Device and method for enrichment and analysis of extremely low radon concentration

Abstract

The invention belongs to the technical field of radon concentration measurement, and particularly discloses a device and a method for enrichment and analysis of extremely low radon concentration, the device comprises a vertically placed cylinder, and the cylinder is provided with a heating device and a supercharging device; the radon escapement structure is sleeved with the barrel and is formed by pressing activated carbon fibers, the negative pressure pump is arranged at the outlet end of the radon escapement structure and provides a negative pressure environment for the interior of the radon escapement structure to achieve air drainage and guiding, the outlet end of the negative pressure pump is connected with the flow divider, and a first channel of the flow divider is communicated with the atmosphere. The tail end of the second passage is connected with a radon detection instrument, and the second passage is used for measuring the radon concentration in the radon release stage of the radon escapement structure. According to the invention, the detection lower limit of radon concentration measurement is reduced, the problem that radon concentration in some environments is lower than the detection lower limit of radon measurement equipment and cannot be measured is solved, and support is provided for effectively evaluating the influence of environmental radiation background on extremely low background physical experiments.

Description

Technical Field

[0001] The invention belongs to the technical field of radon concentration measurement, and relates to a device and method for enrichment and analysis of extremely low radon concentration. Background Art

[0002] Radon is a monatomic inert gas that is colorless and odorless. It is soluble in water, blood, fat and a variety of liquids. It is chemically inactive and exists as a free atom in the air. It can decay into a series of new nuclides, namely radon daughters. Radon and its daughters are both solid and radioactive elements. They may affect the accuracy of experimental results during experiments. Therefore, stricter control standards are required for radon in the laboratory.

[0003] Deep underground or in areas far from radioactive deposits, the soil and rocks contain fewer radioactive elements and release less radon, which is very beneficial for certain specific experiments. For example, the Jinping Underground Laboratory in China is located in the Jinping Mountain Tunnel on the Yalong River in Liangshan Prefecture, Sichuan Province. The vertical rock cover is as thick as 2,400 meters, which greatly reduces the impact of cosmic rays. In addition, the underground laboratory uses "waterproof and radon suppression" technology, using a 10-layer complex structure as a "protective shield" for the laboratory. The multi-layer structure shields water and radon gas in the rock, effectively inhibiting the entry of radon gas and providing a low-radon environment for certain experiments.

[0004] Usually, before conducting an experiment, the environmental level needs to be evaluated again. However, for extremely low radon concentration environments, since the radon concentration is lower than the detection limit of the radon measuring equipment, it is impossible to accurately measure it. It is difficult to accurately evaluate the impact of the environmental radiation background on extremely low background physical experiments, making it difficult to ensure the accuracy of the experiment. Summary of the invention

[0005] The purpose of the present invention is to provide a device and method for enrichment and analysis of extremely low radon concentrations, which can allow a large amount of air to quickly flow through a radon escapement structure, so that the radon in the air is captured by the radon escapement structure. After the collected radon is greater than the minimum limit of the detection device, the radon escapement structure is used again to release the captured radon, so that the radon parameters in the current air environment are determined after detection by the instrument, thereby solving the technical problem that the instrument cannot measure the radon concentration in some environments due to the low radon concentration, and effectively reducing the detection lower limit of radon concentration measurement.

[0006] To achieve the above purpose, the present invention provides a device and method for enrichment and analysis of extremely low radon concentrations, and the specific technical scheme is as follows:

[0007] A device for enrichment and analysis of extremely low radon concentrations, comprising:

[0008] The cylinder is placed vertically, and is provided with a heating device and a pressurizing device for adjusting the temperature and air pressure inside the cylinder respectively;

[0009] A radon escapement structure is set 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 on the upper side of 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 in sequence from bottom to top and connected end to end. The second straight cylinder is provided with a plurality of airflow channels, each of which is provided with a plurality of diverter rods spaced along the length direction of the airflow channel, one end of the diverter rod is fixed to the hole wall of the airflow channel, and the other end is in a free hanging state / fixed to the hole wall of the airflow channel, and an angle ɑ is formed between two adjacent diverter rods, and the angle ɑ is between 30 degrees and 90 degrees;

[0010] A negative pressure pump is arranged on the outlet end of the radon escapement structure, and is used to provide a negative pressure environment inside the radon escapement structure to achieve air drainage and guidance. The outlet end of the negative pressure pump is connected to a diverter that can achieve one-to-two divisions. The first passage of the diverter is connected to the atmosphere, and is used to discharge the treated air when the radon escapement structure collects radon. The end of the second passage is connected to a radon detection instrument, and is used to measure the radon concentration when the radon escapement structure releases radon.

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

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

[0013] Preferably, the diameter of the diverter rod is 0.26 times the maximum width of the cross section of the airflow channel, and the distance between the center position of the diverter rod and the end surface of the second straight cylinder is 1.5 times the diameter of the diverter rod.

[0014] Preferably, the taper angle of the first vertebral body is greater than the taper angle of the second vertebral body, and the length of the first vertebral body is less than the length of the second vertebral body.

[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 introduce air 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, the second port of the four-way is connected to a pressure gauge, the third port of the four-way is connected to one end of the second pipeline, the fourth port of the four-way 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 arranged on the second pipeline, a fourth valve is arranged between the negative pressure pump and the four-way, 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, and the fifth valve is used to control the on-off state of the first passage of the diverter. A sixth valve is provided on the second passage of the diverter, and the sixth valve is used 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, and the measuring component is used to measure the amount of air flowing through the first pipeline.

[0019] A method for measuring radon concentration in an extremely low radon concentration environment, based on the above-mentioned device for enrichment and analysis of extremely low radon concentration, comprises the following steps:

[0020] Open the first valve, the second valve, the fourth valve and the fifth valve, close the third valve and the sixth valve, 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, the first valve is closed, and the fifth valve and the negative pressure pump are closed after a delay of a preset time, and the radon enrichment process ends;

[0022] Start the heating device and the pressurizing device to increase the pressure and temperature inside the cylinder. When the preset value is reached, keep it for the preset time.

[0023] Connect the radon detection instrument to the outlet end of the sixth valve, open the sixth valve and start the negative pressure pump at the same time, and use the radon detection instrument to measure the radon concentration.

[0024] Compared with the prior art, the present invention provides a device and method for enriching and analyzing extremely low radon concentrations. The device can allow a large amount of air to quickly flow through a radon escapement structure, so that radon in the air is captured by the radon escapement structure. After the radon collected on the radon escapement structure is greater than the minimum limit of the detection device, the radon escapement structure is used again to release the captured radon, so that the radon parameters in the current air environment are determined after detection by the instrument, thereby solving the technical problem that the radon concentration in some environments is too low to be measured by the instrument, effectively reducing the detection limit of radon concentration measurement, solving the problem that the radon concentration in some environments is lower than the detection limit of the radon measuring equipment and cannot be measured, providing support for effectively evaluating the impact of environmental radiation background on extremely low background physical experiments, providing a theoretical basis and technical means for in-depth research on radon measurement principles and methods, and for research on new methods and new technologies in the fields of radon monitoring and protection, and tracer applications, etc., having great scientific significance and practical value, strong practicality, and worthy of promotion. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0026] Figure 2 It is a schematic diagram of the local structure of the present invention Figure 1 .

[0027] Figure 3 It is a schematic diagram of the local structure of the present invention Figure 2 .

[0028] Figure 4 It is a schematic diagram of the local structure of the present invention Figure 3 .

[0029] Figure 5 It is a schematic diagram of the local structure of the present invention Figure 4 . DETAILED DESCRIPTION

[0030] Radon and its progeny are both solid and radioactive elements, which may affect the accuracy of the experimental results during the test, so stricter control standards are required for radon in the laboratory. Usually, before conducting the test, the environmental level needs to be evaluated again, but for extremely low radon concentration environments, since the radon concentration is lower than the detection limit of the radon measuring equipment, it is impossible to accurately measure it. It is difficult to accurately evaluate the impact of the environmental radiation background on the extremely low background physical experiment, making it difficult to ensure the accuracy of the test.

[0031] In view of the technical problem that the radon concentration in some environments is currently low and cannot be measured by instruments, the present invention provides a new device and method for enrichment and analysis of extremely low radon concentrations.

[0032] In order to enable those skilled in the art to better understand the technical solution of the present invention and to implement it, the following will be combined with the attached Figure 1To the attached Figure 5 , clearly and thoroughly describe the technical solution in the present invention.

[0033] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] In addition, it should be further explained that, in the description of the embodiments of the present invention, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B: “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present invention, “multiple” refers to two or more than two.

[0035] The following terms "first", "second", "third" and "fourth" are used for descriptive purposes only and should not be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", "third" and "fourth" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0036] Example 1

[0037] like Figures 1 to 5 As shown, the present invention provides a device for enrichment and analysis of extremely low radon concentrations, which is used for enrichment and analysis of extremely low radon concentrations. The device structure includes a cylinder 1, which is placed vertically. The reason why the cylinder 1 is designed to be placed vertically here is that the specific gravity of radon and its daughters is greater than that of air, but they have obvious upward migration ability. Basically, the contribution of radon and its daughters to upward migration is >45%, and the contribution to downward migration is <45%. Moreover, the longitudinal migration ability of radon and its daughters is much greater than the lateral migration ability, the former is >90%, and the latter is <10%. When the specific gravity of radon and its daughters is less than that of air, they can rise by themselves. Therefore, radon and its daughters have a "floating" ability that is much greater than diffusion and gravity sedimentation. Therefore, the vertical design of the cylinder 1 is conducive to the rapid separation of radon in the air. At the same time, the vertical setting conforms to the migration law of radon, which is conducive to improving the enrichment efficiency of radon.

[0038] A radon escapement structure 2 is arranged in a sleeve manner in the barrel 1. The radon escapement structure 2 has an inlet end and an outlet end, wherein the outlet end is at the upper end and the inlet end is at the lower end.

[0039] A first pipeline is arranged at the lower end of the cylinder 1, and a first end of the first pipeline is connected to the inlet end of the radon escapement structure 2, and a second end of the first pipeline is vented, that is, connected to air, for introducing air into the first pipeline. In addition, in order to facilitate the control of the on-off state of the first pipeline, a first valve 5 is arranged at the second end of the first pipeline. When the first valve 5 is opened, air enters the radon escapement structure 2 in the cylinder 1 through the first pipeline, and radon in the air is captured by the radon escapement structure 2, and other processed 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, and the second pipeline is also connected to a negative pressure pump 3. The negative pressure pump 3 is used to provide a negative pressure environment inside the entire device, thereby prompting the air to enter the device through the first pipeline and be discharged through the second pipeline. The outlet end of the second pipeline is connected to a one-to-two splitter 4, and the splitter 4 divides the pipeline into two paths. The first path is connected to the atmosphere as an exhaust port, which is used to discharge the treated air through it. The exhaust port is provided with a fifth valve 11 for controlling the on-off state of the exhaust port. The second path is provided with a sixth valve 12, and the outlet end of the sixth valve 12 is used to be connected to a radon detection instrument.

[0041] Furthermore, in order to facilitate the control of the passage state and the measurement, a four-way valve 7 is provided at the inlet end of the second pipeline, wherein 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 vented for auxiliary exhaust.

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

[0043] As a further refinement of the 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 vertebral body 21, a second straight cylinder 22 and a second vertebral body 23 which are arranged in sequence from bottom to top and connected end to end, wherein the cone angle of the first vertebral body 21 is greater than the cone angle of the second vertebral body 23, and the length of the first vertebral body 21 is less than the length of the second vertebral body 23. The cone angle of the first vertebral body 21 is large and short, which is convenient for quickly expanding and reducing the pressure of the air and then introducing it into the second straight cylinder 22, while the cone angle of the second vertebral body 23 is small and long, which is convenient for forming a Laval effect, so that the treated air can be pressurized and accelerated before being exported.

[0044] In order to facilitate the connection, a first straight cylinder is connected to the first vertebra 21 and is used to communicate with one end of the first pipeline. A third straight cylinder is connected to the second vertebra 23 and is used to communicate with one end of the second pipeline.

[0045] Among them, activated carbon fiber is a new type of functional fiber made through different routes with organic fiber as precursor. As the third generation of new functional adsorption 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 structure and attach a porous structure to effectively enhance its enrichment effect on radon.

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

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

[0048] Furthermore, as a further optimization solution of the embodiment of the present invention, when the cross section of the airflow channel is circular, the force is best and the manufacturability is best.

[0049] Furthermore, as a further refinement of the embodiment of the present invention, in order to further increase the contact area between the air and the radon escapement structure 2 and thus increase the adsorption capacity of radon, a plurality of diverter rods 24 are provided in each air flow channel, such as Figure 3 As shown, a plurality of diverter rods 24 are arranged at intervals along the length direction of the air flow channel. The diverter rods 24 are located on one side of the second straight tube 22 close to the first vertebral body 21. One end of the diverter rod 24 is fixed to the hole wall of the air flow channel, and the other end is freely suspended.

[0050] Further, as a further refinement of the embodiment of the present invention, Figures 3 to 5 As shown, there is an angle ɑ between two adjacent diverter rods 24, and the angle ɑ is between 30 degrees and 90 degrees. This can cause the direction of the Karman vortex street formed by the bypass effect after the air passes through different diverter rods 24 to be misaligned, so that it will not accumulate at a fixed position on the wall and be saturated prematurely. Under the effect of the misalignment, the adsorption of the wall can be made more uniform, thereby improving its radon enrichment capacity.

[0051] Further, as another optimization solution of the embodiment of the present invention, Figure 4As shown, both ends of the diverter rod 24 can be fixed to the hole wall of the air flow channel.

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

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

[0054] During use, air containing radon enters the second straight cylinder 22 through the small end of the first vertebral body 21, forming a pressure reduction and expansion effect, which reduces the pressure of the air and slows down the speed. This is beneficial to increase the adsorption effect of the second straight cylinder 22 when entering the second straight cylinder 22. At the same time, when the air enters the airflow channel on the second straight cylinder 22, under the action of the diverter rod 24, a bypass effect will be generated in the airflow channel on the rear side of the diverter rod 24, thereby forming a Karman vortex street under multi-stage action in the airflow channel. Under the action of the Karman vortex street, the radon in the air collides with the wall of the airflow channel and is captured on the wall. As the number of times the air flow collides with the wall of the airflow channel increases, the radon The contact probability with the wall surface increases, so that more radon is captured by the wall surface, thereby improving the radon capture efficiency of the radon escapement structure 2. When the air flows from the second straight cylinder 22 through the second vertebral body 23, the diameter of the second vertebral body 23 becomes smaller and smaller along the flow direction of the air, thus forming a Laval tube structure. The air produces a Laval nozzle effect in this section, thereby increasing the number of collisions between particles in the air. Due to the violent movement, the probability of collision with the wall surface of the second vertebral body 23 increases, so the radon capture efficiency of the second vertebral body 23 increases. In addition, due to the Laval effect, the flow rate of the air in this section is increased, 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 processed air flows out from 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 may be further provided on the first pipeline, wherein the measuring component is used 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, the third valve 9 and the sixth valve 12 are closed, the first valve 5, the second valve 6, the fourth valve 10 and the fifth valve 11 are opened, the negative pressure pump 3 is started, air is introduced into the device, and the radon escapement structure 2 is used to capture radon in the air. When the measuring component confirms that the target volume of air has passed, a control command is issued to the first valve 5 to close, and a control command is issued to the fifth valve 11 and the negative pressure pump 3 to close after a delay of 5 seconds. The purpose of the delay is to continue to discharge the air, and the enrichment process ends.

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

[0060] Furthermore, as a further refinement of an 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 for controlling 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 and 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 mounted on the cylinder 1, and the heating coil is electrically connected to the electric control box. The temperature of the heating coil can be adjusted in real time through the electric control box, so that the temperature of the radon escapement structure 2 built into the cylinder 1 changes. The higher the temperature of the radon escapement structure 2, the lower the adsorption coefficient of the radon escapement structure 2, and thus the higher the radon precipitation rate. The heating is continued for 5 to 10 minutes. 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. The radon adsorbed by the radon escapement structure 2 can be fully resolved. The air inside the device body is extracted from the outlet end of the sixth valve 12 by the negative pressure pump 3 and input into the radon detection instrument for measurement.

[0062] Example 2

[0063] As a further improvement scheme based on the technical foundation of the embodiment, in order to increase the precipitation rate of radon, a booster device is set on the cylinder 1, and the booster device is used to increase the air pressure inside the cylinder 1 to between 3 atmospheres and 4 atmospheres. When the air pressure inside the cylinder 1 increases, the precipitation rate of radon is fast. The pressure and temperature can be increased at the same time to facilitate the rapid precipitation of radon and improve the efficiency of the measurement.

[0064] Furthermore, the pressure gauge 8 provided on the device plays a safety protection role and is used to measure the pressure at the outlet of the radon escapement structure 2 to prevent the pressure from exceeding a preset value during the pressurization process of the booster device, thereby causing safety hazards.

[0065] A method for measuring radon concentration in an extremely low radon concentration environment, based on the above-mentioned device for enrichment and analysis of extremely low radon concentration, comprises the following steps:

[0066] The first valve 5, the second valve 6, the fourth valve 10 and the fifth valve 11 are opened, the third valve 9 and the sixth valve 12 are closed, the negative pressure pump 3 is started, air is introduced into the device, and the radon escapement structure 2 is used to capture radon in the air.

[0067] When the measuring component detects that the amount of air flowing through the first pipeline has reached the target volume of air, the first valve 5 is closed, and the fifth valve 11 and the negative pressure pump 3 are closed after a delay of 5 seconds, and the radon enrichment process ends.

[0068] At this time, the heating device and the pressurizing device can be started to increase the pressure and temperature of the cylinder 1. When the internal temperature of the cylinder 1 is between 400°C and 450°C, and the internal pressure of the cylinder 1 is between 3 atmospheres and 4 atmospheres, maintain it for 5 to 10 minutes, connect the radon detection instrument to the outlet end 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 may be provided outside the cylinder 1 to prevent the cylinder 1 from scalding the operator.

[0070] Specifically, the protective structure may be a cylindrical structure made of a heat-insulating material, and the cylindrical structure may be sleeved on the cylinder body 1 .

[0071] As a further improvement scheme based on the technical foundation of the embodiment, the thermal insulation material may be one of glass fiber, asbestos, rock wool, silicate, aerogel felt or vacuum panel.

[0072] The device and method for enrichment and analysis of extremely low radon concentrations provided by the present invention can be used to measure radon concentrations in extremely low radon concentration environments, solve the problem that the radon concentration in certain environments is lower than the detection limit of radon measuring equipment, resulting in the inability to measure, provide support for effectively evaluating the impact of environmental radiation background on extremely low background physical experiments, provide a theoretical basis and technical means for in-depth research on radon measurement principles and methods, and for research on new methods and new technologies in the fields of radon monitoring and protection, tracing applications, etc., and have great scientific significance and practical value.

[0073] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present invention are within the scope of protection of the present invention.

Claims

1. A device for enrichment and analysis of extremely low radon concentrations, characterized in that: include: The cylinder (1) is placed vertically, and a heating device and a pressurizing device are provided on the cylinder (1) for adjusting the temperature and air pressure inside the cylinder (1) respectively; A radon escapement structure (2) is set 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 comprises a first cone (21), a second straight cylinder (22) and a second cone (23) arranged in sequence from bottom to top and connected end to end, the second straight cylinder (22) is provided with a plurality of air flow channels, each air flow channel is provided with a plurality of diverter rods (24) arranged at intervals along the length direction of the air flow channel, one end of the diverter rod (24) is fixed to the hole wall of the air flow channel, and the other end is in a free hanging state / fixed to the hole wall of the air flow channel, and an angle ɑ is formed between two adjacent diverter rods (24), and the angle ɑ is between 30 degrees and 90 degrees; A negative pressure pump (3) is arranged at the outlet end of the radon escapement structure (2) and is used to provide a negative pressure environment inside the radon escapement structure (2) to achieve air drainage and guidance. The outlet end of the negative pressure pump (3) is connected to a diverter (4). The first passage of the diverter (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 device for enrichment and analysis of extremely low radon concentration according to claim 1, characterized in that: The cross section of the airflow channel is one of a regular hexagon, a square, a sector, and a circle, or a combination of any two or three of the above structures.

3. The device for enrichment and analysis of extremely low radon concentration according to claim 1, characterized in that: The cross-section of the diverter rod (24) is circular, the diameter of the diverter rod (24) is 0.25 to 0.28 times the maximum width of the cross-section of the airflow channel, the distance between the center position of the diverter rod (24) and the end surface of the second straight cylinder (22) is 1.2 to 2 times the diameter of the diverter rod (24), and the distance between two adjacent diverter rods (24) is 6 to 8 times the diameter of the diverter rod (24).

4. The device for enrichment and analysis of extremely low radon concentration according to claim 3, characterized in that: The diameter of the diverter rod (24) is 0.26 times the maximum width of the cross section of the air flow channel, the distance between the center position of the diverter rod (24) and the end surface of the second straight cylinder (22) is 1.5 times the diameter of the diverter rod (24), and the distance between two adjacent diverter rods (24) is 7 times the diameter of the diverter rod (24).

5. The device for enrichment and analysis of extremely low radon concentration according to claim 1, characterized in that: The cone angle of the first vertebral body (21) is greater than the cone angle of the second vertebral body (23), and the length of the first vertebral body (21) is less than the length of the second vertebral body (23).

6. The device for enrichment and analysis of extremely low radon concentration 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 device for enrichment and analysis of extremely low radon concentration according to claim 6, characterized in that: The outlet end of the radon escapement structure (2) is connected to one end of a second valve (6), the other end of the second valve (6) is connected to a first port of a 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 a second pipeline, the fourth port of the four-way valve (7) is connected to one end of a third valve (9), the other end of the third valve (9) is vented for auxiliary exhaust, a negative pressure pump (3) is arranged on the second pipeline, a fourth valve (10) is arranged 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 device for enrichment and analysis of extremely low radon concentration 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 device for enrichment and analysis of extremely low radon concentration according to claim 8, characterized in that: The first pipeline is provided with a measuring component, and the measuring component is used to measure the amount of air flowing through the first pipeline.

10. A method for measuring radon concentration in an environment with extremely low radon concentration, based on the device for enrichment and analysis of extremely low radon concentration as claimed in claim 9, characterized in that: The following steps are involved: Opening the first valve (5), the second valve (6), the fourth valve (10) and the fifth valve (11), closing the third valve (9) and the sixth valve (12), starting the negative pressure pump (3), introducing air into the device, and using 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, the first valve (5) is closed, and at the same time, the fifth valve (11) and the negative pressure pump (3) are closed after a delay of a preset time, and the radon enrichment process ends; The heating device and the pressurizing device are started to increase the pressure and temperature inside the cylinder (1), and when the pressure reaches a preset value, the pressure is maintained for a preset time; A radon detection instrument is connected to the outlet end of the sixth valve (12), the negative pressure pump (3) is started while the sixth valve (12) is opened, and the radon concentration is measured using the radon detection instrument.

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