A beta particle beam current measuring device

Abstract

The invention provides a beta particle beam current measuring device, which comprises an anode plate, wherein a metal spacer ring, a secondary ionization plate and a first insulating film are stacked on one plate surface of the anode plate to form a secondary ionization chamber, and a main ionization plate, a second insulating film and a main ionization plate pressure ring are stacked on the other plate surface to form a main ionization chamber; a uniform filtering device is arranged on the main ionization plate pressure ring through a plastic spacer ring, and the uniform filtering device comprises a uniform block pressure ring, a third insulating film and a fourth insulating film with a uniform block in the middle, which is stacked on the plastic spacer ring; the main ionization chamber, the secondary ionization chamber and the uniform filtering device are fixed between a top cover and a bottom plate, and the top cover is provided with a plurality of terminals plugged into the secondary ionization, the anode plate and the main ionization plate; the secondary ionization plate, the main ionization plate, the anode plate, the first insulating film, the second insulating film, the third insulating film and the fourth insulating film are all made of polyurethane.

Description

Technical Field

[0001] The invention relates to the technical field of ray measuring devices, and in particular to a beta particle beam measuring device. Background Art

[0002] β-particle beam, also known as β-ray, is a high-speed charged particle with much lower ionization ability than α-ray, but greater penetration ability than α-ray. However, compared with X-ray and γ-ray, β-ray has a shorter range than X-ray and is easily absorbed by materials such as aluminum foil and organic glass. However, when it enters human tissue and skin, it can produce biothermal effect with biological cells and kill cell tissues. Because of this characteristic of β-ray, this ray is used in medicine to treat tumors and cell hyperplasia in the skin and superficial parts. β-ray is a double-edged sword that can kill both tumor cells and normal tissue cells. How to use it for targeted and quantitative treatment of human solid tumors has always been a difficult problem.

[0003] β rays are negatively charged electron beams, which are easily blocked by materials such as organic glass. Therefore, it is necessary to select an electrode substrate that can measure the size of the generated ray beam under the action of the electric field and reduce the dose loss during the penetration of β rays. At the same time, the substrate material is easy to denature when working in a ray environment for a long time, which affects the service life of the detection device. Therefore, it is necessary to find a substrate material that can reduce the dose loss and have excellent radiation resistance. In the past, it was difficult for traditional measurement devices to have both advantages at the same time, so they could only give up one of them. At present, most of them use the method of reducing the service life to improve the measurement accuracy. The disadvantage is that they need to be replaced 2-4 times during the service life of the equipment. There are also traditional β particle beam measurement devices, which use oily lacquer silk as the base material to spray the electrode as the electrode absorption material. It is highly sensitive to temperature, humidity, and pressure. The reason is that in a humid environment, the base material of oily lacquer silk has a certain water absorption, and the different air pressure and temperature can easily cause the measurement electrode to deform, causing measurement accuracy. The method of dealing with this is usually to add a temperature sensor compensation circuit to the back-end processing circuit, which is more cumbersome.

[0004] In summary, the existing β-particle beam measurement devices have the disadvantages of short life, low measurement accuracy, and being easily affected by external conditions. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a β particle beam current measuring device, the purpose of which is to solve the problems that the existing β particle beam current measuring device has a short life, low measurement accuracy and is easily affected by external conditions.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0007] Provided is a beta particle beam current measuring device, comprising an anode plate, wherein a metal spacer ring, a secondary ionization plate and a first insulating film are stacked on one plate surface of the anode plate to form a secondary ionization chamber, and a main ionization plate, a second insulating film and a main ionization plate pressure ring are stacked on the other plate surface to form a main ionization chamber;

[0008] A uniform filtering device is arranged on the main ionization plate pressure ring through a plastic spacer ring, and the uniform filtering device comprises a uniform block pressure ring superimposed on the plastic spacer ring, a third insulating film and a fourth insulating film with a uniform block in the middle;

[0009] The main ionization chamber, the secondary ionization chamber and the leveling filter device are fixed between the top cover and the bottom plate, and the top cover is provided with a plurality of terminals plugged into the secondary ionization, the anode plate and the main ionization plate;

[0010] The secondary ionization plate, the main ionization plate, the anode plate, the first insulating film, the second insulating film, the third insulating film and the fourth insulating film are all made of polyurethane.

[0011] Furthermore, a first conductive layer in the middle and an annular conductive layer of N 1 / N circular rings symmetrically arranged around the first conductive layer are arranged on the front plate surface of the secondary ionization plate, and the metal spacer rings are not in contact with the annular conductive layer;

[0012] The secondary ionization plate outside the annular conductive layer is provided with M first through holes respectively matched with the M first terminals, and the first lead layer of the first conductive layer and the second lead layers of the N annular conductive layers are respectively connected with the M first through holes; there are gaps between the first conductive layer and the annular conductive layer and between adjacent annular conductive layers; wherein M=N+1;

[0013] A second conductive layer is arranged on the sub-plate surface of the secondary ionization plate.

[0014] The areas of the first conductive layer and each annular conductive layer are equal.

[0015] Furthermore, a first annular groove is provided on both surfaces of the anode plate, a third conductive layer is provided on the surface of the anode plate located in the first annular groove, and two second through holes and a third through hole are provided on the anode plate located outside the first annular groove; the two second through holes are connected to the third conductive layer on one side of the plate surface, and the two third through holes are connected to the third conductive layer on the other side of the plate surface, one of the second through holes and one of the third through holes are connected by a wire, and the other second through hole and the other third through hole are respectively connected with second terminals connected to the positive pole of the power supply.

[0016] Furthermore, a second annular groove is provided on the front surface of the main ionization plate, a fourth conductive layer is provided on the main ionization plate located in the second annular groove, and a fourth through hole cooperating with the third terminal is provided on the main ionization plate located outside the second annular groove;

[0017] A fifth conductive layer is arranged on the auxiliary plate surface of the main ionization plate.

[0018] Furthermore, the second conductive layer and the fifth conductive layer are both connected to the negative electrode of the power supply.

[0019] The beneficial effects of the present invention are as follows: In this scheme, polyurethane material is used as the base material, which has strong radiation penetration and radiation resistance. According to the above characteristics, the device only needs to be assembled and welded in dry air under normal atmospheric pressure, thereby ensuring that the life cycle of the device will not be shortened due to the degeneration of the base material. In addition, the surface of the polyurethane material is oily, does not absorb water, has excellent ductility, and has strong tensile strength. The conductive layer is sprayed on it, and has very strong adhesion and is not easy to deform.

[0020] The first insulating film and the second insulating film provided in the device make the secondary ionization chamber and the main ionization chamber in a semi-closed state, reduce external interference, and are less affected by temperature, humidity and air pressure. Under the condition that the test conditions remain unchanged, the device greatly improves the test accuracy and service life.

[0021] The main ionization plate pressure ring can reduce the deformation caused by temperature, humidity and pressure, and increase the measurement accuracy. At the same time, the main ionization chamber and the secondary ionization chamber can be integrated with the uniform filtering device, which has a simple structure and is easy to install. The secondary ionization chamber can determine the uniformity and symmetry of the beta ray quality in a plane by the amount of beta beam electrons collected under the action of the electric field.

[0022] In addition to the technical problems solved by the present invention, the technical features that constitute the technical solution, and the beneficial effects brought about by the technical features of the technical solution described above, the present invention provides other technical problems that can be solved, other technical features included in the technical solution, and the beneficial effects brought about by these technical features, which will be further described in detail in the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 The figure is a schematic diagram of an explosion of a beta particle beam measurement device in the present invention.

[0025] Figure 2 Schematic diagram of the positive plate structure of the secondary ionization plate.

[0026] Figure 3 and Figure 4 Schematic diagram of the structure of the two surfaces of the anode plate.

[0027] Figure 5Schematic diagram of the structure of the positive plate surface of the column ionization plate.

[0028] Wherein: 1. top cover; 2. first insulating film; 3. secondary ionization plate; 301. first through hole; 302. annular conductive layer; 303. first conductive layer; 4. metal spacer ring; 5. anode plate; 501. third conductive layer; 502. first ring groove; 503. second through hole; 504. third through hole; 6. main ionization plate; 601. fourth conductive layer; 602. fourth through hole; 603. second ring groove; 7. main ionization plate pressure ring; 8. plastic spacer ring; 9. leveling block pressure ring; 10. third insulating film; 11. leveling block; 12. fourth insulating film; 13. bottom plate; 14. first terminal; 15. second terminal; 16. third terminal. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and understandable, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0030] Please refer to Figure 1-Figure 5 The present invention provides a beta particle beam current measuring device, which includes an anode plate 5, a metal spacer ring 4, a secondary ionization plate 3 and a first insulating film 2 stacked on one plate surface of the anode plate 5 to form a secondary ionization chamber, and a main ionization plate 6, a second insulating film and a main ionization plate pressure ring 7 stacked on the other plate surface to form a main ionization chamber. A uniform filtering device is arranged on the main ionization plate pressure ring 7 through a plastic spacer ring 8, and the uniform filtering device includes a uniform block pressure ring 9 stacked on the plastic spacer ring 8, a third insulating film 10 and a fourth insulating film 12 with a uniform block 11 in the middle.

[0031] The main ionization chamber, the secondary ionization chamber and the leveling filter device are fixed between the top cover 1 and the bottom plate 13. The top cover 1 is provided with a plurality of terminals plugged into the secondary ionization plate 3, the anode plate 5 and the main ionization plate 6. The secondary ionization plate 3, the main ionization plate 6, the anode plate 5, the first insulating film 2, the second insulating film, the third insulating film 10 and the fourth insulating film are all made of polyurethane.

[0032] The front surface of the secondary ionization plate 3 is provided with a first conductive layer 303 located in the middle and an annular conductive layer 302 with N 1 / N circular rings symmetrically arranged around the first conductive layer 303, and the metal spacer ring 4 is not in contact with the annular conductive layer 302; the secondary ionization plate 3 outside the annular conductive layer 302 is provided with M first through holes 301 respectively matched with M first terminals 14, and the first lead layer of the first conductive layer 303 and the second lead layers of the N annular conductive layers 302 are respectively connected with the M first through holes 301; there are gaps between the first conductive layer 303 and the annular conductive layer 302 and the adjacent annular conductive layers 302; wherein M=N+1, preferably N=4, M=5. The secondary ionization plate 3 is provided with a second conductive layer. The area of ​​the first conductive layer (303) and each annular conductive layer (302) is equal.

[0033] The gap can avoid interference between the first conductive layer 303 and the annular conductive layer 302, ensuring that the electrons are evenly distributed in the secondary ionization chamber. The evenly distributed and symmetrically arranged first conductive layer 303 and annular conductive layer 302 are used to monitor the symmetry and uniformity of the beta particle beam in real time.

[0034] A first annular groove 502 is provided on both plate surfaces of the anode plate 5, a third conductive layer 501 is provided on the anode plate 5 located in the first annular groove 502, and two second through holes 503 and a third through hole 504 are provided on the anode plate 5 located outside the first annular groove 502; the two second through holes 503 are connected to the third conductive layer 501 on one side of the plate surface, and the two third through holes 504 are connected to the third conductive layer 501 on the other side of the plate surface, one of the second through holes 503 and one of the third through holes 504 are connected by a wire, and the other second through hole 503 and the other third through hole 504 are respectively plugged with a second terminal 15 connected to the positive pole of the power supply.

[0035] A second annular groove 603 is provided on the front surface of the main ionization plate 6, a fourth conductive layer 601 is provided on the main ionization plate located in the second annular groove 603, and a fourth through hole 602 matching with the third terminal 16 is provided on the main ionization plate located outside the second annular groove 603. A fifth conductive layer is provided on the secondary surface of the main ionization plate 6.

[0036] The second conductive layer and the fifth conductive layer are both connected to the negative electrode of the power supply.

[0037] In this solution, the secondary ionization plate 3, the metal spacer ring 4, and the solar calendar plate are also provided with through holes for facilitating the insertion of the second terminal 15 or the third terminal 16 or both. The through holes are only for facilitating the second terminal 15 to pass through and connect to the solar calendar plate; or the third terminal 16 to pass through and connect to the main ionization plate 6. The plate surface close to the anode plate 5 is the positive plate surface, and the plate surface away from the anode plate 5 is the secondary plate surface. The terminals include the first terminal 14, the second terminal 15, and the third terminal 16.

[0038] The first insulating film 2 is set to prevent the outside world from directly contacting the second conductive layer, and its thickness is 0.05mm. The secondary ionization plate 3 is used as a substrate to facilitate the uniform laying of the first conductive layer 303, the second conductive layer and the annular conductive layer, so that the secondary ionization plate 3 made of polyurethane is tightly stretched and stretched, and evenly stressed. The metal spacer ring 4 is used to press the secondary ionization plate 3 chamber, and it is also convenient to weld the terminal on the anode plate 5, so that there is a certain space gap between the secondary ionization plate 3 and the anode plate 5, which is convenient for the directional movement and collection of the beta particle beam in the electric field of the secondary ionization chamber. The main ionization plate, the main ionization chamber is used to collect the charged electrons of the beta particle beam and introduce them into the measurement circuit to form a current, so as to determine the dose size of the beta particle beam. The main ionization plate pressure ring 7 and the second insulating film are used to fit the main ionization plate 6; the second insulating film can also prevent the outside world from directly contacting the fifth conductive layer, affecting the measurement accuracy. The plastic spacer ring 8 isolates the main ionization chamber from the leveling filter device. The equalizer block pressure ring 9, the fourth insulating film 12 and the third insulating film 10 are used together to fix the equalizer block 11. The fourth insulating film 12 and the third insulating film 10 are made of polyurethane material to facilitate the penetration of the β particle beam, and the ductility can also be used to fix the equalizer block 11, etc. The material of the equalizer block 11 is high-purity aluminum; due to the characteristics of the β particle beam, the equalizer block 11 can block the higher β particle beam at the center, so that the β rays on the overall radiation circular plane of the fourth insulating film 12 and the equalizer block 11 are evenly distributed.

[0039] The second conductive layer of the secondary ionization plate 3 , the fifth conductive layer of the primary ionization plate 6 and the two third conductive layers 501 of the anode plate 5 can form a constant electric field.

[0040] This solution uses polyurethane material, which makes the device less affected by temperature and humidity, and improves the measurement accuracy; since the polyurethane material has the characteristics of tensile strength, ductility and anti-aging, the service life of the device is increased.

[0041] The top cover 1 and the bottom plate 13 adopt a semi-enclosed structure to make the secondary ionization chamber, the main ionization chamber and the leveling filter device integrated. Specifically, a plurality of bolts are sequentially inserted through the secondary ionization plate 3, the metal spacer ring 4, the anode plate 5, the main ionization plate 6, the main ionization plate pressure ring 7, the plastic spacer ring 8, the leveling block pressure ring 9, the third insulating film 10, the fourth insulating film 12 with the leveling block 11 in the middle and the bottom plate 13 to realize the fixed installation of the secondary ionization chamber, the main ionization chamber and the leveling filter device.

[0042] Since high-energy beta particle beams cannot directly cause ionization, ionization requires the loss of energy through photoelectric absorption, Compton scattering and electron pair generation to produce secondary electrons to ionize the air; secondary electrons are the main cause of real ionization of the air. Beta rays or primary electrons first produce secondary electrons when interacting with the gas. As an ionization chamber, the secondary electrons that enter the air cavity of the ionization chamber are mainly produced in the walls of the ionization chamber.

[0043] When the device is in use, the high-energy beta particle beam emitted by the accelerator is incident from the auxiliary plate surface of the secondary ionization plate into the secondary ionization chamber, and generates excited electrons with the conductive layer of the secondary ionization plate 3. The main ionization plate 6 or the secondary ionization plate 3 and the anode ionization plate generate a constant electric field in the main ionization chamber or the secondary ionization chamber under the constant current DC power supply. The ionized positive and negative ion pairs move in a directional manner under the action of the constant electric field to form a current. The first terminal 14 and the third terminal 16 are connected to any detection circuit through BNC plug connectors.

[0044] The detection circuit of this scheme can be an existing amplification detection circuit, which will not be described here; the detection circuit can also be other detection circuits, as long as it can ensure that the current signal can be intuitively displayed; the following further describes the use of this device and the amplification detection circuit:

[0045] The third terminal 16 and all the first terminals 14 are connected to the BNC plug connector, and the BNC plug connector is connected to the amplification detection circuit, so that the current signal collected by the main ionization chamber and the secondary ionization chamber is transmitted to the amplification detection circuit; specifically, the signal collected by the secondary ionization chamber is fed back to the console after analog-to-digital conversion by the amplification detection circuit, and the symmetry and uniformity of the beta particle beam are monitored; the current signal collected by the main ionization chamber is converted into the absolute dose of the beta particle beam by the national standard software calculation formula of the amplification detection circuit. The radiation dose of the high-energy beta particle beam, as well as the symmetry and uniformity of the radiation, can be quickly determined by the amplification detection circuit. When the preset absolute dose is reached, the beta particle beam is cut off, thereby ensuring that the absolute dose of the beta particle beam received during the treatment of the patient is stable and reliable.

[0046] The following further explains how the secondary ionization chamber determines the symmetry and uniformity of the beta particle beam:

[0047] The areas of the first conductive layer 303 and the annular conductive layer 302 are equal, and the four annular conductive layers 302 are symmetrically arranged. Therefore, the currents collected by the first conductive layer 303 and the four annular conductive layers 302 should be equal or have a small difference in theory. Therefore, by using this principle, in actual measurement, the current size of the segment signal of the secondary ionization chamber can be used to determine whether the ray quality is evenly distributed. For example, when the five current sizes are equal or have a small difference, it indicates that the ray quality is evenly distributed; when the current sizes of the five segment signals differ greatly, it indicates that the ray quality is unevenly distributed. At this time, it is necessary to adjust the installation position of the accelerator and the β-particle beam detector to play a warning role.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A beta particle beam current measuring device, characterized in that: It comprises an anode plate (5), wherein a metal spacer ring (4), a secondary ionization plate (3) and a first insulating film (2) are stacked on one plate surface of the anode plate (5) to form a secondary ionization chamber, and a main ionization plate (6), a second insulating film and a main ionization plate pressure ring (7) are stacked on the other plate surface to form a main ionization chamber; A leveling filter device is provided on the main ionization plate pressure ring (7) via a plastic spacer ring (8), the leveling filter device comprising a leveling block pressure ring (9) superimposed on the plastic spacer ring (8), a third insulating film (10) and a fourth insulating film (12) with a leveling block (11) in the middle; The main ionization chamber, the secondary ionization chamber and the leveling filter device are fixed between the top cover (1) and the bottom plate (13); the top cover (1) is provided with a plurality of terminals plugged into the secondary ionization plate (3), the anode plate (5) and the main ionization plate (6); The secondary ionization plate (3), the primary ionization plate (6), the anode plate (5), the first insulating film (2), the second insulating film, the third insulating film (10) and the fourth insulating film (12) are all made of polyurethane; A first conductive layer (303) located in the middle and an annular conductive layer (302) of N 1 / N circular rings symmetrically arranged around the first conductive layer (303) are arranged on the front plate surface of the secondary ionization plate (3); the first conductive layer (303) and each annular conductive layer (302) have the same area.

2. The beta particle beam current measuring device according to claim 1, characterized in that: The metal spacer rings (4) are not in contact with the annular conductive layer (302); A secondary ionization plate (3) located outside the annular conductive layer (302) is provided with M first through holes (301) respectively matched with M first terminals (14); a first lead layer of the first conductive layer (303) and second lead layers of N annular conductive layers (302) are respectively connected to the M first through holes (301); there are gaps between the first conductive layer (303) and the annular conductive layer (302) and between adjacent annular conductive layers (302); wherein M=N+1; A second conductive layer is provided on the secondary plate surface of the secondary ionization plate (3).

3. The beta particle beam current measuring device according to claim 2, characterized in that: The two plate surfaces of the anode plate (5) are both provided with a first annular groove (502); the anode plate (5) located inside the first annular groove (502) is provided with a third conductive layer (501); the anode plate (5) located outside the first annular groove (502) is provided with two second through holes (503) and a third through hole (504); the two second through holes (503) are both connected to the third conductive layer (501) on one plate surface, and the two third through holes (504) are both connected to the third conductive layer (501) on the other plate surface; one of the second through holes (503) and one of the third through holes (504) are connected by a wire, and the other second through hole (503) and the other third through hole (504) are respectively plugged with a second terminal (15) connected to the positive electrode of the power supply.

4. The beta particle beam current measuring device according to claim 3, characterized in that: A second annular groove (603) is provided on the front plate surface of the main ionization plate (6), a fourth conductive layer (601) is provided on the main ionization plate located in the second annular groove (603), and a fourth through hole (602) cooperating with the third terminal (16) is provided on the main ionization plate (6) located outside the second annular groove (603); A fifth conductive layer is provided on the secondary plate surface of the main ionization plate (6).

5. The beta particle beam current measuring device according to claim 4, characterized in that: The second conductive layer and the fifth conductive layer are both connected to the negative electrode of the power supply.

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