radiation response signals in the frame image can be used to determine whether there is a landslide body on the slope and to determine the scope and scale of the landslide body.

Images