Ionization chamber for Flash radiotherapy

Abstract

The invention provides an ionization chamber for Flash radiotherapy, and the ionization chamber comprises a plurality of ionization chambers, each ionization chamber comprises a high-voltage electrode, a collector and an insulating separator plate, and the insulating separator plate is located between the high-voltage electrode and the collector; and the high-voltage electrode, the collector and the insulating partition plate are attached. According to the ionization chamber for Flash radiotherapy, the technical problems that ion recombination occurs and the edge of the collector and the edge of the high-voltage electrode are tilted to cause short circuit of the ionization chamber in the prior art are solved.

Description

Technical Field

[0001] The invention relates to the technical field of ionizing radiation, and in particular to an ionization chamber used for Flash radiotherapy. Background Art

[0002] Traditional radiotherapy electron beam monitoring uses a thin-window flat-panel ionization chamber. Since the dose rate of conventional electron radiotherapy is low, the gas ion recombination effect in the ionization chamber is not significant, and the conventional radiotherapy time at conventional dose rates is long. Even if there are measurement inaccuracies, there is still a chance to compensate and correct them, which will not affect the entire radiotherapy process. However, in the monitoring application scenarios of ultra-high dose rates and ultra-high doses, the positive and negative ion densities generated by secondary electron radiation ionization are large, and non-negligible ion recombination is likely to occur, making it difficult to accurately monitor the dose rate and dose in the Flash mode. In addition, the ultra-high dose rate Flash radiotherapy treatment time is in the ms level, and there is no trial and error opportunity. Therefore, it is difficult for traditional thin-window flat-panel ionization chambers to ensure the accuracy of Flash radiotherapy parameters and the safety of radiotherapy.

[0003] In order to ensure the accuracy of flash radiotherapy dose rate or dose monitoring, the ionization chamber must meet the following requirements: low electron blocking and low ion recombination. There are corresponding solutions in the world, such as semiconductor or scintillator solutions, but these solutions have to face the radiation damage and cost issues under short-term high-dose irradiation, so the ionization chamber is still the most practical technical route.

[0004] In order to solve the problems of velocity blocking and ion recombination in the flat-plate ionization chamber, it is necessary to reduce the amount of gas medium in the ionization chamber as much as possible, for example, by reducing the distance between the high-voltage electrode and the collector. While reducing the distance, there will be a problem of uniformity of the distance between the electrodes under a small gap to prevent air breakdown or short circuit due to the difference in the distance; similarly, under long-term ultra-high dose rate and high-dose irradiation, the partitioned collector plate installation is prone to radiation damage, and the edge of the collector plate will fall off and warp, affecting the collection efficiency and accuracy, and even the warped collector plate will touch the high-voltage electrode and short-circuit, causing the ionization chamber to fail.

[0005] Therefore, the prior art needs to be further developed. Summary of the invention

[0006] The purpose of the present invention is to overcome the above technical deficiencies and provide an ionization chamber for Flash radiotherapy to solve the technical problems in the related art of ion recombination and the warping of the edges of the collecting electrode and the high-voltage electrode, which easily lead to short circuit in the ionization chamber.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: an ionization chamber for Flash radiotherapy is provided, comprising a plurality of ionization chambers, each of which comprises a high voltage electrode, a collecting electrode and an insulating partition, wherein the insulating partition is located between the high voltage electrode and the collecting electrode; the high voltage electrode, the collecting electrode and the insulating partition are fitted together.

[0008] Further, the ionization chamber includes a first ionization chamber, the first ionization chamber includes a first high-voltage electrode, a first collecting electrode and a first insulating partition, the first insulating partition is located between the first high-voltage electrode and the first collecting electrode; the first collecting electrode includes a first supporting plate and a plurality of first polarization plates, the first polarization plates are located on the side of the first supporting plate close to the first insulating partition; the first high-voltage electrode includes a first high-voltage supporting plate and a first high-voltage part, the first high-voltage part is located on the side of the first high-voltage supporting plate close to the first insulating partition.

[0009] Furthermore, a plurality of first polarization plates are arranged at intervals on the first carrier plate, so that a first gap is formed between two adjacent first polarization plates.

[0010] Furthermore, a first pressing component is provided on the first insulating partition, and the first pressing component and the first gap are provided correspondingly. The first pressing component includes a plurality of first ribs, and each first rib fits and presses the edge of each first polarization plate, so that the edge of the first polarization plate is clamped between the first pressing component and the first supporting plate.

[0011] Furthermore, a second pressing component is provided on the first supporting plate, and the second pressing component is arranged corresponding to the first gap. The second pressing component includes a plurality of second ribs, and each second rib is arranged corresponding to the first gap. The second ribs are connected to the edge of the first polarization plate, so that the edge of the first polarization plate is clamped between the first rib and the second rib.

[0012] Furthermore, the ionization chamber also includes a second ionization chamber, which includes: a second high-voltage electrode, a second collecting electrode and a second insulating partition; the second high-voltage electrode includes a second high-voltage bearing plate and a second high-voltage part, and the second high-voltage part is arranged on the side of the second high-voltage bearing plate close to the second insulating partition; the second insulating partition is located between the second high-voltage electrode and the second collecting electrode; the second collecting electrode includes a second bearing plate and a second polarization plate, and the second polarization plate is located on the side of the second bearing plate close to the second insulating partition; a third pressing component is arranged on the second insulating partition, and the third pressing component includes third ribs, and each third rib is in contact with the second polarization plate; a fourth pressing component is arranged on the second bearing plate, and the fourth pressing component is arranged corresponding to the third pressing component.

[0013] Furthermore, there are multiple second polarization plates, which are symmetrically and spaced apart on the second supporting plate, and a second gap is formed between two adjacent second polarization plates; the third holding component is arranged corresponding to the second gap, and each third rib fits and presses the edge of each second polarization plate, so that the edge of the second polarization plate is clamped between the third holding component and the second supporting plate.

[0014] Furthermore, the fourth pressing component is arranged corresponding to the second gap, and the fourth pressing component includes a plurality of fourth ribs, each of which is arranged corresponding to the second gap, and the fourth ribs connect the edge of the second polarization plate, so that the edge of the second polarization plate is clamped between the third ribs and the fourth ribs.

[0015] Furthermore, the ionization chamber also includes a shell, and two ends of the shell are respectively connected to a front cover and a rear cover, and the front cover and the rear cover encapsulate the first ionization chamber and the second ionization chamber in the shell.

[0016] Furthermore, the first polarization plate, the first high voltage part, the second polarization plate and the second high voltage part are all made of low-Z metal materials; the first bearing plate, the second bearing plate, the first high voltage bearing plate, the second high voltage bearing plate, the first insulating partition and the second insulating partition are all made of inorganic insulating materials.

[0017] Furthermore, the thickness ranges of the first polarization plate, the first high voltage part, the second polarization plate and the second high voltage part are all 10 μm to 100 μm; the thickness ranges of the first insulating separator and the second insulating separator are all 20 μm to 300 μm.

[0018] Beneficial effects: 1. The ionization chamber for flash radiotherapy of the present invention is provided with an insulating partition with a certain thickness between the plates. The thickness of the insulating partition is used to ensure the spacing between the collector and the high-voltage pole, so that the spacing between the plates can be reduced to the required value more easily, and the amount of gas medium between the plates can be reliably and significantly reduced, reducing or avoiding the ion recombination effect; similarly, the problem of the uniformity of the gap between the plates is converted into the problem of the uniformity of the thickness of the insulating partition, which simplifies the problem. The flat plate structure of the insulating partition ensures the uniformity of the spacing between the collector and the high-voltage pole, and prevents air breakdown or short circuit due to the difference in spacing when the spacing is small under the traditional ionization chamber structure.

[0019] 2. In the ionization chamber for Flash radiotherapy of the present invention, the ribs on the insulating partition fit and press the periphery of the polarization plate, eliminating the problem of the polarization plate and the supporting plate being bonded and possibly falling off and warping after long-term irradiation, avoiding the polarization plate and the high-voltage pole from contacting each other and causing a short circuit, thereby ensuring the reliability of the operation of the ionization chamber.

[0020] 3. When the ionization chamber for flash radiotherapy of the present invention is used, both double ionization chambers are recessed inside the shell to avoid touching the surface of the ionization chambers, thereby ensuring the safety of the equipment.

[0021] 4. The ionization chamber for Flash radiotherapy of the present invention is used, and the plates and partitions are designed into annular structures with different diameters, which are stacked, pressed and fitted together, and the structure of the positioning groove is auxiliary designed so that the double ionization chamber is clamped between the front cover and the rear cover, and the connection is firm and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is an exploded view of an ionization chamber for flash radiotherapy used in an embodiment of the present invention; Figure 2 is a schematic structural diagram of a first collector used in an embodiment of the present invention; Figure 3 is a schematic structural diagram of a first pressing component used in an embodiment of the present invention; Figure 4 is a schematic structural diagram of a second collector used in an embodiment of the present invention; Figure 5 is a schematic structural diagram of a third pressing component used in an embodiment of the present invention; Figure 6 is a schematic structural diagram of a first high voltage electrode used in an embodiment of the present invention; Figure 7 It is a structural schematic diagram of an ionization chamber for flash radiotherapy adopted in an embodiment of the present invention from one perspective; Figure 8 It is a schematic structural diagram from another perspective of an ionization chamber for flash radiotherapy adopted in an embodiment of the present invention.

[0023] The above drawings include the following reference numerals: 100, first ionization chamber; 110, first high voltage pole; 111, first high voltage bearing plate; 1111, positioning groove; 112, first high voltage portion; 113, first high voltage level pin; 120, first collector; 121, first bearing plate; 122, first polarization plate; 123, first gap; 124, first collector pin; 130, first insulating partition; 140, second pressing component; 141, second rib; 150, first pressing component; 151, first rib; 200, second ionization chamber; 210, second high voltage pole; 211, second high voltage bearing plate ; 212, second high-voltage part; 220, second collector; 221, second supporting plate; 222, second polarization plate; 223, second gap; 224, second collector pin; 230, second insulating partition; 240, fourth pressing part; 241, fourth rib; 250, third pressing part; 251, third rib; 300, shell; 310, front end cover; 320, rear end cover; 321, second connecting hole; 330, abutment plate; 331, connecting column; 340, annular pressure plate; 341, first fastener; 400, mounting plate; 500, terminal. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0025] According to an embodiment of the present invention, an ionization chamber for flash radiotherapy is provided. Figures 1 to 8 , including multiple ionization chambers, each of which includes a high-voltage electrode, a collecting electrode and an insulating partition, and the insulating partition is located between the high-voltage electrode and the collecting electrode; the high-voltage electrode, the insulating partition, and the collecting electrode are arranged in a close fit to ensure the size and uniformity of the spacing between the high-voltage electrode and the collecting electrode.

[0026] See also Figure 2In the ionization chamber for Flash radiotherapy of this embodiment, a first ionization chamber 100 is included. The first ionization chamber 100 includes a first high-voltage electrode 110, a first collecting electrode 120 and a first insulating partition 130. The first collecting electrode 120 includes a first supporting plate 121 and a plurality of first polarization plates 122. The first polarization plates 122 are located on a side of the first supporting plate 121 close to the first insulating partition 130; the first high-voltage electrode 110 includes a first high-voltage supporting plate 111 and a first high-voltage portion 112. The first high-voltage portion 112 is located on the first high-voltage supporting plate 111 and close to a side of the first insulating partition 130. In this way, when the first high-voltage electrode 110, the first insulating partition 130 and the first collecting electrode 120 are fitted together, that is, the first high-voltage supporting plate 111, the first high-voltage part 112, the first insulating partition 130, the first polarizing plate 122 and the first supporting plate 121 are fitted together, the first insulating partition 130 is arranged between the first high-voltage part 112 and the first polarizing plate 122, thereby ensuring the size of the gap between the two, especially the accuracy of the gap size under the stage of small gap.

[0027] See also Figure 2 In the ionization chamber for flash radiotherapy of the present embodiment, a plurality of first polarization plates 122 are symmetrically and spaced apart on the first carrier plate 121 , so that a first gap 123 is formed between two adjacent first polarization plates 122 .

[0028] See also Figure 2 In the ionization chamber for Flash radiotherapy of the present embodiment, a first pressing component 150 is arranged on the first insulating partition 130, and the first pressing component 150 and the first gap 123 are arranged correspondingly. Each first polarization plate 122 is located on the side of the first supporting plate 121 close to the first insulating partition 130, so that the first gap 123 is located between the first pressing component 150 and the first supporting plate 121. The first pressing component 150 includes a plurality of first ribs 151, and the width of the first ribs 151 is greater than the width of the first gap 123. Each first rib 151 fits and presses the edge of each first polarization plate 122, so that the edge of the first polarization plate 122 is clamped between the first pressing component 150 and the first supporting plate 121.

[0029] In the existing conventional flat-plate ionization chamber, the high-voltage electrode and the collecting electrode are mostly isolated by means of a spacer ring. However, in the Flash mode, the ultra-high dose rate beam can easily cause radiation damage to the polarization plate in the collecting electrode and the edge of the polarization plate. The edge of the polarization plate may warp or fall off, or even the high-voltage part and the polarization plate may short-circuit. Moreover, the ring-shaped spacer ring cannot ensure the size and uniformity of the spacing between the various parts of the plate during installation, especially the uniform spacing of the plates under small gaps, which is extremely sensitive to the results. The present invention uses a plate-shaped insulating partition, which is fitted to ensure that the partition can hold the polarization plate to prevent warping and falling off. Moreover, the plate-shaped structure of the partition can ensure the size and uniformity of the spacing between the plates, thereby ensuring the accuracy of the test results. In order to reduce beam blocking, the present invention hollows out the integral plate structure. For example, in this embodiment, the first insulating partition 130 is hollowed out, and a first pressing component 150 is formed on the first insulating partition 130 to press the edge of the first collecting electrode 120 to prevent warping and falling off.

[0030] See also Figure 1 and Figure 3In accordance with regulatory requirements, this embodiment adopts a dual ionization chamber, wherein the first polarization plates 122 of the first ionization chamber 100 are symmetrically and spaced apart on the first carrier plate 121, and a first gap 123 exists between two adjacent first polarization plates 122. Since the first polarization plates 122 are a thin metal film structure, they are easily lifted up from the edge of the polarization plates after beam irradiation. When the lifted part contacts the first high-voltage pole 110, a short circuit is very likely to occur. In this embodiment, a first pressing component 150 is provided on the first insulating partition 130, and a first rib 151 of the first pressing component 150 is provided corresponding to the first gap 123. That is to say, when the first polarization plate 122 is a structure of four fan-shaped films attached to the first carrier plate 121 (this partition design of the polarization plate is four partitions), the first gap 123 constitutes a cross-shaped gap, and the multiple first ribs 151 of the first holding component 150 constitute a cross-shaped rib. The cross-shaped gap and the cross-shaped rib are set correspondingly, that is, the cross-shaped rib is pressed on the edge of the first polarization plate 122 to prevent the edge of the first polarization plate 122 from warping, avoiding contact between the collecting electrode and the high-voltage electrode or uneven spacing between the plates, and ensuring reliable operation of the ionization chamber. The cross-shaped ribs overlap with the two adjacent first gaps 123, and the cross-shaped ribs are wider than the first gaps 123, thereby pressing the edge of the polarization plate. A first insulating partition 130 with a certain thickness is arranged between the plates, and the thickness of the first insulating partition 130 is used to ensure the spacing between the first high-voltage electrode 110 and the first collecting electrode 120, so that the plate spacing can be easily reduced to a required value, and the amount of gas medium between the plates can be reliably and significantly reduced, thereby reducing or avoiding the ion recombination effect. The ionization chamber of this embodiment solves the technical problems in the related art that ion recombination occurs and the edges of the collecting electrode and the high-voltage electrode are lifted, which easily leads to a short circuit in the ionization chamber.

[0031] Specifically, the structure of the first pressing component 150 is set according to the structure of each first polarization plate 122. The first polarization plate 122 is made of a low atomic number metal material (low Z metal material), such as aluminum, titanium, etc., and the thickness is maintained at 10μm to 100μm. In this way, the penetration of the electron beam is ensured from both the material and thickness aspects, and the electron beam blocking is reduced as much as possible. At the same time, the first pressing component 150 is hollowed out, and only the first rib 151 is left where the edge of the first polarization plate 122 needs to be pressed, which further ensures the penetration of the electron beam. The first high-voltage bearing plate 111 of the first high-voltage pole 110 and the first insulating partition 130 are made of inorganic insulating materials, such as ceramics, mica, glass, etc. Because glass may be broken and injure people, it is preferably ceramics and mica.

[0032] The first supporting plate 121 also adopts a plate-shaped structure. In order to ensure the penetration and beam profile of the beam, refer to Figure 2In the ionization chamber for flash radiotherapy of this embodiment, the first carrier plate 121 is also hollowed out to form a second pressing component 140. The second pressing component 140 is arranged corresponding to the first gap 123. The second pressing component 140 includes a plurality of second ribs 141. Each second rib 141 is arranged corresponding to the first gap 123. The second rib 141 connects the edge of the first polarization plate 122, so that the edge of the first polarization plate 122 is clamped between the first rib 151 and the second rib 141. The second pressing component 140 and the first pressing component 150 are both arranged corresponding to the first gap 123. The edges on both sides of the first polarization plate 122 are clamped by the first rib 151 and the second rib 141, respectively, which effectively prevents the first polarization plate 122 from tilting.

[0033] See also Figure 1 and Figure 5 In the ionization chamber for flash radiotherapy of this embodiment, a second ionization chamber 200 is also included. The second ionization chamber 200 includes: a second high voltage pole 210, a second collector 220 and a second insulating partition 230. The second insulating partition 230 is located between the second high voltage pole 210 and the second collector 220; the second high voltage pole 210 includes a second high voltage bearing plate 211 and a second high voltage portion 212. The second high voltage portion 212 is arranged on the side of the second high voltage bearing plate 211 close to the second insulating partition 230; the second collector 220 includes a second bearing plate 221 and a second polarization plate 222. The second polarization plate 222 is located on the side of the second bearing plate 221 close to the second insulating partition 230. When there is one second polarization plate 222, a fifth pressing component is arranged on the second insulating partition 230. The fifth pressing component includes a fifth rib. Each fifth rib is in contact with the second polarization plate 222. The ribs on the pressing component are distributed in a cross shape and pressed on the second polarization plate 222. A sixth pressing component is disposed on the second carrying plate 221 , and the sixth pressing component is disposed corresponding to the fifth pressing component.

[0034] See also Figure 1 and Figure 5In the ionization chamber for Flash radiotherapy of the present embodiment, there are multiple second polarization plates 222, and the multiple second polarization plates 222 are arranged on the second supporting plate 221 at intervals and symmetrically, so that a second gap 223 is formed between two adjacent second polarization plates 222. A third pressing component 250 is arranged on the second insulating partition 230, and the third pressing component 250 is arranged corresponding to the second gap 223. The multiple second polarization plates 222 are all located on the side of the second supporting plate 221 close to the second insulating partition 230, so that the second gap 223 is located between the third pressing component 250 and the second supporting plate 221. The third pressing component 250 includes a third rib 251, and each third rib 251 fits and presses the edge of each second polarization plate 222, so that the edge of the second polarization plate 222 is clamped between the third pressing component 250 and the second supporting plate 221. Similarly, in another ionization chamber, that is, the second ionization chamber 200 of this embodiment, the third rib 251 and the second supporting plate 221 are on both sides of the second polarization plate 222 to press the edge of the second polarization plate 222 to prevent the second polarization plate 222 from tilting and contacting the second high voltage electrode 210.

[0035] See also Figure 4 In the ionization chamber for flash radiotherapy of the present embodiment, a fourth pressing component 240 is arranged on the second carrier plate 221, and the fourth pressing component 240 is arranged corresponding to the second gap 223. The fourth pressing component 240 includes a plurality of fourth ribs 241, and each fourth rib 241 is arranged corresponding to the second gap 223, and the fourth rib 241 connects the edge of the second polarization plate 222, so that the edge of the second polarization plate 222 is clamped between the third rib 251 and the fourth rib 241. Similarly, the fourth rib 241, the third rib 251 and the second gap 223 are arranged correspondingly, so that the two sides of the second polarization plate 222 are clamped by the fourth rib 241 and the third rib 251, respectively, to prevent the second polarization plate 222 in the second ionization chamber 200 from tilting and contacting the second high voltage pole 210, and further protect and improve the reliability of the ionization chamber.

[0036] In the ionization chamber for Flash radiotherapy of the present embodiment, the multiple first polarization plates 122 in the first ionization chamber 100 can be divided into four partitions, five partitions or one partition in addition to being arranged. The multiple second polarization plates 222 in the second ionization chamber 200 can also be divided into four partitions, five partitions or one partition. The combination of the first ionization chamber 100 and the second ionization chamber 200 is selected according to the use requirements. For example, "four partitions + one partition" or "five partitions + one partition", wherein one partition means that the polarization plate is not divided into a complete plate, and five partitions refer to a circular partition in the middle. At the same time, the first pressing component 150, the second pressing component 140, the third pressing component 250 and the fourth pressing component 240 are arranged correspondingly according to the selected partition structure.

[0037] See also Figure 7 and Figure 8 In the ionization chamber for Flash radiotherapy of this embodiment, the ionization chamber also includes a shell 300, and the two ends of the shell 300 are respectively connected to the front cover 310 and the rear cover 320, and the first ionization chamber 100 and the second ionization chamber 200 are encapsulated in the shell 300 through the front cover 310 and the rear cover 320.

[0038] See also Figure 1 and Figure 8 In the ionization chamber for flash radiotherapy of this embodiment, the first ionization chamber 100 and the second ionization chamber 200 are mounted on the abutment plate 330 in the housing 300 by bolts and an annular pressure plate 340. The rear end cover 320 is connected to the housing 300 to encapsulate the ionization chamber. The abutment plate 330 is at a certain distance from the end surface of the housing 300, and the flange surface of the annular pressure plate 340 is also provided with a flange extending along its own axis. In this way, after the ionization chamber is encapsulated in the housing 300, the ionization chamber is at a certain distance from the front and rear end surfaces, thereby preventing fingers from touching the ionization chamber and improving safety.

[0039] See also Figure 1 and Figure 8 In the ionization chamber for flash radiotherapy of this embodiment, an abutment plate 330 is arranged in the shell 300, and the abutment plate 330 is connected to the first ionization chamber 100, so that the first ionization chamber 100 is recessed in the shell 300. The first ionization chamber 100, the second ionization chamber 200 and the shell 300 are all cylindrical structures. The shell 300 also includes an annular pressure plate 340, which is arranged between the rear end cover 320 and the second ionization chamber 200. A plurality of first connection holes are arranged around the annular pressure plate 340. The ionization chamber also includes a plurality of first fasteners 341, and each first fastener 341 passes through each first connection hole to fix the second ionization chamber 200 and the first ionization chamber 100 on the abutment plate 330. The annular pressing plate 340 fixes the second ionization chamber 200 and the first ionization chamber 100 in the housing 300 through the abutment plate 330. In addition to pressing the multiple components of the ionization chamber together tightly and ensuring the flatness and certain spacing between the plates during assembly, the abutment plate 330 is at a certain distance from the end surface of the housing 300, and the flange surface of the annular pressing plate 340 and its end are also set at a certain distance. In this way, after the ionization chamber is encapsulated in the housing 300, the ionization chamber is at a certain distance from the front and rear end surfaces, preventing fingers from touching the ionization chamber, thereby improving safety.

[0040] See also Figure 1 and Figure 6In the ionization chamber for Flash radiotherapy of this embodiment, the first high-voltage part 112 can be set on the first high-voltage bearing plate 111 by pasting or crimping with inorganic glue. After the first high-voltage part 112 is pasted or crimped with the first high-voltage bearing plate 111, the entire first high-voltage part 112 is mirror-like, ensuring its flatness, which provides a prerequisite for the subsequent guarantee of uniform gap between the collection part and the high-voltage part; and the use of inorganic glue is to ensure that the bonding part has a certain ability to resist radiation damage under ultra-high dose rate electron beam or X-ray beam irradiation. The second high-voltage part 212 is also set on the second high-voltage bearing plate 211 by pasting or crimping with inorganic glue. The second high-voltage part 212 is mirror-like, ensuring its flatness. In order to reduce the blocking effect on the beam, a through hole for the beam to pass through is opened in the middle of the first high-voltage bearing plate 111 and the second high-voltage bearing plate 211, and its overall shape is annular. The outer diameters of the first high-voltage part 112, the second high-voltage bearing plate 211, and the annular pressure plate 340 are equal, and the outer diameters of the first insulating partition 130, the first bearing plate 121, the second bearing plate 221, and the second insulating partition 230 are consistent. Multiple components are designed to the same size, which facilitates subsequent processing and assembly.

[0041] In addition, when the first fastener 341 is crimped, the pins on the second high voltage part 212 and the first high voltage pins 113 on the first high voltage part 112 are arranged in a staggered manner, and finally connected to the subsequent electronic module through the terminal 500 through the lead wire.

[0042] See also Figure 1 In the ionization chamber for flash radiotherapy of this embodiment, a plurality of connecting posts 331 are arranged on the abutment plate 330, a plurality of second connecting holes 321 are arranged on the rear end cover 320, and each connecting post 331 and each second connecting hole 321 are arranged one-to-one. The ionization chamber also includes a plurality of second fasteners, and the second fasteners pass through the second connecting holes 321 and are connected with the connecting posts 331, so that the rear end cover 320 is connected to the housing 300. A plurality of positioning grooves 1111 are arranged on the first high-voltage bearing plate 111, and each positioning groove 1111 is arranged one-to-one with each connecting post 331. When the rear end cover 320 is connected to the abutment plate 330, the first high-voltage pole 110 is connected to the abutment plate 330. The pole plate and the partition are first designed into annular structures with different diameters, which are connected in a ring, and then the rear end cover 320 is connected to the abutment plate 330 by passing the second fastener through the second connecting hole 321, so as to realize the packaging of the ionization chamber. The annular pressing plate 340 presses the components between the abutting plate 330 and the annular pressing plate 340 onto the abutting plate 330 through a bolt assembly, thereby encapsulating the first ionization chamber 100 and the second ionization chamber 200 in the housing 300 .

[0043] In the ionization chamber for flash radiotherapy of this embodiment, the first polarization plate 122, the first high voltage part 112, the second polarization plate 222 and the second high voltage part 212 are all made of low-Z metal materials; the first carrier plate 121, the second carrier plate 221, the first high voltage carrier plate 111, the second high voltage carrier plate 211, the first insulating partition 130 and the second insulating partition 230 are all made of inorganic insulating materials, preferably ceramic or mica. The thickness of the first polarization plate 122, the first high voltage part 112, the second polarization plate 222 and the second high voltage part 212 is selected in the range of 10μm to 100μm; the thickness of the first insulating partition 130 and the second insulating partition 230 is selected in the range of 20μm to 300μm.

[0044] Detailed description is made according to the direction of electron beam movement. The first ionization chamber 100 is far from the beam exit end, and the second ionization chamber 200 is close to the beam exit end. The first ionization chamber 100 includes a first high-voltage carrier plate 111, a first high-voltage portion 112, a first insulating partition 130 for insulation, a first polarization plate 122, and a first carrier plate 121 in the direction of the electron beam. In order to reduce the blocking and absorption of the beam, the first high-voltage portion 112 is a low-Z metal material or a Mylar film containing a low-Z metal layer, which is directly glued to the first high-voltage carrier plate 111 with an inorganic adhesive. The first polarization plate 122 is also a low-Z metal material or a Mylar film containing a low-Z metal layer, which is also directly glued to the first carrier plate 121 with an inorganic adhesive, so that the first high-voltage portion 112 and the first polarization plate 122 are smooth mirror surfaces after being glued. The thickness of the low-Z metal coating on the low-Z metal material or Mylar film is 10μm to 100μm. There are four first polarization plates 122, and the first gap 123 between each first polarization plate 122 is 1 mm. Each first polarization plate 122 has an independent pin, namely, a first collector pin 124 (such as Figure 2As shown). In the ionization chamber, the traditional isolating ring is replaced with a first insulating isolating plate 130 containing ribs. One of its functions is that the first insulating isolating plate 130 is pressed together by bolts and annular pressing plates to ensure that the gap between the first high-voltage part 112 and the first polarization plate 122 is uniform, thus avoiding short circuit or air breakdown caused by uneven gaps during use. The second function is that the gap can be adjusted by adjusting the thickness of the first insulating isolating plate 130, which changes from ensuring the size and uniformity of the gap through assembly to ensuring the size adjustment and uniformity of the gap through precision machining of the first insulating isolating plate 130, thus reducing the difficulty of assembly and improving the accuracy of key product parameters. The thickness of the first insulating isolating plate 130 ranges from 20 μm to 300 μm. Its third function: the ribs of the first insulating partition 130 correspond to the first gap 123 between adjacent first polarization plates 122 in the collecting plate, and the first ribs 151 and the second ribs 141 cooperate to clamp, fit and press the edges of the first polarization plates 122 that constitute the gap, ensuring that the edges of the first polarization plates 122 will not warp up under long-term beam irradiation, thereby avoiding high and low voltage short circuits.

[0045] The second ionization chamber 200 includes, in order, a second carrier plate 221, a second polarization plate 222, a second insulating partition 230 for insulation, a second high-voltage portion 212, and a second high-voltage carrier plate 211, according to the forward direction of the electron beam. The second high-voltage portion 212 and the second polarization plate 222 are also made of low-Z metal material or Mylar film coated with a low-Z metal layer, and are directly bonded together with inorganic adhesive. The thickness of the low-Z metal coating on the low-Z metal material or Mylar film is 10μm to 100μm. The thickness of the second insulating partition 230 ranges from 20μm to 300μm. The second gap 223 between adjacent second polarization plates 222 is 1mm. Each second polarization plate 222 has an independent pin, namely a second collector pin 224 (such as Figure 4 Each collecting electrode and high voltage electrode are connected to an electrometer (ie, an electronics module) via terminal 500.

[0046] In order to minimize the electron beam loss, the first high voltage carrier plate 111 and the second high voltage carrier plate 211 are designed as annular, that is, the middle electron beam area is designed as a through hole. In this way, the corresponding high voltage parts can only be laminated by lamination.

[0047] The first insulating partition 130, the first supporting plate 121, the second supporting plate 221, and the second insulating partition 230 must take into account both the minimization of electron beam loss and the spatial flatness of the collector, and are designed as a cross-shaped hollow structure (this hollow structure corresponds to the first pressing component 150, the second pressing component 140, the fourth pressing component 240, and the third pressing component 250). The first pressing component 150, the second pressing component 140, the fourth pressing component 240, and the third pressing component 250 are specifically cross-shaped ribs, each of which is composed of a plurality of ribs (correspondingly, the first rib 151, the second rib 141, the fourth rib, and the third rib 251), and the ribs overlap with the gaps between adjacent polar plates, and the ribs are wider than the gaps between polar plates. In this embodiment, each rib is 5 mm wide. During assembly, the cross ribs on each component should overlap. The first carrier plate 121 , the second carrier plate 221 , the first high-voltage carrier plate 111 , the second high-voltage carrier plate 211 , the first insulating spacer 130 and the second insulating spacer 230 are all made of inorganic insulating materials, preferably ceramic or mica.

[0048] In order to ensure that the high-voltage pole and collecting pole of the mirror are not easily touched, which would damage the uniformity of the mirror or the gap, and to avoid leakage current after touching, the double ionization chamber is provided with a shell 300, a front cover 310 and a rear cover 320 on the outside, so that the middle of the ionization chamber is sunken relative to the front and rear covers. The shell 300, the front cover 310 and the rear cover 320 are all annular in design to avoid blocking the electron beam. In order to ensure the flatness of the coating during assembly, an annular pressure plate 340 is also designed, and finally the entire ionization chamber is installed on the radiotherapy head through the mounting plate 400. At the same time, in terms of preventing leakage current, each component should be ultrasonically cleaned before assembly, especially the high-voltage part, the polarization plate, and the insulating partition.

[0049] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0050] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and this embodiment will not be described in detail here.

[0051] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0052] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0053] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. An ionization chamber for flash radiotherapy, characterized in that: It comprises a plurality of ionization chambers, each of which comprises a high voltage electrode, a collecting electrode and an insulating partition, wherein the insulating partition is located between the high voltage electrode and the collecting electrode; the high voltage electrode, the insulating partition and the collecting electrode are arranged in close contact.

2. The ionization chamber for flash radiotherapy according to claim 1, characterized in that: The ionization chamber comprises a first ionization chamber (100), the first ionization chamber (100) comprising a first high-voltage electrode (110), a first collecting electrode (120) and a first insulating partition (130), the first collecting electrode (120) comprising a first supporting plate (121) and a plurality of first polarization plates (122), the first polarization plates (122) being located on a side of the first supporting plate (121) close to the first insulating partition (130); the first high-voltage electrode (110) comprising a first high-voltage supporting plate (111) and a first high-voltage portion (112), the first high-voltage portion (112) being located on a side of the first high-voltage supporting plate (111) close to the first insulating partition (130).

3. The ionization chamber for flash radiotherapy according to claim 2, characterized in that: A plurality of the first polarization plates (122) are symmetrically arranged at intervals on the first carrier plate (121), so that a first gap (123) is formed between two adjacent first polarization plates (122).

4. The ionization chamber for flash radiotherapy according to claim 3, characterized in that: A first pressing component (150) is provided on the first insulating partition (130), the first pressing component (150) and the first gap (123) being provided correspondingly, the first pressing component (150) comprising a plurality of first ribs (151), each of the first ribs (151) being fitted and pressed against an edge of each of the first polarization plates (122), so that the edge of the first polarization plate (122) is clamped between the first pressing component (150) and the first supporting plate (121).

5. The ionization chamber for flash radiotherapy according to claim 4, characterized in that: A second pressing component (140) is provided on the first supporting plate (121), the second pressing component (140) being arranged corresponding to the first gap (123), the second pressing component (140) comprising a plurality of second ribs (141), each of the second ribs (141) being arranged corresponding to the first gap (123), the second ribs (141) being connected to an edge of the first polarization plate (122), so that the edge of the first polarization plate (122) is clamped between the first rib (151) and the second rib (141).

6. The ionization chamber for flash radiotherapy according to claim 2, characterized in that: The ionization chamber further comprises a second ionization chamber (200), the second ionization chamber (200) comprising: a second high-voltage electrode (210), a second collecting electrode (220) and a second insulating partition (230); the second high-voltage electrode (210) comprises a second high-voltage bearing plate (211) and a second high-voltage portion (212), the second high-voltage portion (212) being arranged on a side of the second high-voltage bearing plate (211) close to the second insulating partition (230); the second collecting electrode (220) comprises a second bearing plate (221) and a second polarization plate (222); the second polarization plate (222) is arranged on a side of the second bearing plate (221) close to the second insulating partition (230); A third pressing component (250) is arranged on the second insulating partition (230), the third pressing component (250) comprising third ribs (251), each of the third ribs (251) being in contact with the second polarization plate (222), and a fourth pressing component (240) is arranged on the second supporting plate (221), the fourth pressing component (240) being arranged correspondingly to the third pressing component (250).

7. The ionization chamber for flash radiotherapy according to claim 6, characterized in that: There are a plurality of second polarization plates (222), the plurality of second polarization plates (222) are symmetrically and spaced apart on the second carrier plate (221), and a second gap (223) is formed between two adjacent second polarization plates (222); The third pressing component (250) is arranged corresponding to the second gap (223), and each of the third ribs (251) fits and presses the edge of each of the second polarization plates (222), so that the edge of the second polarization plate (222) is clamped between the third pressing component (250) and the second supporting plate (221).

8. The ionization chamber for flash radiotherapy according to claim 7, characterized in that: The fourth pressing component (240) is arranged corresponding to the second gap (223), the fourth pressing component (240) comprises a plurality of fourth ribs (241), each of the fourth ribs (241) being arranged corresponding to the second gap (223), the fourth ribs (241) being connected to the edge of the second polarization plate (222), so that the edge of the second polarization plate (222) is clamped between the third rib (251) and the fourth rib (241).

9. The ionization chamber for flash radiotherapy according to claim 1, characterized in that: The ionization chamber further comprises a shell (300), two ends of the shell (300) being respectively connected to a front cover (310) and a rear cover (320), and the front cover (310) and the rear cover (320) encapsulate the ionization chamber in the shell (300).

10. The ionization chamber for flash radiotherapy according to claim 6, characterized in that: The first polarization plate (122), the first high-voltage portion (112), the second polarization plate (222) and the second high-voltage portion (212) are all made of low-Z metal materials; the first bearing plate (121), the second bearing plate (221), the first high-voltage bearing plate (111), the second high-voltage bearing plate (211), the first insulating spacer (130) and the second insulating spacer (230) are all made of inorganic insulating materials.

11. The ionization chamber for flash radiotherapy according to claim 6, characterized in that: The thickness of the first shunt plate (122), the first high-voltage portion (112), the second shunt plate (222) and the second high-voltage portion (212) are all within a range of 10 μm to 100 μm; the thickness of the first insulating spacer (130) and the second insulating spacer (230) are all within a range of 20 μm to 300 μm.

Images