An apparatus and method for enrichment and desorption of extremely low radon concentrations.

Abstract

This invention belongs to the field of radon concentration measurement technology, specifically disclosing an apparatus and method for enrichment and analysis of extremely low radon concentrations. The apparatus includes a vertically placed cylinder with a heating device and a pressurizing device mounted on it. A radon escapement structure, made of activated carbon fiber, is housed inside the cylinder. A negative pressure pump is located at the outlet end of the radon escapement structure, providing a negative pressure environment to guide airflow. The outlet end of the negative pressure pump is connected to a distributor. The first path of the distributor is open to the atmosphere, used to discharge the treated air during the radon collection stage of the radon escapement structure. The end of the second path is connected to a radon detection instrument for radon concentration measurement during the radon release stage of the radon escapement structure. This invention lowers the detection limit of radon concentration measurement, solving the problem that radon concentrations in certain environments are below the detection limit of radon measuring equipment, thus making measurement impossible. This provides support for effectively assessing the impact of environmental radiation background on extremely low background physics experiments.

Description

Technical Field

[0001] This invention belongs to the field of radon concentration measurement technology, and relates to an apparatus and method for enrichment and analysis of extremely low radon concentrations. Background Technology

[0002] Radon is a monatomic inert gas, colorless and odorless, soluble in water, blood, fat, and many other liquids. It is chemically inert, existing as free atoms in the air, and decays to produce a series of new nuclides, known as radon progeny. Both radon and its progeny are solid and radioactive, which may affect the accuracy of experimental results. Therefore, stricter control standards are required for radon in laboratory settings.

[0003] Deep underground or in areas far from radioactive mineral deposits, the soil and rocks contain fewer radioactive elements, resulting in very low radon release levels, which is highly advantageous for certain experiments. For example, the Jinping Underground Laboratory in China, located in the Jinping Mountain Tunnel on the banks of the Yalong River in Liangshan Prefecture, Sichuan Province, has a vertical rock cover thickness of up to 2400 meters, greatly reducing the impact of cosmic rays. Furthermore, the underground laboratory employs a "waterproof and radon-suppressing" technology, using a complex 10-layer structure to create a "protective shield" for the laboratory. This multi-layered structure effectively blocks water and radon gas from entering the rock, providing a low-radon environment for certain experiments.

[0004] Typically, the environmental level needs to be reassessed before conducting an experiment. However, in environments with extremely low radon concentrations, the concentration is below the detection limit of the radon measuring equipment, making it impossible to measure accurately. This makes it difficult to accurately assess the impact of the environmental radiation background on the extremely low background physics experiment, thus making it difficult to guarantee the accuracy of the experiment. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus and method for enriching and analyzing extremely low radon concentrations. This method involves rapidly passing a large volume of air through a radon trapping structure, thereby capturing radon in the air. Once the collected radon exceeds the minimum detection limit of the device, the trapping structure releases the captured radon again. The resulting radon parameters are then determined by an instrument. This invention solves the technical problem of low radon concentrations in certain environments preventing instrument measurement and effectively lowers the detection limit for radon concentration measurements.

[0006] To achieve the above objectives, the present invention provides an apparatus and method for enrichment and analysis of extremely low radon concentrations, the specific technical solution of which is as follows:

[0007] An apparatus for enrichment and desorption of extremely low radon concentrations, comprising:

[0008] The cylinder is placed vertically and is equipped with a heating device and a pressurizing device to adjust the temperature and air pressure inside the cylinder, respectively.

[0009] A radon escapement structure is fitted inside the cylinder. The radon escapement structure has an inlet end and an outlet end. The inlet end is used to introduce air, and the outlet end is above the inlet end. The radon escapement structure is made of activated carbon fiber and includes a first cone, a second straight cylinder, and a second cone arranged sequentially from bottom to top and connected end to end. The second straight cylinder is provided with multiple airflow channels. Each airflow channel is provided with multiple diverting rods spaced apart along the length of the airflow channel. One end of each diverting rod is fixed to the hole wall of the airflow channel, and the other end is in a free-floating state / fixed to the hole wall of the airflow channel. There is an included angle α between two adjacent diverting rods, and the included angle α is between 30 degrees and 90 degrees.

[0010] A negative pressure pump, installed at the outlet end of the radon escapement structure, is used to provide a negative pressure environment inside the radon escapement structure to guide the airflow. The outlet end of the negative pressure pump is connected to a splitter that can split the air into two. The first passage of the splitter is connected to the atmosphere and is used to discharge the treated air during the radon collection stage of the radon escapement structure. The end of the second passage is connected to a radon detection instrument and is used to measure the radon concentration during the radon release stage of the radon escapement structure.

[0011] Preferably, the cross-section of the airflow channel is one of a regular hexagon, a square, a sector, or a circle, or any combination of two or three of the above structures.

[0012] Preferably, the cross-section of the diverter is circular, the diameter of the diverter is 0.25 to 0.28 times the maximum width of the cross-section of the airflow channel, and the distance from the center of the diverter to the end face of the second straight cylinder is 1.2 to 2 times the diameter of the diverter.

[0013] Preferably, the diameter of the diverter is 0.26 times the maximum width of the cross-section of the airflow channel, and the distance from the center of the diverter to the end face of the second straight cylinder is 1.5 times the diameter of the diverter.

[0014] Preferably, the cone angle of the first vertebra is greater than that of the second vertebra, and the length of the first vertebra is less than that of the second vertebra.

[0015] Preferably, the inlet end of the radon escapement structure is connected to one end of the first pipeline, and the other end of the first pipeline is vented to allow air to be introduced into the first pipeline. A first valve is provided on the first pipeline to control the on / off state of the first pipeline.

[0016] Preferably, the outlet end of the radon escapement structure is connected to one end of the second valve, the other end of the second valve is connected to the first port of the four-way valve, the second port of the four-way valve is connected to a pressure gauge, the third port of the four-way valve is connected to one end of the second pipeline, the fourth port of the four-way valve is connected to one end of the third valve, the other end of the third valve is vented for auxiliary exhaust, a negative pressure pump is installed on the second pipeline, a fourth valve is installed between the negative pressure pump and the four-way valve, the fourth valve is used to control the on / off state of the second pipeline, and a diverter is connected to the other end of the second pipeline.

[0017] Preferably, a fifth valve is provided on the first passage of the diverter to control the on / off state of the first passage of the diverter, and a sixth valve is provided on the second passage of the diverter to control the on / off state of the second passage of the diverter. The outlet end of the second passage is detachably connected to the radon detection instrument.

[0018] Preferably, a measuring component is provided on the first pipeline, the measuring component being used to measure the amount of air flowing through the first pipeline.

[0019] A method for measuring radon concentration in extremely low radon environments, based on the aforementioned apparatus for enrichment and analysis of extremely low radon concentrations, includes the following steps:

[0020] Open the first, second, fourth, and fifth valves, close the third and sixth valves, start the negative pressure pump, introduce air into the device, and use the radon escapement structure to capture radon in the air;

[0021] When the measuring component detects that the amount of air flowing through the first pipeline has reached the target volume of air, it closes the first valve and simultaneously closes the fifth valve and the negative pressure pump after a preset delay, thus ending the radon enrichment process.

[0022] Start the heating and pressurizing devices to pressurize and heat the inside of the cylinder. Once the preset value is reached, maintain it for a preset time.

[0023] Connect the radon detector to the outlet of the sixth valve, open the sixth valve and start the negative pressure pump, and use the radon detector to measure the radon concentration.

[0024] Compared with existing technologies, the present invention provides an apparatus and method for enrichment and analysis of extremely low radon concentrations. The apparatus allows a large volume of air to rapidly flow through a radon escapement structure, thereby capturing radon in the air. Once the radon collected on the escapement structure exceeds the minimum detection limit of the detection device, the captured radon is released again using the escapement structure. The radon parameters in the current air environment are then determined by instrument detection. This solves the technical problem of low radon concentrations in certain environments preventing instrument measurement, effectively lowering the detection limit for radon concentration measurement and addressing the issue of radon concentrations below the detection limit of radon measuring equipment in some environments. It provides support for effectively assessing the impact of environmental radiation background on extremely low background physics experiments, and provides a theoretical foundation and technical means for in-depth research on radon measurement principles and methods, as well as for research on new methods and technologies in radon monitoring and protection, and tracer applications. It has significant scientific and practical value, is highly applicable, and is worthy of promotion. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0026] Figure 2 This is a partial structural diagram of the present invention. Figure 1 .

[0027] Figure 3 This is a partial structural diagram of the present invention. Figure 2 .

[0028] Figure 4 This is a partial structural diagram of the present invention. Figure 3 .

[0029] Figure 5 This is a partial structural diagram of the present invention. Figure 4 . Detailed Implementation

[0030] Radon and its progeny are both solid and radioactive elements, which may affect the accuracy of experimental results. Therefore, stricter control standards are needed for radon in the laboratory. Typically, environmental levels need to be reassessed before conducting experiments. However, in environments with extremely low radon concentrations, the concentration is below the detection limit of radon measuring equipment, making accurate measurement impossible. This makes it difficult to accurately assess the impact of ambient radiation background on extremely low background physics experiments, thus compromising the accuracy of the experiments.

[0031] To address the technical problem that low radon concentrations in certain environments prevent instruments from measuring them, this invention provides a novel apparatus and method for enriching and analyzing extremely low radon concentrations.

[0032] To enable those skilled in the art to better understand and implement the technical solutions of this invention, the following will be described in conjunction with the appendix. Figure 1To the attached Figure 5 The technical solutions in this invention will be described clearly and in detail.

[0033] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0034] Furthermore, it should be further explained that in the description of the embodiments of the present invention, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present invention, "multiple" means two or more.

[0035] The terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first," "second," "third," or "fourth" may explicitly or implicitly include one or more of that feature, and in the description of this invention, unless otherwise stated, "multiple" means two or more.

[0036] Example 1

[0037] like Figures 1 to 5 As shown, this invention provides a device for enrichment and analysis of extremely low radon concentrations. The device structure includes a cylindrical body 1, which is vertically placed. The reason for the vertical placement of the cylindrical body 1 is that radon and its decay products have a higher specific gravity than air, but they possess a significant upward transport capacity. Essentially, the upward transport contribution of radon and its decay products is >45%, while the downward transport contribution is <45%. Furthermore, the longitudinal transport capacity of radon and its decay products is much greater than the lateral transport capacity, with the former >90% and the latter <10%. When the specific gravity of radon and its decay products is less than that of air, they can rise on their own. Therefore, radon and its decay products possess a much greater "buoyancy" capacity than diffusion and gravitational settling. Thus, the vertical design of the cylindrical body 1 facilitates the rapid separation of radon from the air. Simultaneously, the vertical placement conforms to the transport characteristics of radon, which is beneficial for improving the radon enrichment efficiency.

[0038] The cylinder 1 contains a radon escapement structure 2 installed in a nested manner. The radon escapement structure 2 has an inlet end and an outlet end, with the outlet end at the upper end and the inlet end at the lower end.

[0039] A first pipe is installed at the lower end of the cylinder 1. The first end of the first pipe is connected to the inlet end of the radon escapement structure 2, and the second end of the first pipe is vented, that is, connected to air, to introduce air into the first pipe. In addition, in order to facilitate the control of the on / off state of the first pipe, a first valve 5 is installed at the second end of the first pipe. When the first valve 5 is opened, air enters the radon escapement structure 2 inside the cylinder 1 through the first pipe. The radon in the air is captured by the radon escapement structure 2, and the remaining treated air flows out through the outlet end of the radon escapement structure 2.

[0040] The outlet end of the radon escapement structure 2 is connected to the inlet end of the second pipeline. The second pipeline is also connected to a negative pressure pump 3, which provides a negative pressure environment for the entire device, thereby causing air to enter the device through the first pipeline and then be discharged through the second pipeline. The outlet end of the second pipeline is connected to a splitter 4, which divides the pipeline into two paths. The first path is connected to the atmosphere as an exhaust port, through which the treated air is discharged. The exhaust port is equipped with a fifth valve 11, which is used to control the opening and closing state of the exhaust port. The second path is equipped with a sixth valve 12, the outlet end of which is connected to a radon detection instrument.

[0041] Furthermore, to facilitate control of the passage status and measurement, a four-way valve 7 is installed at the inlet end of the second pipeline. The first port of the four-way valve 7 is connected to the second valve 6, the other end of the second valve 6 is connected to the outlet end of the radon escapement structure 2, the second port of the four-way valve 7 is connected to a pressure gauge 8, the third port of the four-way valve 7 is connected to the inlet end of the second pipeline, the fourth port of the four-way valve 7 is connected to the first end of the third valve 9, and the second end of the third valve 9 is used for venting auxiliary exhaust.

[0042] In addition, a fourth valve 10 is provided between the four-way valve 7 and the negative pressure pump 3 to facilitate control of the passage status.

[0043] As a further refinement of an embodiment of the present invention, the radon escapement structure 2 is made of activated carbon fiber, such as... Figure 2 As shown, it includes a first cone 21, a second straight cylinder 22, and a second cone 23 arranged sequentially from bottom to top and connected end to end. The cone angle of the first cone 21 is greater than that of the second cone 23, and the length of the first cone 21 is less than that of the second cone 23. The large and short cone angle of the first cone 21 facilitates the rapid expansion and depressurization of air before it is introduced into the second straight cylinder 22, while the small and long cone angle of the second cone 23 facilitates the formation of the Laval effect, allowing the processed air to be pressurized and accelerated before being discharged.

[0044] To facilitate connection, a first straight cylinder is connected to the first vertebral body 21, which is used to connect to one end of the first pipeline. A third straight cylinder is connected to the second vertebral body 23, which is used to connect to one end of the second pipeline.

[0045] Activated carbon fiber is a new type of functional fiber made from organic fiber as a precursor through different pathways. As the third generation of new functional adsorbent material after powdered activated carbon and granular activated carbon, it has the characteristics of good formability, acid and alkali resistance, good electrical conductivity and chemical stability. It not only has a large specific surface area, moderate and uniform pore size distribution and fast adsorption speed, but also uses this material to prepare radon adsorption structures and attach a porous structure, which can effectively enhance its enrichment effect on radon.

[0046] Furthermore, as a further refinement of the embodiment of the present invention, in order to improve the radon adsorption capacity of the radon escapement structure 2, multiple airflow channels are provided on the second straight cylinder 22. The length direction of the airflow channels is consistent with the length direction of the second straight cylinder 22. The airflow channels form multiple paths for air circulation, increasing the contact opportunity between air and the wall of the airflow channels.

[0047] Furthermore, the cross-section of the airflow channel is one of the following: regular hexagon, square, sector, or circle, or any combination of two or three of the above structures.

[0048] Furthermore, as a further optimization of the embodiments of the present invention, the airflow channel has the best stress distribution and the best fabrication feasibility when its cross-section is circular.

[0049] Furthermore, as a further refinement of the embodiment of the present invention, in order to further increase the contact area between air and the radon escapement structure 2 and thus increase the adsorption capacity for radon, multiple diverting rods 24 are provided in each airflow channel, such as... Figure 3 As shown, multiple diverting rods 24 are spaced apart along the length of the airflow channel. The diverting rods 24 are located on the side of the second straight cylinder 22 near the first cone 21. One end of the diverting rod 24 is fixed to the hole wall of the airflow channel, and the other end is in a free suspended state.

[0050] Furthermore, as a further refinement of the embodiments of the present invention, such as Figures 3 to 5 As shown, there is an included angle α between two adjacent splitter bars 24, which is between 30 degrees and 90 degrees. This allows the direction of the Karman vortex street formed by the flow around the air after it passes through different splitter bars 24 to be misaligned. This prevents the vortex from accumulating at a fixed position on the wall and becoming saturated too early. Under the effect of misalignment, the adsorption on the wall can be made more uniform, which improves its enrichment capacity for radon.

[0051] Furthermore, as another optimization of the embodiment of the present invention, such as Figure 4As shown, both ends of the flow divider 24 can be fixed to the hole wall of the airflow channel.

[0052] Furthermore, as a further optimization of the embodiment of the present invention, the cross-section of the diverter 24 is circular, the distance from the center of the diverter 24 to the end face of the second straight cylinder 22 is 1.2 to 2 times the diameter of the diverter 24, the diameter of the diverter 24 is 0.25 to 0.28 times the maximum width of the cross-section of the airflow channel, and the distance between two adjacent diverter 24s is 6 to 8 times the diameter of the diverter 24.

[0053] Furthermore, as a further optimization of the embodiment of the present invention, the diameter of the diverter 24 is 0.26 times the maximum width of the cross-section of the airflow channel, the distance from the center position of the diverter 24 to the end face of the second straight cylinder 22 is 1.5 times the diameter of the diverter 24, and the distance between two adjacent diverter 24s is 7 times the diameter of the diverter 24. At this time, the connection effect of the multi-stage Karman vortex street formed after the adjacent diverter 24 is the best.

[0054] In use, radon-containing air enters the second straight cylinder 22 through the small end of the first cone 21, creating a pressure-reducing and flow-expanding effect. This lowers the air pressure and slows down the air velocity, which enhances the adsorption capacity of the second straight cylinder 22 upon entry. Simultaneously, as the air enters the airflow channel on the second straight cylinder 22, a flow-around effect is generated in the airflow channel behind the splitter bar 24 under the action of the splitter bar 24. This creates a multi-stage Karman vortex street within the airflow channel. Under the influence of the Karman vortex street, radon in the air is captured by the walls of the airflow channel after collisions. Due to the increased number of collisions between the airflow and the walls of the airflow channel, the radon... The increased contact probability with the wall surface leads to more radon being captured by the wall, thereby improving the radon capture efficiency of the radon escapement structure 2. As air flows from the second straight cylinder 22 through the second cone 23, the diameter of the second cone 23 decreases along the direction of air flow, thus forming a Laval tube structure. The air in this section generates a Laval nozzle effect, which increases the number of collisions between air particles. Due to the intense motion, the probability of collision with the wall surface of the second cone 23 increases, thus increasing the radon capture efficiency of the second cone 23. In addition, the Laval effect increases the air velocity in this section, which can also indirectly improve the detection efficiency.

[0055] Air enters from one end of the first pipeline, passes through the radon escapement structure 2, and is discharged from the exhaust port. The radon in the air is captured by the radon escapement structure 2, and the other treated air flows out through the outlet end of the radon escapement structure 2, thereby separating the radon in the air and storing it in the radon escapement structure 2.

[0056] In order to accurately define the volume of air passing through, a measuring component can also be installed on the first pipeline to measure the amount of air flowing through the first pipeline.

[0057] Specifically, the measuring component can be implemented using an airflow meter.

[0058] When radon capture is required, close the third valve 9 and the sixth valve 12, open the first valve 5, the second valve 6, the fourth valve 10 and the fifth valve 11, start the negative pressure pump 3, and introduce air into the device. Use the radon escapement structure 2 to capture radon in the air. When the measuring component confirms that the target volume of air has passed through, it sends a control command to the first valve 5 to close, and at the same time sends a control command to the fifth valve 11 and the negative pressure pump 3 to close after a 5-second delay. The purpose of the delay is to continue to discharge the air, and the enrichment process ends.

[0059] At this point, in order to accurately measure the radon concentration in the target volume of air, the radon captured on the radon escapement structure 2 can be released.

[0060] Furthermore, as a further refinement of the embodiment of the present invention, in order to improve the radon release efficiency of the radon escapement structure 2, a heating device is provided on the cylinder 1 to control the temperature inside the cylinder 1. The increase in the temperature inside the cylinder 1 will reduce the adsorption coefficient of the radon escapement structure 2, increase the activity of radon, thereby accelerating the rapid precipitation of radon and increasing the diffusion and movement speed of radon.

[0061] Specifically, the heating device includes a heating coil fitted onto the cylinder 1. The heating coil is electrically connected to the control box, which can adjust the temperature of the heating coil in real time, causing the temperature of the radon escapement structure 2 built into the cylinder 1 to change. The higher the temperature of the radon escapement structure 2, the lower its adsorption coefficient, and thus the higher the radon release rate. After heating for 5 to 10 minutes, and after the temperature of the heating coil rises to between 400°C and 450°C, the heating state is maintained for another 5 to 10 minutes to fully decompose the radon adsorbed by the radon escapement structure 2. The negative pressure pump 3 is used to extract the air inside the main body of the device from the outlet end of the sixth valve 12 and input it to the radon detection instrument for measurement.

[0062] Example 2

[0063] As a further improvement on the technical basis of the embodiment, in order to increase the radon release rate, a pressurization device is provided on the cylinder 1. The pressurization device is used to increase the air pressure inside the cylinder 1 to between 3 and 4 atmospheres. When the air pressure inside the cylinder 1 increases, the radon release rate is faster. Pressurization and heating can be carried out simultaneously to facilitate the rapid release of radon and improve the efficiency of the measurement.

[0064] Furthermore, the pressure gauge 8 installed on the device plays a safety protection role, used to measure the pressure at the outlet end of the radon escapement structure 2, and to prevent the pressure from exceeding the preset value during the pressurization process of the pressurization device, which could lead to safety hazards.

[0065] A method for measuring radon concentration in extremely low radon environments, based on the aforementioned apparatus for enrichment and analysis of extremely low radon concentrations, includes the following steps:

[0066] Open the first valve 5, the second valve 6, the fourth valve 10 and the fifth valve 11, close the third valve 9 and the sixth valve 12, start the negative pressure pump 3, introduce air into the device, and use the radon escapement structure 2 to capture radon in the air.

[0067] Once the measuring component detects that the amount of air flowing through the first pipeline has reached the target volume, it closes the first valve 5 and simultaneously closes the fifth valve 11 and the negative pressure pump 3 after a 5-second delay, thus ending the radon enrichment process.

[0068] At this point, the heating and pressurizing devices can be activated to pressurize and heat the inside of cylinder 1. When the temperature inside cylinder 1 is between 400°C and 450°C and the pressure inside cylinder 1 is between 3 and 4 atmospheres, maintain this pressure for 5 to 10 minutes. Then, connect the radon detection instrument to the outlet of the sixth valve 12, start the negative pressure pump 3, open the sixth valve 12, and use the radon detection instrument to measure the radon concentration.

[0069] It is worth noting that, for safety reasons, a protective structure can be added to the outside of the cylinder 1 to prevent the operator from being burned by the cylinder 1.

[0070] Specifically, the protective structure can be a cylindrical structure made of heat-insulating material, which can be fitted onto the cylinder 1.

[0071] As a further improvement on the technical basis of the embodiments, the insulation material can be one of glass fiber, asbestos, rock wool, silicate, aerogel felt or vacuum board.

[0072] The apparatus and method for enrichment and analysis of extremely low radon concentrations provided by this invention can be used to measure radon concentration in extremely low radon environments. This solves the problem that radon concentrations in some environments are below the detection limit of radon measuring equipment, making measurement impossible. It provides support for effectively assessing the impact of environmental radiation background on extremely low background physics experiments, and provides a theoretical basis and technical means for in-depth research on radon measurement principles and methods, as well as for research on new methods and technologies in radon monitoring and protection, tracer applications, etc. It has significant scientific significance and practical value.

[0073] It is understood that this invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this invention. Furthermore, under the teachings of this invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this invention. Therefore, this invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this invention are within the protection scope of this invention.

Claims

1. An apparatus for the enrichment and desorption of extremely low radon concentrations, characterized in that, include: The cylinder (1) is placed vertically. The cylinder (1) is equipped with a heating device and a pressurizing device, which are used to adjust the temperature and air pressure inside the cylinder (1) respectively. A radon escapement structure (2) is installed inside the cylinder (1). The radon escapement structure (2) has an inlet end and an outlet end. The inlet end is used to introduce air, and the outlet end is on the upper side of the inlet end. The radon escapement structure (2) is made of activated carbon fiber and includes a first cone (21), a second straight cylinder (22), and a second cone (23) arranged sequentially from bottom to top and connected end to end. The second straight cylinder (22) is provided with multiple airflow channels. Each airflow channel is provided with multiple diverting rods (24) spaced apart along the length of the airflow channel. One end of the diverting rod (24) is fixed to the hole wall of the airflow channel, and the other end is in a free suspended state / fixed to the hole wall of the airflow channel. There is an included angle α between two adjacent diverting rods (24), and the included angle α is between 30 degrees and 90 degrees. A negative pressure pump (3) is installed at the outlet end of the radon escapement structure (2) to provide a negative pressure environment inside the radon escapement structure (2) and to guide the air flow. The outlet end of the negative pressure pump (3) is connected to a splitter (4). The first passage of the splitter (4) is connected to the atmosphere and is used to discharge the treated air during the radon collection stage of the radon escapement structure (2). The end of the second passage is connected to a radon detection instrument and is used to measure the radon concentration during the radon release stage of the radon escapement structure (2).

2. The apparatus for enrichment and desorption of extremely low radon concentrations according to claim 1, characterized in that, The cross-section of the airflow channel is one of the following: regular hexagon, square, sector, or circle, or any combination of two or three of the above structures.

3. The apparatus for enrichment and desorption of extremely low radon concentrations according to claim 1, characterized in that, The cross-section of the diverter (24) is circular. The diameter of the diverter (24) is 0.25 to 0.28 times the maximum width of the cross-section of the airflow channel. The distance between the center of the diverter (24) and the end face of the second straight cylinder (22) is 1.2 to 2 times the diameter of the diverter (24). The distance between two adjacent diverters (24) is 6 to 8 times the diameter of the diverter (24).

4. The apparatus for enrichment and desorption of extremely low radon concentrations according to claim 3, characterized in that, The diameter of the diverter (24) is 0.26 times the maximum width of the cross-section of the airflow channel. The distance between the center of the diverter (24) and the end face of the second straight cylinder (22) is 1.5 times the diameter of the diverter (24). The distance between two adjacent diverters (24) is 7 times the diameter of the diverter (24).

5. The apparatus for enrichment and desorption of extremely low radon concentrations according to claim 1, characterized in that, The cone angle of the first vertebra (21) is greater than that of the second vertebra (23), and the length of the first vertebra (21) is less than that of the second vertebra (23).

6. The apparatus for enrichment and desorption of extremely low radon concentrations according to claim 1, characterized in that, The inlet end of the radon escapement structure (2) is connected to one end of the first pipeline, and the other end of the first pipeline is vented to introduce air into the first pipeline. A first valve (5) is provided on the first pipeline, and the first valve (5) is used to control the on / off state of the first pipeline.

7. The apparatus for enrichment and desorption of extremely low radon concentrations according to claim 6, characterized in that, The outlet end of the radon escapement structure (2) is connected to one end of the second valve (6), the other end of the second valve (6) is connected to the first port of the four-way valve (7), the second port of the four-way valve (7) is connected to a pressure gauge (8), the third port of the four-way valve (7) is connected to one end of the second pipeline, the fourth port of the four-way valve (7) is connected to one end of the third valve (9), the other end of the third valve (9) is vented for auxiliary exhaust, the negative pressure pump (3) is installed on the second pipeline, the fourth valve (10) is installed between the negative pressure pump (3) and the four-way valve (7), the fourth valve (10) is used to control the on / off state of the second pipeline, and the diverter (4) is connected to the other end of the second pipeline.

8. The apparatus for enrichment and desorption of extremely low radon concentrations according to claim 7, characterized in that, A fifth valve (11) is provided on the first passage of the diverter (4), and the fifth valve (11) is used to control the on / off state of the first passage of the diverter (4). A sixth valve (12) is provided on the second passage of the diverter (4), and the sixth valve (12) is used to control the on / off state of the second passage of the diverter (4). The outlet end of the second passage is detachably connected to the radon detection instrument.

9. The apparatus for enrichment and desorption of extremely low radon concentrations according to claim 8, characterized in that, A measuring component is installed on the first pipeline, which is used to measure the amount of air flowing through the first pipeline.

10. A method for measuring radon concentration in extremely low radon concentration environments, based on the apparatus for enrichment and analysis of extremely low radon concentrations as described in claim 9, characterized in that, Includes the following steps: Open the first valve (5), the second valve (6), the fourth valve (10) and the fifth valve (11), close the third valve (9) and the sixth valve (12), start the negative pressure pump (3), introduce air into the device, and use the radon escapement structure (2) to capture radon in the air; When the measuring component detects that the amount of air flowing through the first pipeline has reached the target volume of air, it closes the first valve (5) and at the same time closes the fifth valve (11) and the negative pressure pump (3) after a preset time, thus ending the radon enrichment process. Start the heating device and pressurizing device to pressurize and heat the inside of the cylinder (1). When the preset value is reached, maintain it for a preset time. Connect the radon detection instrument to the outlet of the sixth valve (12), open the sixth valve (12) and start the negative pressure pump (3) at the same time, and use the radon detection instrument to measure the radon concentration.

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