Measuring chamber for calibrating radon Rn222 of emanometer and testing method of measuring chamber

Abstract

The invention relates to the field of radon Rn222 measurement, in particular to a calibration radon Rn222 measurement chamber of a radon detector and a test method of the calibration radon Rn222 measurement chamber. A radon measuring chamber for calibrating and calibrating radon Rn222 of a radon measuring instrument comprises a sealing chamber; the laser chloride 226 decay chamber is arranged in the sealed measurement chamber and is provided with a decay chamber, so that the laser chloride 226 radiates and decays to release radon Rn222, and an air inlet hole and an air outlet hole are formed in the two ends of the laser chloride 226 decay chamber respectively; the radon measuring instrument assembly is arranged at one end of the decay chamber of the radium chloride 226 and is communicated with the air outlet hole, and the radon measuring instrument assembly is provided with a plurality of radon measuring instruments so as to measure radon Rn222 released by radium chloride 226 radiation decay; and an air inlet assembly. Functional integration is achieved through modular design, and the problems that a traditional calibration device is scattered in structure and complex in operation are solved. The parallel measurement design of multiple radon meters breaks through the single-channel efficiency bottleneck and meets the batch calibration requirement; the linkage of the gas inlet assembly and the decay chamber ensures that the radon gas concentration is stable, and a foundation is laid for high-precision calibration.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radon Rn222 measurement, in particular to a radon Rn222 measurement room for calibrating a radon detector and a test method thereof. BACKGROUND

[0002] Radon is a gaseous radioactive element, and there are three isotopes of radon in nature: 222Rn, 220Rn and 219Rn. Due to the large difference in half-life, the measurement and protection of radon at present are mainly aimed at 222Rn, and the half-life is 3.825d.

[0003] At present, the calibration of the radon detector mainly depends on the standard radon chamber or radon source device of the professional laboratory. Among them, the standard radon chamber generates a stable concentration of radon gas environment in a closed space to realize the precision verification of the radon detector, and the core principle is to use radium-226 (226Ra) and other radioactive nuclides to produce radon gas, and to maintain the stability of the radon concentration through temperature, humidity and air pressure control modules. In addition, some schemes use small radon sources to generate radon gas with a gas system, but such devices can usually only support the calibration of a single instrument, and the dynamic range of radon concentration is limited.

[0004] For the above prior art, the inventor found that the existing standard radon chamber relies on precise control equipment and large-area shielding facilities, and the construction cost of a single set is high. The traditional radon chamber adopts an overall space filling mode, and needs to maintain a high-concentration radon gas environment of several cubic meters. The radon gas consumption is large and difficult to recover, which not only increases the cost of radioactive waste treatment, but also has the risk of environmental pollution caused by leakage. The small radon source device is mostly designed as a single channel, and only 1-2 radon detectors can be calibrated at a time, which cannot match the high-efficiency calibration demand in large-scale production. Moreover, some schemes use short half-life radon sources, which need to frequently replace the radon source consumables or rely on a complex gas circulation system to maintain the concentration stability, thereby increasing the long-term operation and maintenance cost. SUMMARY

[0005] Based on the technical problems existing in the prior art, the present application provides a radon Rn222 measurement room for calibrating a radon detector and a test method thereof.

[0006] In a first aspect, the present application provides a radon Rn222 measurement room for calibrating a radon detector, which adopts the following technical scheme: A radon Rn222 measurement room for calibrating a radon detector comprises: A sealed chamber is provided with a sealed measurement cavity, and one-way valve groups are arranged on both sides of the sealed chamber to adjust the air pressure inside the sealed measurement cavity. A radium-226 chloride decay chamber is arranged in the sealed measurement chamber and is provided with a decay chamber to release radon Rn222 by radioactive decay of radium-226 chloride, and the radium-226 chloride decay chamber is respectively provided with an air inlet hole and an air outlet hole at two ends thereof; A radon measurement instrument assembly is arranged at one end of the radium-226 chloride decay chamber and is in communication with the air outlet hole, and the radon measurement instrument assembly is provided with a plurality of radon measurement instruments to measure radon Rn222 released by radioactive decay of radium-226 chloride. An air inlet assembly is arranged at the other end of the radium-226 chloride decay chamber and is in communication with the air inlet hole, and the air inlet assembly is provided with an air inlet fan to introduce air into the radium-226 chloride decay chamber.

[0007] Through the above technical solution, the radon calibration system is constructed by integrating the sealed chamber, the radium-226 chloride decay chamber, the radon measurement instrument assembly and the air inlet assembly. The sealed chamber adjusts the air pressure by the one-way valve group to form a closed measurement environment. The radium-226 chloride decay chamber generates radon gas by using the principle of radioactive decay. The air inlet assembly introduces dry air to drive the flow of radon gas. The radon measurement instrument assembly realizes parallel measurement through multi-channel design. The modules work together to form a closed-loop system of radon gas generation, transmission, measurement and environment control. The modular design realizes functional integration, solving the problems of dispersed structure and complex operation of traditional calibration equipment. The cooperation of the sealed chamber and the one-way valve group ensures that radon gas does not leak, improving safety. The parallel measurement design of multiple radon measurement instruments breaks through the single-channel efficiency bottleneck and meets the batch calibration demand. The linkage of the air inlet assembly and the decay chamber ensures the stability of radon gas concentration, laying a foundation for high-precision calibration.

[0008] Further, the one-way valve group includes a one-way air inlet valve and a one-way air outlet valve, which are respectively arranged on the outer peripheral surface of the sealed chamber and are in communication with the sealed measurement chamber to seal the sealed measurement chamber when the pressure in the sealed measurement chamber is close to the external pressure. The one-way air inlet valve and the one-way air outlet valve adopt a gravity type self-closing structure, and the valve plate of the one-way air inlet valve and the one-way air outlet valve is made of radiation-resistant organic glass material.

[0009] Through the above technical solution, the control system of the traditional electric valve is simplified by the gravity type self-closing structure, reducing the failure rate and energy consumption. The radiation-resistant material prolongs the service life of the valve and avoids the material aging problem in the long-term radiation environment. The independent arrangement of the two-way valve ensures that the sealed chamber can be closed during the calibration stage and can be efficiently ventilated during the exhaust stage, balancing safety and operational convenience.

[0010] Further, the radium-226 chloride decay chamber includes: A housing formed of stainless steel metal and provided with a containing chamber; a shielding inner layer, which is arranged in the accommodating cavity and connected to the inner wall surface of the shell in abutment, and is provided with a decay chamber; a plurality of filter screen packages, each of which is arranged in the decay chamber and formed as a melt-blown cloth filter screen piece, and each of which is wrapped with radium chloride 226.

[0011] Through the above technical solution, the structure of the radium chloride 226 decay chamber is further refined, mechanical support is provided by the stainless steel shell, the shielding inner layer blocks radiation, and the melt-blown cloth filter screen package encapsulates the radioactive source. The porous structure of the melt-blown cloth allows radon gas to pass through while retaining radioactive dust; the plurality of filter screen packages are arranged dispersedly to improve the radon gas emanation efficiency. The combination of the shell and the shielding inner layer forms double protection to prevent radiation leakage. The melt-blown cloth filter screen package design solves the problem of low radon gas emanation rate in traditional radioactive source encapsulation, improves the calibration efficiency; the synergistic effect of the shielding inner layer and the shell ensures that the radiation protection meets the standard and reduces the health risk of the operator; the modular filter screen package is convenient to replace and maintain, and avoids the cost waste caused by the overall replacement of the radioactive source.

[0012] Further, the shielding inner layer material includes a metal lead sheet with a thickness of not less than 5 mm.

[0013] Through the above technical solution, the shielding inner layer uses a metal lead sheet with a specific thickness, which utilizes the high-density characteristics of lead to attenuate ionizing radiation. The lead sheet is tightly attached to the stainless steel shell to form a continuous shielding layer, covering the entire decay chamber to ensure that the radiation leakage path is blocked from the source. Passive protection is achieved through the physical properties of the material itself, without relying on electronic equipment, which is more reliable. The lead sheet with sufficient thickness ensures that the radiation dose meets the safety standard, provides a basic guarantee for the long-term stable operation of the equipment, and simplifies the system design complexity of radiation protection.

[0014] Further, the radon measurement instrument assembly includes: a total gas outlet pipe, one end of which is connected in communication with one end of the decay chamber, and the total gas outlet pipe is provided with a dust filter screen to filter the gas discharged from the decay chamber; a plurality of branch gas outlet pipes, each of which is arranged at the other end of the total gas outlet pipe and formed as a pipe-shaped piece, and the outer peripheral surface of each of the branch gas outlet pipes is provided with a plurality of radon outlet holes penetrating along the thickness direction of the pipe wall; a plurality of radon measurement instruments, each of which is arranged on the branch gas outlet pipe in one-to-one correspondence with each of the radon outlet holes to calibrate the radon Rn222 contained in the gas.

[0015] Through the above technical solution, the present application constructs a multi-channel gas distribution system through the hierarchical structure of the total gas outlet pipe, branch gas outlet pipe and radon measuring instrument. The total gas outlet pipe collects radon gas generated by the decay chamber, purifies it through the dust filter screen, and then uniformly distributes it to each radon measuring instrument through the fine holes of the branch gas outlet pipe. The fine holes control the flow of radon gas to ensure that the concentration of each channel is consistent; multiple radon measuring instruments correspond to fine holes one by one to realize parallel calibration. The multi-branch design breaks through the efficiency limit of traditional single-channel calibration, significantly improving batch processing capacity; the dust filter screen reduces the interference of radioactive dust on the radon measuring instrument, ensuring measurement accuracy; the fine hole distribution structure ensures the consistency of radon gas parameters in each channel, avoids calibration errors caused by flow differences, and improves the reliability of multi-instrument comparative analysis.

[0016] Further, the air inlet assembly comprises: a fan, one end of which is in communication with external air and is provided with an air inlet filter screen; an air inlet pipeline, one end of which is in communication with the other end of the fan, and the other end of the air inlet pipeline is in communication with the air inlet hole of the radium chloride 226 decay chamber; a drying part, which is provided on the air inlet pipeline and has a granular drying agent inside to dry the gas sent into the air inlet pipeline by the fan.

[0017] Through the above technical solution, the present application constructs an air pretreatment system through the combination of the fan, air inlet pipeline and drying part. After being filtered by the air inlet filter screen, the external air is sent into the drying part by the fan, and the water vapor is adsorbed by the granular drying agent. The dried air enters the decay chamber to drive the flow of radon gas. The setting of the drying part cuts off the interference path of water vapor on the stability of radon gas concentration. The air inlet filter screen and the drying part work together to prevent dust and water vapor from entering the decay chamber, prevent filter screen blockage and radon gas concentration fluctuation, and prolong the equipment maintenance cycle; the fan provides stable airflow power to ensure uniform distribution of radon gas in the air path and improve the controllability of the calibration environment; the pretreated air reduces the interference of the radon measuring instrument sensor, indirectly improving the accuracy of the measurement data.

[0018] Further, a main air inlet valve is arranged between the fan and the radium chloride 226 decay chamber, a main air outlet valve is arranged between the radium chloride 226 decay chamber and the radon measuring instrument assembly, and the fan is in communication with the main air inlet valve and the main air outlet valve.

[0019] Through the above technical solution, the present application introduces a fan to control the gas exchange of the sealed chamber through linkage with the main air inlet valve and the main air outlet valve. The active ventilation mode is more thorough than natural diffusion, reducing the interference of residual radon gas on subsequent operations.

[0020] In a second aspect, the present application provides a method for calibrating a radon Rn222 measuring chamber using a radon measuring instrument, which adopts the following technical solution: A method for calibrating a radon Rn222 measurement chamber by using a radon detector, comprising the following steps: Close the sealed chamber and adjust the one-way valve group to the closed state, start the fan of the air inlet assembly, and make the radium chloride 226 in the radium chloride 226 decay chamber release radon Rn222 by radioactive decay, and after the radon concentration is stable, place the radon detector in the sealed chamber for calibration; After the test is completed, the sealed chamber fan is started, and the radon-containing gas in the sealed measurement chamber is discharged through the sealed chamber air inlet valve and the sealed chamber air outlet valve.

[0021] Through the above technical solution, the determination method is optimized into four stages of calibration preparation, concentration stabilization, measurement execution and exhaust ending. By closing the sealed chamber, starting the air inlet assembly to generate a stable radon gas environment, and opening the fan to discharge the residual gas after calibration. The sequence control of each step ensures that the radon concentration reaches a steady state before measurement, and the exhaust stage prioritizes operational safety.

[0022] In summary, the present application has the following beneficial effects: First, the present application realizes significant improvement in calibration efficiency through systematic structural innovation. First, the radon detector assembly adopts a hierarchical design of a total air outlet pipe combined with multiple branch air outlet pipes, which enables radon gas to be evenly distributed to multiple radon detectors through a fine pore structure, breaking through the limitations of traditional single-channel calibration, supporting parallel measurement of multiple devices, and greatly improving the single calibration throughput. Second, the linkage design of the air inlet assembly and the radium chloride 226 decay chamber optimizes the radon gas generation and transmission path, and the dry air drives the stable flow of radon gas, shortening the waiting time for the concentration to reach a steady state. In addition, the standardized operation process clearly defines the stage control logic of sealing-gas production-calibration-exhaust, reduces the uncertainty of human operation, and improves the consistency and repeatability of batch calibration. This synergistic mechanism of hardware parallelization and process standardization effectively solves the problem of low efficiency and difficulty in matching large-scale production needs in existing solutions, providing an efficient calibration solution for radon detector manufacturers.

[0023] Second, the application constructs a multi-level security protection system from structural design to control logic. In terms of radiation shielding, the radium chloride 226 decay chamber adopts a double protection structure of stainless steel shell and lead sheet shielding inner layer, which attenuates ionizing radiation through high-density lead material to reduce the risk of radiation leakage from the source; the packaging design of the melt-blown cloth filter screen package effectively traps radioactive dust, avoiding secondary pollution. In terms of radon gas leakage control, the one-way valve group of the sealed chamber adopts a gravity type self-closing structure, which automatically closes when the pressure is balanced, ensuring the closed nature during the calibration stage; after the test is completed, the sealed chamber fan quickly exhausts the residual radon gas through active ventilation, combined with the directional exhaust design of the one-way exhaust valve, significantly reducing the indoor radon gas concentration. In addition, the linkage logic of the electrical control system automates the processes of air intake, gas production, and exhaust, reducing the contact time of the operator with the radioactive environment. These designs, through passive protection combined with active control, not only meet the requirements of radiation safety specifications, but also reduce the potential pollution to the environment, achieving a double improvement in safety and environmental protection.

[0024] Third, the application significantly reduces the total life cycle cost of the equipment through modular and integrated design. In terms of core components, the radium chloride 226 decay chamber adopts a detachable melt-blown cloth filter screen package structure, which can restore functionality by replacing the filter screen package only when the radioactive source activity decays, without the need for overall replacement of the decay chamber, significantly reducing consumable costs; the granular desiccant of the drying part adopts an independent filling design, which facilitates quick replacement during regular maintenance, avoiding complex system disassembly. In terms of system integration, the compact layout of the sealed chamber, decay chamber, and gas path components reduces space occupation, lowering installation and transportation costs; the gravity type structure of the one-way valve group eliminates the complex control system of traditional electric valves, reducing failure rate and energy consumption. Independent fan control and standardized processes simplify the operation steps, effectively solving the problems of complex maintenance and high long-term operation and maintenance costs in existing solutions, improving the economic efficiency and market applicability of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0025] Fig. 1 FIG. 1 is a structural schematic diagram of a radium chloride 226 decay chamber in an embodiment of the application; Fig. 2 FIG. 2 is a structural schematic diagram of an air intake and exhaust device in an embodiment of the application.

[0026] Wherein, 1, sealed chamber; 11, one-way air inlet valve; 12, one-way air outlet valve; 13, air exhaust device; 131, sealed chamber fan; 132, sealed chamber air inlet valve; 133, sealed chamber air outlet valve; 2, radium chloride 226 decay chamber; 21, shell; 22, shielding inner layer; 23, filter screen package; 24, air inlet hole; 25, air outlet hole; 3, radon meter assembly; 31, total air outlet pipe; 32, branch air outlet pipe; 33, radon air outlet fine hole; 4, air intake assembly; 41, fan; 42, air intake pipeline; 43, drying part. DETAILED DESCRIPTION

[0027] The application will be further described in detail below in combination with the embodiments.

[0028] The application discloses a radon Rn222 measuring chamber for calibrating a radon detector.

[0029] With reference to Figs. 1-2 The radon Rn222 measuring chamber for calibrating the radon detector comprises a sealed chamber 1 which is a closed cavity structure made of glass. The sealed chamber 1 has an independent sealed measuring cavity formed inside. The main frame of the sealed chamber 1 is made of metal, and the outside is covered with shielding material to reduce external environmental interference. A one-way valve group is embedded on the outer walls of the adjacent two sides of the sealed chamber 1. The one-way valve group comprises a one-way air inlet valve 11 and a one-way air outlet valve 12, both of which are directly communicated with the sealed measuring cavity. The one-way air inlet valve 11 is used for the one-way inflow of external air, and the one-way air outlet valve 12 is used for the one-way discharge of internal gas. The sealed chamber 1 is also provided with an exhaust device 13 at the top. The one-way air inlet valve 11 and the one-way air outlet valve 12 are connected with the air inlet and the air outlet of the sealed measuring cavity respectively. The one-way air inlet valve 11 and the one-way air outlet valve 12 are both gravity type self-closing structures. The valve plate is made of radiation-resistant organic glass, and the automatic closure when pressure balance is achieved through the self-weight.

[0030] Inside the sealed chamber 1, a radium226 chloride decay chamber 2 is horizontally arranged. Air inlet holes 24 and air outlet holes 25 are respectively formed in the end faces of the two ends of the radium226 chloride decay chamber 2. The radium226 chloride decay chamber 2 is a cylindrical metal piece as a whole. A shell 21 made of stainless steel metal material is arranged outside the radium226 chloride decay chamber 2. An accommodating cavity is processed inside the shell 21. A shielding inner layer 22 made of metal lead sheet is closely attached to the inner wall of the accommodating cavity, and forms a decay cavity matched with the shape of the shell 21. A plurality of filter screen bags 23 made of melt-blown cloth material are evenly distributed in the decay cavity, and the radium226 chloride powder is wrapped inside.

[0031] On one side of the air outlet hole 25 of the radium226 chloride decay chamber 2, a radon detector assembly 3 is fixedly connected. The radon detector assembly 3 comprises a total air outlet pipe 31 which is a hard pipe. The total air outlet pipe 31 is provided with a dust filter screen at one end, and is branched into a plurality of branch air outlet pipes 32 through a multi-way joint at the other end. The branch air outlet pipe 32 is an elongated pipe type piece. A plurality of radon air outlet fine holes 33 are evenly distributed on the outer circumferential surface of the branch air outlet pipe 32 in the axial direction. The branch air outlet pipe 32 extends radially or in parallel from the end of the total air outlet pipe 31, and is located in the upper or middle region of the sealed measuring cavity. A radon detector probe is connected and arranged in communication with each radon air outlet fine hole 33.

[0032] On one side of the air inlet hole 24 of the radium chloride 226 decay chamber 2, an air inlet assembly 4 is connected, which includes a fan 41, one end of which is connected with a flexible air inlet pipeline 42, and a drying part 43 is installed on the air inlet pipeline 42, the inside of the drying part 43 is filled with granular desiccant, and both ends are provided with air-permeable partitions.

[0033] A method for calibrating a radon Rn222 measuring chamber by using a radon measuring instrument, comprising the following steps: 1. Check the appearance of the sealed chamber 1 to ensure that the glass cavity is not damaged, the metal frame and the shielding material are connected tightly; confirm that the gravity self-closing valve of the one-way air inlet valve 11 and the one-way air outlet valve 12 is in a natural closed state, and the rad-hard organic glass valve has no cracks or deformation; Check the radium chloride 226 decay chamber 2: confirm that the stainless steel shell 21 is tightly attached to the shielding inner layer 22, and the melt-blown cloth filter screen package 23 is evenly distributed in the decay chamber without damage or displacement; the connection flanges of the air inlet hole 24 and the air outlet hole 25 are sealed well; The dust filter screen on the total air outlet pipe 31 is installed in place, the radon outlet fine hole 33 of the branch air outlet pipe 32 is not blocked, and the connection interface between the radon measuring instrument probe and the fine hole is clean and free of foreign matter; Check the air inlet assembly 4: the drying part 43 at the air inlet end of the fan 41 has been filled with granular desiccant, the air inlet filter screen has no dust accumulation, and the flexible air inlet pipeline 42 has no bending or leakage; Open the exhaust device 13 at the top of the sealed chamber 1, confirm that the pipeline connection is normal, and prepare for the subsequent air exchange operation.

[0034] 2. Close the one-way air inlet valve 11 and the one-way air outlet valve 12, start the sealed chamber fan 131, open the sealed chamber air inlet valve 132 and the sealed chamber air outlet valve 133, so that the external fresh air enters the sealed measuring chamber through the air inlet valve and is then discharged through the air outlet valve, and the air exchange is continued for 10-15 minutes to remove the residual gas in the chamber; Close the sealed chamber fan 131 and the corresponding air inlet valve and air outlet valve, stand for 5 minutes, balance the sealed measuring chamber with the external air pressure through the gravity self-closing structure of the one-way valve group, and ensure the initial sealing performance; Connect each radon measuring instrument probe with the radon outlet fine hole 33 of the branch air outlet pipe 32 one by one, turn on the power of the radon measuring instrument, preheat it, and ensure that the equipment is in normal working condition.

[0035] 3. Start the fan 41 of the air inlet assembly 4, and the external air is filtered by the air inlet filter screen, dried by the drying part 43, and then enters the air inlet hole 24 of the radium chloride 226 decay chamber 2 through the flexible air inlet pipeline 42, to drive the air flow in the decay chamber; ensure that the dried air uniformly passes through the melt-blown cloth filter screen package 23, and carries the radon Rn222 gas generated by the decay of radium chloride 226 to the direction of the air outlet hole 25; Radon gas enters the total outlet pipe 31 through the outlet hole 25 of the decay chamber, and after filtering radioactive dust through the dust filter screen, it is divided into multiple branch outlet pipes 32, and finally contacts the radon meter probe through the radon outlet fine hole 33. Keep the air inlet fan 41 running continuously to circulate radon gas in the sealed measurement chamber until the concentration reaches dynamic equilibrium.

[0036] 4. After the radon gas concentration stabilizes, start the measurement program of all radon meters simultaneously, and record the initial reading.

[0037] Record the measurement values of each radon meter at preset time intervals, and continuously collect at least 3 groups of data to ensure that the data repeatability meets the requirements.

[0038] If calibration at different concentration points is required, the radon gas concentration can be changed by adjusting the speed of the air inlet fan 41, and the above stabilization and measurement steps are repeated. Compare the measurement results of each radon meter, calculate the relative deviation, and eliminate abnormal values; if the deviation exceeds the allowed range, check whether the radon outlet fine hole 33 of the corresponding branch outlet pipe 32 is blocked or the radon meter probe connection is loose, and re-measure after troubleshooting.

[0039] 5. Radon gas discharge and sealing chamber 1 purification After calibration is complete, turn off the fan 41 of the air inlet assembly 4, disconnect the radon meter probe from the branch outlet pipe 32, and remove the probe from the sealed measurement chamber. Turn on the sealing chamber fan 131, the sealing chamber inlet valve 132 and the sealing chamber outlet valve 133, and force the radon-containing gas in the sealed measurement chamber to be discharged to the designated radioactive waste gas treatment system through the one-way outlet valve 12. Continue to ventilate for more than 30 minutes until the radon concentration in the chamber is reduced to below the safety limit; Turn off all valves and fans 41, check whether the one-way valve group has returned to the self-closing state, clean the radon meter probe and store it properly.

[0040] 6. Replace the granular desiccant in the drying part 43 and the dust filter screen on the total outlet pipe 31, and check whether the melt-blown cloth filter screen package 23 of the radium chloride 226 decay chamber 2 needs to be replaced; Clean the glass cavity and metal frame of the sealing chamber 1 to ensure that there is no radioactive contamination left, and complete the calibration process.

[0041] The above detailed description of the present application is combined with specific embodiments and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that the technical solutions and embodiments of the present application can be variously replaced, modified or improved without deviating from the spirit and scope of the present application, and these all fall within the scope of the present application. The protection scope of the present application is subject to the appended claims.

[0042] All publications, patent applications, patents, and other references mentioned in this specification are herein incorporated by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict between the definitions in this specification and that of any incorporated reference, the definition in this specification prevails.

[0043] When the specification states that a material, substance, method, step, apparatus or component etc. is "known to those of ordinary skill in the art," that material, substance, method, step, apparatus or component etc. is known to the skilled artisan at the time that this application is filed, but can or can not have been published or otherwise become known in this art before the filing date of this application.

[0044] In the context of this specification, except as otherwise explicitly indicated, any matter or item not mentioned is directly applicable without any change from those known in the art.

Claims

1. A radon Rn222 measurement chamber for use in the calibration of a radon meter, characterized in that, The utility model relates to a radon measurement device, including: Sealing chamber (1), the sealing chamber (1) is equipped with sealed measurement chamber, both sides of the sealing chamber (1) are equipped with one-way valve group to adjust the air pressure inside the sealed measurement chamber, Radon 226 chloride decay chamber (2), radon 226 chloride decay chamber (2) is equipped in the sealed measurement chamber and is equipped with decay chamber to make radon 226 radioactive decay release radon Rn222, both ends of radon 226 chloride decay chamber (2) are provided with air inlet hole (24) and air outlet hole (25) respectively, Radon measurement instrument assembly (3), radon measurement instrument assembly (3) is equipped in one end of radon 226 chloride decay chamber (2) and is communicated with air outlet hole (25), and radon measurement instrument assembly (3) is equipped with a plurality of radon measurement instruments to measure radon Rn222 released by radon 226 radioactive decay, Air inlet assembly (4), air inlet assembly (4) is equipped in the other end of radon 226 chloride decay chamber (2) and is communicated with air inlet hole (24), and air inlet assembly (4) is equipped with air inlet fan (41) to pass into air in radon 226 chloride decay chamber (2).

2. A radon Rn 222 measurement chamber for use in the calibration of a radon measurement instrument according to claim 1, characterised in that, The one-way valve group includes one-way air inlet valve (11) and one-way air outlet valve (12), and the one-way air inlet valve (11) and the one-way air outlet valve (12) are respectively arranged on the outer circumferential surface of the sealing chamber (1) and are communicated with the sealed measurement chamber, so as to seal the sealed measurement chamber when the sealed measurement chamber is similar to the external pressure, the one-way air inlet valve (11) and the one-way air outlet valve (12) adopt a gravity type self-closing structure, and the valve sheet materials of the one-way air inlet valve (11) and the one-way air outlet valve (12) are all radiation-resistant organic glass materials.

3. A radon Rn 222 measurement chamber for use in the calibration of a radon measurement instrument according to claim 1, characterized in that The radon 226 chloride decay chamber (2) comprises: A shell (21) formed as a stainless steel metal piece and provided with a containing chamber, A shielding inner layer (22) arranged in the containing chamber and connected with the inner wall surface of the shell (21), the shielding inner layer (22) is provided with a decay chamber, A plurality of filter screen packages (23), each of the filter screen packages (23) is arranged in the decay chamber and formed as a melt-blown cloth filter screen piece, and each of the filter screen packages (23) is wrapped with radon 226 chloride.

4. A radon Rn 222 measurement chamber for use in the calibration of a radon meter according to claim 3, characterised in that, The shielding inner layer (22) is made of metal lead sheets with a thickness of not less than 5 mm.

5. A radon Rn 222 measurement chamber for use in the calibration of a radon measurement instrument according to claim 1, characterized in that The radon measurement instrument assembly (3) comprises: A total air outlet pipe (31) communicated with one end of the decay chamber, and a dust filter screen arranged on the total air outlet pipe (31) to filter the gas discharged from the decay chamber, A plurality of branch air outlet pipes (32), each of the branch air outlet pipes (32) is arranged at the other end of the total air outlet pipe (31) and formed as a pipe type piece, and the outer circumferential surface of each of the branch air outlet pipes (32) is provided with a plurality of radon outlet fine holes (33) penetrating along the thickness direction of the pipe wall, A plurality of radon measurement instruments, each of the radon measurement instruments is arranged on the branch air outlet pipe (32) in one-to-one correspondence with each of the radon outlet fine holes (33) to calibrate the radon Rn222 contained in the gas.

6. A radon Rn 222 measurement chamber for use in the calibration of a radon measurement instrument according to claim 1, characterized in that The air inlet assembly (4) comprises: A fan (41) has one end communicating with outside air and is provided with an air inlet filter screen; An air inlet duct (42) has one end communicating with the other end of the fan (41) and the other end communicating with the air inlet hole (24) of the radium226 chloride decay chamber (2); A drying part (43) is arranged on the air inlet duct (42) and is internally provided with a granular desiccant to dry the gas sent into the air inlet duct (42) by the fan (41).

7. A radon Rn 222 measurement chamber for use in the calibration of a radon measurement instrument according to claim 1, characterized in that A main air inlet valve is arranged between the fan (41) and the radium226 chloride decay chamber (2), and a main air outlet valve is arranged between the radium226 chloride decay chamber (2) and the radon detector assembly (3), and the fan (41) communicates with the main air inlet valve and the main air outlet valve.

8. A method for the calibration of a radon Rn222 measurement chamber for the calibration of a radon Rn222 measurement chamber according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: Close the sealed chamber (1) and adjust the one-way valve group to the closed state, start the fan (41) of the air inlet assembly (4), and release radon Rn222 from the radium226 chloride in the radium226 chloride decay chamber (2) by radioactive decay, after the radon concentration is stable, place the radon detector in the sealed chamber (1) for calibration; After the test is completed, open the sealed chamber fan (131) and discharge the radon-containing gas in the sealed measurement chamber through the sealed chamber air inlet valve (132) and the sealed chamber air outlet valve (133).

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