An ionization chamber structure

Abstract

The embodiment of the present application provides an ionization chamber structure, which comprises an incidence assembly, a collection assembly, a pressure reduction ring, a high-voltage electrode, a collection electrode and an adjusting assembly. The incidence assembly comprises an incidence window. The incidence assembly and the collection assembly are arranged at intervals along a height direction. A plurality of pressure reduction rings are arranged along the height direction and are arranged at intervals between the incidence assembly and the collection assembly to form an ionization cavity together with the incidence assembly and the collection assembly. The high-voltage electrode is arranged in the ionization cavity and is located on one side of the incidence assembly. The collection electrode is arranged in the ionization cavity and is located on one side of the collection assembly. The adjusting assembly is connected with the incidence assembly and the collection assembly at opposite ends, respectively, to adjust the interval distance between the incidence assembly and the collection assembly. The ionization chamber structure of the embodiment of the present application has strong versatility.

Description

Technical Field

[0001] This application relates to the field of ionization chamber technology, and in particular to an ionization chamber structure. Background Technology

[0002] With the increasing application of low-energy X-rays, the measurement of their absolute intensity is required in many fields. For example, in medicine and industry, low-energy X-rays have wide applications in radiotherapy, radiodiagnosis, radiation protection, environmental radiation monitoring, and public safety.

[0003] Low-energy X-ray ionizing radiation metrology is fundamental to all these applications, and effective measurement of low-energy X-ray doses ensures the health and safety of workers.

[0004] However, the ionization chamber structure in related technologies has poor environmental adaptability and weak versatility. Summary of the Invention

[0005] In view of this, the main objective of the embodiments of this application is to provide an ionization chamber structure with strong versatility.

[0006] To achieve the above objectives, the technical solution of this application embodiment is implemented as follows:

[0007] This application provides an ionization chamber structure, including:

[0008] An incident component, the incident component including an incident window;

[0009] A collection component, wherein the incident component and the collection component are spaced apart along the height direction;

[0010] Multiple pressure-reducing rings are arranged along the height direction, and the pressure-reducing rings are detachably arranged at the interval between the incident component and the collecting component to form an ionization cavity with the incident component and the collecting component;

[0011] A high-voltage electrode is disposed within the ionization cavity and located on one side of the incident assembly;

[0012] A collecting electrode is disposed within the ionization cavity and located on one side of the collecting assembly;

[0013] An adjustment component is provided, with its two ends connected to the incident component and the collecting component, respectively, to adjust the interval between the incident component and the collecting component.

[0014] In one embodiment, the incident component has a plurality of first connecting holes, each of the first connecting holes being arranged at intervals along the circumference of the incident component; the collecting component has a plurality of second connecting holes, each of the second connecting holes being arranged at intervals along the circumference of the collecting component and corresponding one-to-one with the first connecting holes; the adjusting component includes a plurality of connecting rods and a plurality of adjusting nuts; the connecting rods are movably inserted into the first connecting holes and the second connecting holes; the adjusting nuts are respectively provided at the connection points of the connecting rods with the first connecting holes and the second connecting holes, so as to adjust the interval distance between the incident component and the collecting component by means of the adjusting nuts.

[0015] In one embodiment, the collecting component includes a protective electrode arranged circumferentially around the collecting electrode and spaced apart from it.

[0016] In one embodiment, the high-voltage electrode, the protection electrode, and the voltage-reducing ring are connected in series and electrically connected to the power supply component. The protection electrode and the collecting electrode are at the same potential, while the high-voltage electrode and the collecting electrode have a potential difference.

[0017] In one embodiment, the high-voltage electrode is disposed in a first conductive layer on the side of the incident window near the ionization cavity, and the collecting electrode is disposed in a second conductive layer on the side of the collecting assembly near the ionization cavity.

[0018] In one embodiment, the thickness of the first conductive layer is greater than or equal to 3 mm and less than or equal to 5 mm.

[0019] In one embodiment, a third conductive layer is provided on the inner surface of the pressure reducing ring, and the incident component, the pressure reducing ring, and the collecting component each have an electrical connection hole to electrically connect the first conductive layer, the second conductive layer, and the third conductive layer to the power supply component.

[0020] In one embodiment, the ionization chamber structure includes a resistor, and the resistor is provided between at least one of the high-voltage electrode and the pressure-reducing ring, between adjacent pressure-reducing rings, and between the pressure-reducing ring and the protection electrode. The resistance of the resistor is greater than or equal to 15MΩ and less than or equal to 25MΩ.

[0021] In one embodiment, the incident assembly includes a shielding plate and a fixing plate, wherein a portion of the shielding plate is perforated to form a mounting hole, and the incident window is fixed within the mounting hole by the fixing plate.

[0022] In one embodiment, the incident window is a polyimide film; and / or,

[0023] The shielding plate is a lead plate; and / or,

[0024] The fixing plate is a copper plate.

[0025] This application provides an ionization chamber structure, including an incident component, a collecting component, pressure-reducing rings, a high-voltage electrode, a collecting electrode, and an adjustment component. The incident component includes an incident window. The incident component and the collecting component are spaced apart along the height direction. Multiple pressure-reducing rings are arranged along the height direction and are detachably disposed at the intervals between the incident component and the collecting component to enclose an ionization cavity. The high-voltage electrode is disposed within the ionization cavity and located on one side of the incident component. The collecting electrode is disposed within the ionization cavity and located on one side of the collecting component. The opposite ends of the adjustment component are connected to the incident component and the collecting component, respectively, to adjust the spacing between them. Thus, on the one hand, by adjusting the spacing between the incident component and the collecting component, the ionization chamber can be adjusted according to different energies and types of radiation, improving the versatility of the ionization chamber structure. On the other hand, the pressure-reducing rings at the intervals between the incident component and the collecting component can prevent damage to the ionization chamber structure due to excessive pressure between them when the adjustment component is fixing the incident component and the collecting component. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the ionization chamber structure according to the first embodiment of this application;

[0027] Figure 2 for Figure 1 Cross-sectional view of the intermediate ionization chamber structure;

[0028] Figure 3 This is a schematic diagram of the structure of the incident component according to the second embodiment of this application;

[0029] Figure 4 for Figure 2 Cross-sectional view of the intermediate pressure reducing ring; the shaded area in the figure is the third conductive layer.

[0030] Figure 5 This is a schematic diagram of the ionization chamber structure according to the third embodiment of this application;

[0031] Figure 6 This is a circuit diagram of the ionization chamber structure according to the fourth embodiment of this application;

[0032] Figure 7 This is a layout diagram of the ionization chamber saturation curve measurement experiment according to the fifth embodiment of this application.

[0033] Explanation of reference numerals in the attached figures

[0034] 10. Incident component; 11. Incident window; 10a. First connection hole; 12. High voltage electrode; 13. Shielding plate; 14. Fixing plate; 20. Collection component; 21. Collection electrode; 20a. Second connection hole; 20b. Electrical connection hole; 30. Pressure reducing ring; 41. Connecting rod; 50. Resistor.

[0035] 10. Incident component 10; 11. Incident window 11; 10a. First connecting hole 10a; 12. High voltage electrode 12; 13. Shielding plate 13; 14. Fixing plate 14; 20. Collecting component 20; 21. Collecting electrode 21; 20a. Second connecting hole 20a; 20b. Electrical connecting hole 20b; 30. Pressure reducing ring 30; 41. Connecting rod 41; 50. Resistor 50. Detailed Implementation

[0036] Air kerma is an important parameter for low-energy X-ray dose transfer. This study focuses on low-X-ray air kerma dose determination technology based on the "ionization method".

[0037] When the ionization chamber structure is placed in a pulsed X-ray radiation field, assuming charged particle equilibrium is satisfied, the air kerma energy K of the pulsed X-ray within the sensitive volume of the ionization chamber structure is... pulse With the generation of charge J g Satisfying the Bragg-Grey equation

[0038] Where K is the X-ray air kerma, W is the average energy consumed to produce a pair of ions in the gas; J g Q is the total charge of ions of a certain symbol released per unit mass of gas in the cavity. g J can be obtained through electronic system measurement g =Q g / m g .

[0039] Where, m g The mass m of the gas in the cavity g =V / ρ, where V is the volume of the cavity and ρ is the density of the gas inside the cavity; This is the ratio of the mass collision stopping power of the medium to the mass collision stopping power of the gas that produces charged ionized particles. The medium should be the outer wall of the cavity ionization chamber structure. This value can be obtained from an ICRU report. W is the average energy consumed to produce a pair of ions in the gas, which can also be obtained from an ICRU report. e is the unit ion charge. The ratio of the mass energy absorption coefficient of the cavity gas to that of the outer wall of the ionization chamber structure can be obtained from an ICRU report; Πk i This is a correction factor.

[0040] One embodiment of this application provides an ionization chamber structure; please refer to [link / reference]. Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 6 The ionization chamber structure includes an incident component 10, a collecting component 20, multiple pressure reducing rings 30 arranged along the height direction, a high-voltage electrode 12, a collecting electrode 21, and an adjustment component.

[0041] The incident component 10 includes an incident window 11.

[0042] The incident component 10 and the collecting component 20 are spaced apart along the height direction.

[0043] The pressure reducing ring 30 is detachably disposed at the interval between the incident component 10 and the collecting component 20, so as to enclose the incident component 10 and the collecting component 20 to form an ionization cavity.

[0044] The high-voltage electrode 12 is disposed inside the ionization cavity and is located on one side of the incident assembly 10.

[0045] The collecting electrode 21 is disposed inside the ionization cavity and is located on one side of the collecting assembly 20.

[0046] The two ends of the adjustment component are connected to the incident component 10 and the collecting component 20 respectively to adjust the interval between the incident component 10 and the collecting component 20.

[0047] Specifically, incident component 10 refers to the component in the ionization chamber structure used to allow rays to enter.

[0048] The type of radiation is not limited, but for ease of description, the radiation in the embodiments of this application is X-ray.

[0049] The entrance window 11 refers to the component that allows X-rays to smoothly enter the interior of the ionization chamber structure while reducing the attenuation and scattering of X-rays during their entry into the ionization chamber structure.

[0050] The material of the entrance window 11 is not limited. For example, the entrance window 11 is a polyimide film.

[0051] The collecting component 20 refers to the component in the ionization chamber structure that collects the charge generated by ionization.

[0052] The high-voltage electrode 12 and the collecting electrode 21 can be formed in any way.

[0053] For example, the high voltage electrode 12 is a first conductive layer disposed on the side of the incident window 11 near the ionization cavity, and the collecting electrode 21 is a second conductive layer disposed on the side of the collecting assembly 20 near the ionization cavity.

[0054] Specifically, the first conductive layer has good conductivity and low resistance.

[0055] The method of forming the first conductive layer is not limited. For example, a conductive material can be sprayed onto the side of the incident window 11 near the ionization cavity to form the first conductive layer.

[0056] The thickness of the first conductive layer is not limited, as long as the resistance of the first conductive layer is less than or equal to 5KΩ.

[0057] For example, the thickness of the first conductive layer is greater than or equal to 3 mm and less than or equal to 5 mm. For instance, the thickness of the first conductive layer is 3 mm, 4 mm, or 5 mm. This improves the measurement efficiency of the ionization chamber structure.

[0058] The second conductive layer has good conductivity and low resistance. Therefore, it can significantly improve the ion collection efficiency.

[0059] The method of forming the second conductive layer is not limited. For example, a conductive material can be sprayed onto the side of the collecting component 20 near the ionization cavity to form the second conductive layer.

[0060] There are no restrictions on the type of conductive material. For example, a conductive material can be a graphite-coated conductive paint.

[0061] The pressure reducing ring 30 is arranged along the height direction and can be separately placed at the interval between the incident component 10 and the collecting component 20 to form an ionization cavity after being enclosed with the incident component 10 and the collecting component 20. At the same time, it can also adjust the pressure distribution in the cavity and between the incident component 10 and the collecting component 20, which helps to stabilize the ionization process and ensure that the ionization chamber structure can work stably under different environmental conditions.

[0062] The number of decompression rings 30 is not limited and is adjusted according to the interval between the incident component 10 and the collecting component 20. For example, the number of decompression rings 30 may be two or more.

[0063] The high-voltage electrode 12 is disposed inside the ionization cavity on one side of the incident component 10 and opposite to the collecting electrode 21. The high-voltage electrode 12 is connected to a high-voltage power supply and forms an electric field with the collecting electrode 21, so that ions generated by radiation ionization entering the ionization cavity can move directionally under the action of the electric field.

[0064] The collecting electrode 21 is located on one side of the collecting assembly 20 within the ionization chamber. The collecting electrode 21 collects electrons or ions generated by ionization. By measuring the amount of charge collected on the collecting electrode 21, the radiation dose entering the ionization chamber structure can be measured.

[0065] The materials of the incident component 10, the collecting component 20, and the pressure reducing ring 30 are not limited. For example, the materials of the incident component 10, the collecting component 20, and the pressure reducing ring 30 may be PMMA.

[0066] The adjustment component can adjust the distance between the incident component 10 and the collecting component 20, so that the ionization chamber structure can be adapted to different measurement needs and conditions by changing the size of the internal ionization cavity.

[0067] This application provides an ionization chamber structure, including an incident component 10, a collecting component 20, a pressure reducing ring 30, a high-voltage electrode 12, a collecting electrode 21, and an adjustment component. The incident component 10 includes an incident window 11. The incident component 10 and the collecting component 20 are spaced apart along the height direction. Multiple pressure reducing rings 30 are arranged along the height direction and are detachably disposed at the intervals between the incident component 10 and the collecting component 20 to enclose an ionization cavity with the incident component 10 and the collecting component 20. The high-voltage electrode 12 is disposed within the ionization cavity and located on one side of the incident component 10. The collecting electrode 21 is disposed within the ionization cavity and located on one side of the collecting component 20. The opposite ends of the adjustment component are respectively connected to the incident component 10 and the collecting component 20 to adjust the spacing between them. Thus, by adjusting the spacing between the incident component 10 and the collecting component 20 using the adjustment component, the ionization chamber structure can be adjusted according to different energies and types of radiation, improving the versatility of the ionization chamber structure. On the other hand, by providing a pressure-reducing ring 30 at the interval between the incident component 10 and the collecting component 20, it is possible to prevent damage to the ionization chamber structure caused by excessive pressure between the incident component 10 and the collecting component 20 when the regulating component is fixing them.

[0068] In one embodiment, please refer to Figure 1 and Figure 3 The incident component has multiple first connecting holes 10a, which are arranged at intervals along the circumference of the incident component 10. The collecting component 20 has multiple second connecting holes 20a, which are arranged at intervals along the circumference of the collecting component 20 and correspond one-to-one with the first connecting holes 10a. The adjusting component includes multiple connecting rods 41 and multiple adjusting nuts. The connecting rods 41 are movably inserted into the first connecting holes 10a and the second connecting holes 20a. Adjusting nuts are respectively provided at the connection points of the connecting rods 41 with the first connecting holes 10a and the second connecting holes 20a, so as to adjust the interval distance between the incident component 10 and the collecting component 20. Thus, on the one hand, by adjusting the component, the ionization chamber structure can quickly adjust the distance between the incident component 10 and the collecting component 20 according to different experimental requirements, improving the adaptability and versatility of the equipment. On the other hand, by connecting the connecting rod 41 to the first connecting hole 10a and the second connecting hole 20a, and fixing it with the adjusting nut, a stable mechanical structure is formed. During the use of the ionization chamber structure, the relative positions of the incident component 10 and the collecting component 20 can be kept stable, ensuring the normal operation of the ionization chamber structure.

[0069] Specifically, the first connecting hole 10a refers to a hole structure located on the incident component 10, arranged at intervals along the circumference of the incident component 10, and cooperating with the adjustment component.

[0070] The number of first connecting holes 10a is unlimited.

[0071] The second connection hole 20a is a hole structure located on the collecting component 20. These holes are arranged at intervals along the circumference of the collecting component 20 and correspond one-to-one with the first connection hole 10a. They are used to cooperate with the adjustment component to realize the connection between the incident component 10 and the collecting component 20.

[0072] The number of second connecting holes 20a is unlimited, as long as their number corresponds to the number of first connecting holes 10a.

[0073] The connecting rod 41 can be movably passed through the first connecting hole 10a and the second connecting hole 20a. By adjusting the relative positions of the first connecting hole 10a and the second connecting hole 20a on the connecting rod 41, the interval distance between the incident component 10 and the collecting component 20 can be adjusted.

[0074] The material of the connecting rod 41 is not limited, as long as it has a certain strength and rigidity and can withstand the force generated when adjusting the distance between the incident component 10 and the collecting component 20.

[0075] The number of connecting rods 41 is unlimited, as long as their number corresponds to the number of the first connecting holes 10a.

[0076] An adjusting nut is installed at the connection between the connecting rod 41 and the first connecting hole 10a and the second connecting hole 20a. By rotating the adjusting nut, the positions of the first connecting hole 10a and the second connecting hole 20a on the connecting rod 41 can be changed, thereby adjusting the distance between the incident component 10 and the collecting component 20.

[0077] In one embodiment, the collecting component 20 includes a guard electrode arranged circumferentially around the collecting electrode 21 and spaced apart from it. Thus, by providing the guard electrode, the inhomogeneity of the electric field and the influence of leakage current can be reduced, thereby improving the measurement accuracy of ionizing radiation by the ionization chamber structure.

[0078] Specifically, the guard electrode is arranged circumferentially around the collector electrode 21 and spaced apart from it. That is, the guard electrode is a ring electrode extending circumferentially around the collector electrode 21, and the space between the guard electrode and the collector electrode 21 is a ring-shaped spacer region.

[0079] The width of the protective electrode is not limited and can be determined according to the actual situation.

[0080] There is no strict limit to the spacing between the protection electrode and the collector electrode 21; it can be determined according to the actual situation.

[0081] In one embodiment, please refer to Figure 5 The high-voltage electrode 12, the protective electrode, and the pressure-reducing ring 30 are connected in series and electrically connected to the power supply assembly. The protective electrode and the collecting electrode 21 are at the same potential, while a potential difference exists between the high-voltage electrode 12 and the collecting electrode 21. Therefore, on the one hand, the equal potential of the protective electrode and the collecting electrode 21 avoids inaccurate charge collection caused by uneven electric field or external interference. Ions generated by ionization can smoothly reach the collecting electrode 21 without interference, ensuring the accuracy of radiation dose measurement in the ionization chamber structure. On the other hand, the potential difference between the high-voltage electrode 12 and the collecting electrode 21 generates a stable electric field, providing power for the ionization process.

[0082] Specifically, the equal potential of the guard electrode and the collector electrode 21 means that the guard electrode and the collector electrode 21 have the same potential in the electric field, which can ensure that the collector electrode 21 can accurately collect the charge generated by ionization without being affected by the non-uniformity of the electric field.

[0083] A potential difference is formed between the high-voltage electrode 12 and the collecting electrode 21. The electric field generated by the potential difference is the driving force for the ions generated by ionization to move within the ionization chamber structure. The potential of the high-voltage electrode 12 is greater than that of the collecting electrode 21, thereby enabling ions to move from the high-potential high-voltage electrode 12 to the low-potential collecting electrode 21.

[0084] In one embodiment, please refer to Figure 1 , Figure 2 and Figure 5 A third conductive layer is provided on the inner surface of the pressure reducing ring 30. The incident component 10, the pressure reducing ring 30, and the collecting component 20 each have an electrical connection hole 20b to electrically connect the first, second, and third conductive layers to the power supply component. By providing a third conductive layer on the inner surface of the pressure reducing ring 30 and providing electrical connection holes 20b on the incident component 10, the pressure reducing ring 30, and the collecting component 20, a stable and reliable electrical connection between the first, second, and third conductive layers is achieved. This ensures that the high-voltage electrode 12, the collecting electrode 21, and the pressure reducing ring 30 can obtain a stable power supply, maintains the stability of the electric field within the ionization chamber structure, and guarantees the smooth progress of the ionization and charge collection processes.

[0085] Specifically, the third conductive layer has good conductivity and low resistance.

[0086] The method of forming the third conductive layer is not limited. For example, a conductive material can be sprayed onto the inner surface of the pressure reducing ring 30 to form the third conductive layer.

[0087] The thickness of the third conductive layer is unlimited and can be set according to the actual situation.

[0088] The thickness of the conductive layer affects the response of the master standard, and its adhesion stability determines the long-term stability and general quality characteristics of the master standard. Therefore, the method of spraying the conductive material plays a decisive role in the performance of the conductive layer.

[0089] In one specific embodiment, the method for spraying conductive material includes:

[0090] Step S1: Ultrasonically clean the incident component 10, the collecting component 20 and the pressure reducing ring 30, and wipe them with a lint-free cloth.

[0091] Step S2: Apply the graphite coating conductive paint multiple times to the surface through the nozzle to form a coated surface. The distance between the nozzle and the surface should be greater than or equal to 15cm and less than or equal to 20mm. During the spraying process, the hand should move slowly.

[0092] Step S3: Dry the sprayed surface after spraying.

[0093] Step S4: Repeat steps S2 and S3 to spray the surface 5 times.

[0094] Step S5: After the spraying is completed, place the incident component 10, the collecting component 20 and the pressure reducing ring 30 into the dryer to dry.

[0095] Step S6: Measure the resistance of the sprayed surface after drying. If the resistance of the sprayed surface is greater than 5kΩ, repeat step S5 until the resistance is less than or equal to 5kΩ.

[0096] Electrical connection holes 20b are respectively provided on the incident component 10, the pressure reducing ring 30 and the collecting component 20. They are channels for realizing electrical connections between the components and between the components and the power supply component. By inserting conductive parts (such as wires) through the electrical connection holes 20b, a stable electrical connection can be established.

[0097] In one specific embodiment, the ionization chamber structure includes a connecting component that passes through an electrical connection hole 20b, the inner wall of which is threaded. Therefore, when the connecting component is connected to the electrical connection hole 20b, a more secure connection can be achieved through the threaded engagement, preventing loosening due to vibration or other factors during use.

[0098] In one specific embodiment, a sealing structure is provided around the electrical connection hole 20b. This prevents moisture, dust, and other contaminants from the external environment from entering the connection area and affecting the reliability of the electrical connection.

[0099] Specifically, the sealing structure can be designed as an annular groove into which a sealing ring is embedded, and the sealing ring is sealed to the connecting parts.

[0100] In one specific embodiment, the ionization chamber structure includes a signal processor, the collecting component 20 has a signal connection hole, and the collecting electrode 21 is electrically connected to the signal processor through the signal connection hole.

[0101] In one embodiment, please refer to Figure 5 The ionization chamber structure includes a resistor 50. A resistor 50 is provided at least one of the following: between the high-voltage electrode 12 and the pressure-reducing ring 30; between adjacent pressure-reducing rings 30; and between the pressure-reducing ring 30 and the protective electrode. The resistance of the resistor 50 is greater than or equal to 15 MΩ and less than or equal to 25 MΩ. For example, the resistance of the resistor 50 can be 15 MΩ, 20 MΩ, or 25 MΩ. Therefore, by setting the resistor 50, the electric field strength of each part within the ionization chamber structure is ensured to be within a suitable range, avoiding adverse effects on the ionization and charge collection processes caused by excessively strong or weak electric fields.

[0102] Specifically, the provision of a resistor 50 between the high-voltage electrode 12 and the pressure reducing ring 30, between adjacent pressure reducing rings 30, and between the pressure reducing ring 30 and the protection electrode means that the location and number of resistors 50 are not limited.

[0103] For example, a resistor 50 may be provided only in one of the following: between the high voltage electrode 12 and the voltage reducing ring 30, between adjacent voltage reducing rings 30, and between the voltage reducing ring 30 and the protection electrode.

[0104] For example, resistors 50 are provided in any two of the following locations: between the high voltage electrode 12 and the voltage reducing ring 30, between adjacent voltage reducing rings 30, and between the voltage reducing ring 30 and the protection electrode.

[0105] For example, resistors 50 are provided between the high voltage electrode 12 and the voltage reducing ring 30, between adjacent voltage reducing rings 30, and between the voltage reducing ring 30 and the protection electrode.

[0106] In one embodiment, please refer to Figure 2 The incident component 10 includes a shielding plate 13 and a fixing plate 14. A portion of the shielding plate 13 has openings to form mounting holes, and the incident window 11 is fixed within these mounting holes by the fixing plate 14. Thus, on the one hand, the shielding plate 13 effectively reduces electromagnetic interference and radio frequency interference, ensuring more accurate and reliable measurement results from the ionization chamber structure. On the other hand, fixing the incident window 11 within the mounting holes of the shielding plate 13 using the fixing plate 14 ensures the positional stability of the incident window 11 during the operation of the ionization chamber structure.

[0107] Specifically, the shielding plate 13 is part of the incident assembly 10, and its main function is to block external interference from entering the ionization chamber structure.

[0108] The fixing plate 14 is used to fix the entrance window 11 in the mounting hole of the shielding plate 13. It serves to fix and support the entrance window 11, ensuring that the position of the entrance window 11 is stable during the operation of the ionization chamber structure and maintaining the stability of the radiation entry channel.

[0109] Mounting holes are holes in the shielding plate 13 for mounting the entrance window 11. Their shape, size, and position match the size and shape of the entrance window 11 to achieve a secure installation of the entrance window 11.

[0110] The material of shielding plate 13 is not limited. For example, shielding plate 13 is a lead plate.

[0111] The material of the fixing plate 14 is not limited. For example, the fixing plate is made of copper.

[0112] In one specific embodiment, a saturation characteristic experiment of the ionization chamber structure was conducted.

[0113] Specifically, the saturation curve of an ionization chamber structure refers to the saturation curve of the ionization chamber structure obtained by increasing the polarization voltage applied to the ionization chamber structure from zero under radiation of a certain intensity until the ionization current output by the ionization chamber structure is saturated.

[0114] To test the rationality of the ionization chamber structure assembly, a suitable polarization voltage was selected, and the ionization chamber structure was positioned directly opposite... 137 The Cs-γ irradiation apparatus has its ionization chamber's geometric center 2.5 m from the 137Cs beam exit. The true dose rate at this location is approximately 16.8 μGy / h. The experimental layout is as follows: Figure 7 As shown, a Unidos E electrometer is used as the high-voltage power supply and ionization current measuring device.

[0115] Table 1 records the ionization current values ​​collected by the ionization chamber probe at different voltages. 137 The dose rate output by the Cs-γ irradiation device remains unchanged.

[0116] Table 1 Saturation characteristic experiment

[0117]

[0118]

[0119] As shown in Table 1, the ionization chamber structure enters the saturation region after the voltage exceeds 250V, and its plateau region is relatively wide. Based on the ionization saturation characteristics of air, a polarization voltage of 400V is selected, which is located in the middle of the plateau region.

[0120] In one specific embodiment, leakage current testing is performed using an ionization chamber structure.

[0121] Specifically, the leakage current performance of the ionization chamber structure is related to the performance of the insulation material between the collector and the guard electrode, as well as the cleanliness of the processing equipment. It is an important indicator for evaluating the performance of the ionization chamber structure, especially at low dose rates, where leakage current performance will affect the accurate measurement of ionization current.

[0122] pass 137 The leakage current of the ionization chamber structure was tested using the Cs standard reference radiation field. First, the ionization chamber structure was placed in a sufficiently low background environment to avoid generating a large ionization signal from the background. The ionization chamber structure was connected to the electrometer, and the electrical quantity measurement mode was selected after powering on. A maximum operating voltage of 400V was applied to the ionization chamber structure, and after sufficient preheating, zeroing was performed. The current value was read and the test results were recorded. The average value of the measured results was calculated as the leakage current test result. Using a Unidos E electrometer as the high-voltage power supply and ionization current measurement device, a 400V polarization voltage was applied to the ionization chamber structure, and the leakage current was measured. Table 2 shows that the average value of 10 leakage current measurements was 71.6 fA.

[0123] Table 2 Leakage Current Test of Ionization Chamber Structure

[0124]

[0125]

[0126] In one specific embodiment, the repeatability of the ionization chamber structure is studied through the ionization chamber structure.

[0127] Specifically, an air kerma rate of approximately half the most sensitive range of the instrument under test is selected, and 10 consecutive measurements are performed under the same conditions. The dose rate values ​​measured by the device under test are recorded, and the relative standard deviation is calculated. The specific steps include:

[0128] Step S1: Connect the ionization chamber structure to the UNIDOSE electrometer and input the response parameter N (Gy / C); In the X-ray standard radiation field, use a moving trolley and laser positioning system to place the ionization chamber structure within the uniform irradiation field of the X-ray reference radiation field. The reference point of the ionization chamber structure coincides with the calibration point on the central axis of the irradiation beam. Fix the device under test according to its calibration direction at the known conventional true value K of the air kerma rate. T At the measurement point.

[0129] Step S2: Apply the maximum operating voltage of 400V to the ionization chamber structure of the UNIDOSE electrometer, and perform zeroing operation after preheating.

[0130] Step S3: Measure the background reading K at the measurement point without turning on the irradiation device. IB The recorded reading values ​​shall be no less than 10 times.

[0131] Step S4: Select the conventional true value K of air kerma rate through the X-ray device control system in the main control room. T The corresponding radioactive material.

[0132] Step S5: Open the shielding door of the gamma irradiation device. After stabilizing for 5 minutes, start a set of measurements and record the dose rate. The data should be no less than 10 sets.

[0133] Step S6: Turn off the X-ray irradiation device and select the next conventional true value K for air kerma rate. T The corresponding radiation source was accurately positioned at the measurement point by the mobile calibration vehicle.

[0134] Step S7: Repeat steps S1-S6 to measure and record, as shown in Table 3.

[0135] Table 3 Repeatability Experiments

[0136]

[0137] In one specific embodiment, the linear response measurement of the ionization chamber structure is carried out through the ionization chamber structure.

[0138] Specifically, in 137 Linear response measurements of the ionization chamber structure were conducted in the Cs-γ standard reference radiation field. The ionization chamber structure was directly opposite the beam exit, and the geometric center of the ionization chamber structure was 1 m away from the beam exit of the optomechanical system. The principle is to place the standard instrument at the calibration point of the radiation field, obtain the standard dose value by measurement, and then accurately place the instrument to be calibrated at the same position so that the reference point of the instrument to be calibrated coincides with the calibration point. The instrument reading was obtained by measurement, and the calibration factor was obtained by comparing the two measurement results, as shown in Equation (1).

[0139]

[0140] In the formula, R is the calibration factor for the ionization chamber structure, which is dimensionless; This is the baseline value for the radiation field, expressed in Gy / h. These are the measured values ​​of the ionization chamber structure after temperature and pressure correction, in Gy / h.

[0141] The linear response measurement results of the ionization chamber structure are shown in Table 4.

[0142] Table 4. Measurement results of the linear response of the ionization chamber structure.

[0143]

[0144]

[0145] In one specific embodiment, an N-series X-ray reference radiation mass response experiment is conducted using an ionization chamber structure.

[0146] Specifically, using X-ray N-series reference radiation quality, the calibration factor of the ionization chamber structure was measured in the reference radiation field, and the response at each energy was compared with... 137 The response to the Csγ reference radiation is normalized, and the normalized response value is:

[0147] In the formula, R' E R represents the energy response of the ionization chamber structure, which is dimensionless. E R is the dimensionless calibration factor for the ionization chamber structure at various energies. CS for 137 The calibration factor for the ionization chamber structure of the Cs-γ reference radiation is dimensionless. The energy response measurements of the ionization chamber structure are shown in Table 5.

[0148] Table 5. Experimental Results of Mass-Energy Response to N Series X-ray Reference Radiation

[0149]

[0150] In the description of this application, the references to terms such as "in one embodiment," "in some embodiments," "in a specific embodiment," or "exemplary," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the embodiments of this application. In this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine the different embodiments or examples described in this application, as well as the features of the different embodiments or examples.

[0151] The above description is merely a preferred embodiment of this application and is not intended to limit the application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. An ionization chamber structure, characterized in that, include: An incident component, the incident component including an incident window; A collection component, wherein the incident component and the collection component are spaced apart along the height direction; Multiple pressure-reducing rings are arranged along the height direction, and the pressure-reducing rings are detachably arranged at the interval between the incident component and the collecting component to form an ionization cavity with the incident component and the collecting component; A high-voltage electrode is disposed within the ionization cavity and located on one side of the incident assembly; A collecting electrode is disposed within the ionization cavity and located on one side of the collecting assembly; An adjustment component is provided, with its two ends connected to the incident component and the collecting component, respectively, to adjust the interval between the incident component and the collecting component.

2. The ionization chamber structure according to claim 1, characterized in that, The incident component has multiple first connecting holes, each of which is arranged at intervals along the circumference of the incident component. The collecting component has multiple second connecting holes, each of which is arranged at intervals along the circumference of the collecting component and corresponds one-to-one with the first connecting holes. The adjusting component includes multiple connecting rods and multiple adjusting nuts. The connecting rods are movably inserted into the first connecting holes and the second connecting holes. The adjusting nuts are respectively provided at the connection points of the connecting rods with the first connecting holes and the second connecting holes, so as to adjust the interval distance between the incident component and the collecting component.

3. The ionization chamber structure according to claim 1, characterized in that, The collecting component includes a protective electrode arranged circumferentially around the collecting electrode and spaced apart from it.

4. The ionization chamber structure according to claim 3, characterized in that, The high-voltage electrode, the protection electrode, and the voltage-reducing ring are connected in series and electrically connected to the power supply component. The protection electrode and the collecting electrode are at the same potential, while the high-voltage electrode and the collecting electrode have a potential difference.

5. The ionization chamber structure according to any one of claims 1-3, characterized in that, The high-voltage electrode is disposed in the first conductive layer on the side of the incident window near the ionization cavity, and the collecting electrode is disposed in the second conductive layer on the side of the collecting assembly near the ionization cavity.

6. The ionization chamber structure according to claim 5, characterized in that, The thickness of the first conductive layer is greater than or equal to 3 mm and less than or equal to 5 mm.

7. The ionization chamber structure according to claim 5, characterized in that, The inner surface of the pressure reducing ring is provided with a third conductive layer, and the incident component, the pressure reducing ring and the collecting component are respectively provided with electrical connection holes so that the first conductive layer, the second conductive layer and the third conductive layer are electrically connected to the power supply component.

8. The ionization chamber structure according to claim 3, characterized in that, The ionization chamber structure includes a resistor, and the resistor is provided in at least one of the following: between the high voltage electrode and the pressure reducing ring, between adjacent pressure reducing rings, and between the pressure reducing ring and the protection electrode. The resistance of the resistor is greater than or equal to 15MΩ and less than or equal to 25MΩ.

9. The ionization chamber structure according to any one of claims 1-4, characterized in that, The incident component includes a shielding plate and a fixing plate. A portion of the shielding plate is perforated to form a mounting hole, and the incident window is fixed within the mounting hole by the fixing plate.

10. The ionization chamber structure according to claim 9, characterized in that, The incident window is a polyimide film; and / or, The shielding plate is a lead plate; and / or, The fixing plate is a copper plate.

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