An X-ray detector

Abstract

The present invention provides an X-ray detector, which includes an anode ceramic plate. A lead ring, a ceramic ring, a lead ring and a secondary ceramic plate are stacked on one side surface of the anode ceramic plate to form a secondary ionization chamber, and a lead ring, a ceramic ring, a lead ring and a main ceramic plate are stacked on the other side surface to form a main ionization chamber; gases are filled in the main ionization chamber and the secondary ionization chamber; both the main ionization chamber and the secondary ionization chamber are connected to a BNC plug connector.

Description

Technical Field

[0001] The present invention relates to the technical field of detectors, and particularly relates to an X-ray detector. Background Art

[0002] High-energy X-ray dose measurement devices are the main devices used in industries such as medical radiotherapy to measure the output dose of X-rays, used to measure the absorbed dose of X-rays of patients undergoing radiotherapy, and at the same time monitor the changes in the X-ray flatness and symmetry of the ray quality in the entire radiotherapy plane area.

[0003] Currently, the main problems existing in the devices for measuring high-energy X-ray doses are as follows: The devices for measuring high-energy X-ray doses can only be used for dose measurement and cannot be used to monitor the changes in ray quality (flatness and symmetry changes); such devices can only measure in a single channel and cannot measure simultaneously in two channels. Summary of the Invention

[0004] In view of the above deficiencies in the prior art, the present invention provides an X-ray detector, and its purpose is to solve the problem that the high-energy X-ray dose measurement device can only measure the ray dose and cannot monitor the flatness and symmetry of the rays.

[0005] In order to achieve the above invention purpose, the present invention adopts the following technical solutions:

[0006] Provide an X-ray detector, which includes an anode ceramic plate. A secondary ionization chamber is formed by a lead ring, a ceramic ring, a lead ring, and a secondary ceramic plate laminated on one side plate surface of the anode ceramic plate, and a main ionization chamber is formed by a lead ring, a ceramic ring, a lead ring, and a main ceramic plate laminated on the other side plate surface; gases are filled in the main ionization chamber and the secondary ionization chamber; both the main ionization chamber and the secondary ionization chamber are connected to a BNC plug connector.

[0007] Further, a cross groove is provided in the middle of the positive plate surface of the secondary ceramic plate, and linear grooves evenly dividing each quadrant are provided in the four quadrants of the cross groove;

[0008] A first conductive layer is provided in the cross groove, a second conductive layer is provided in each linear groove, a third conductive layer is provided on the positive plate surface of the secondary ceramic plate where the first conductive layer and the second conductive layer are not provided, and after the secondary ceramic plate is installed on the lead ring, both the first conductive layer and the second conductive layer are located inside the inner circle of the lead ring; there is a gap between any two of the first conductive layer, the second conductive layer, and the third conductive layer;

[0009] A first connection point and four second connection points are provided on the negative plate surface of the secondary ceramic plate, the first conductive layer is connected to the first connection point, and the four second conductive layers are respectively connected to the four second connection points.

[0010] Further, a first annular groove and four arc grooves are provided on the negative plate surface of the secondary ceramic plate; four first through holes are provided on the secondary ceramic plate between the four ends of the cross groove and the first annular groove, and the first conductive layer extends into the first annular groove through the first through holes and is connected to the first wiring point;

[0011] Second through holes are provided on the secondary ceramic plate between the ends of the straight groove and the arc grooves, and the four second conductive layers respectively extend into the four arc grooves through the four second through holes and are respectively connected to the four second wiring points.

[0012] Further, one end of the straight groove close to the center of the cross groove is set as a quarter circle ring. The quarter circles are in four sides, symmetric with each other and equal in area. The purpose is to capture the largest ray mass area per unit area.

[0013] Further, a second annular groove is provided on the positive plate surface of the main ceramic plate, a fourth conductive layer is provided in the second annular groove, a fifth conductive layer is provided on the positive plate surface of the main ceramic plate outside the second annular groove. After the main ceramic plate is installed on the lead ring, the fourth conductive layer is located inside the inner ring of the lead ring;

[0014] Third through holes communicating with the second annular groove are provided on the main ceramic plate, and a third wiring point is provided on the negative plate surface of the main ceramic plate. The third wiring point is connected to the fourth conductive layer through the third through hole.

[0015] Further, sixth conductive layers are provided on both plate surfaces of the anode ceramic plate.

[0016] Further, the materials of the first conductive layer, the second conductive layer, the third conductive layer, the fourth conductive layer, the fifth conductive layer and the sixth conductive layer are silver paste or nickel.

[0017] Further, the lead rings close to the anode ceramic plate are all connected to the positive pole of the power supply, and the lead rings close to the main ceramic plate and the secondary ceramic plate are all connected to the negative pole of the power supply.

[0018] Further, the gas is dry air or nitrogen. Since nitrogen has the characteristics of low average ionization energy (21.9 eV), moderate atomic number (A is 7), and being insensitive to temperature, etc., nitrogen is used as the filling medium of the ionization chamber. The first purpose is to ionize gas molecules under the bombardment of rays to form positive and negative particle pairs, and form an electric current under the action of an electric field. The second purpose is that the density of gas molecules maintains a good low level of the intrinsic energy resolution under a standard atmospheric pressure. When its density is greater than 1.5 atmospheric pressures, the intrinsic energy resolution becomes poor. This is because when the gas density is too large, it will cause the recombination of the internally ionized positive and negative ions, thus deteriorating the energy resolution. Therefore, nitrogen under a standard atmospheric pressure is used; the same applies to dry air.

[0019] Furthermore, a wiring portion is provided on the lead ring, and the included angle between the wiring portions of adjacent lead rings is 10°-20°. The purpose is to facilitate the wiring, silicone potting, and measurement, and prevent short circuits caused by too close distances.

[0020] The beneficial effects of the present invention are as follows: In this solution, the device uses a ceramic material as the conductive base material, which has good insulation and stable material properties. It only needs to be sintered in dry air under normal atmospheric pressure, avoiding the problem of using an inert gas filling method for insulation isolation in existing ionization chambers. The secondary ionization chamber judges the flatness and symmetry of the ray quality by the magnitude of the collected current under the action of a constant electric field; since the areas of the four linear grooves are equal and the cross groove is equally divided, the flatness and symmetry of the ray quality are judged by the magnitudes of the currents in the cross groove and the four linear grooves; the area of the fourth conductive layer of the main ionization chamber is relatively large, and the magnitude of the current passing through the fourth conductive layer is convenient for measuring the absolute dose of high-energy X-rays.

[0021] In addition to the technical problems solved by the present invention, the technical features constituting the technical solution, and the beneficial effects brought by these technical features described above, the other technical problems that the present invention can solve, the other technical features included in the technical solution, and the beneficial effects brought by these technical features will be further described in detail in the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0023] Figure 1 is a schematic structural diagram of an X-ray detector in the present invention.

[0024] Figure 2 is a schematic diagram of the positive plate surface of the secondary ceramic plate.

[0025] Figure 3 is another schematic diagram of the positive plate surface of the secondary ceramic plate.

[0026] Figure 4 is a schematic diagram of the negative plate surface of the secondary ceramic plate.

[0027] Figure 5 is a schematic diagram of the positive plate surface of the main ceramic plate.

[0028] Figure 6 is another schematic diagram of the negative plate surface of the main ceramic plate.

[0029] Among them: 1. Main ceramic plate; 101. Fifth conductive layer; 102. Second annular groove; 103. Fourth conductive layer; 104. Third through hole; 2. Lead ring; 3. Ceramic ring; 4. Anode ceramic plate; 5. Secondary ceramic plate; 501. First conductive layer; 502. Second conductive layer; 503. Third conductive layer; 504. Gap; 505. First annular groove; 506. Arc-shaped groove; 507. Cross-shaped groove; 508. Linear groove; 509. First through hole; 510. Second through hole. Specific embodiments

[0030] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] Please refer to Figures 1-6 , the present invention provides an X-ray detector, which includes an anode ceramic plate 4. A secondary ionization chamber is formed by laminating a lead ring 2, a ceramic ring 3, a lead ring 2, and a secondary ceramic plate 5 on one side plate surface of the anode ceramic plate 4, and a main ionization chamber is formed by laminating a lead ring 2, a ceramic ring 3, a lead ring 2, and a main ceramic plate 1 on the other side plate surface; the main ionization chamber and the secondary ionization chamber are filled with gas; both the main ionization chamber and the secondary ionization chamber are connected to a BNC plug connector. The provided ceramic ring 3 is used to separate two adjacent lead rings 2. The lead ring 2 plays an electric field constraint role and is also used to connect the power supply to the main ceramic plate 1, the secondary ceramic plate 5, and the anode ceramic plate 4.

[0032] In the middle of the positive plate surface of the secondary ceramic plate 5, a cross groove 507 is provided, and linear grooves 508 that evenly divide each quadrant are provided in the four quadrants of the cross groove 507; a first conductive layer 501 is provided in the cross groove 507, and a second conductive layer 502 is provided in each linear groove 508. A third conductive layer 503 is provided on the positive plate surface of the secondary ceramic plate 5 where the first conductive layer 501 and the second conductive layer 502 are not provided. After the secondary ceramic plate 5 is installed on the lead ring 2, both the first conductive layer 501 and the second conductive layer 502 are located inside the inner ring of the lead ring 2; there is a gap 504 between any two of the first conductive layer 501, the second conductive layer 502, and the third conductive layer 503. The provided gap 504 can avoid any interference between the first conductive layer 501, the second conductive layer 502, and the third conductive layer 503, ensure the uniformity of photons in the secondary ionization chamber, and make the lead ring 2 only contact and connect with the third conductive layer 503. On the negative plate surface of the secondary ceramic plate 5, a first wiring point and four second wiring points are provided. The first conductive layer 501 is connected to the first wiring point, and the four second conductive layers 502 are respectively connected to the four second wiring points. Both the first wiring point and the second wiring point are connected to the BNC plug connector.

[0033] Preferably, the axes of all the first through holes 509 and the second through holes 510 are on the same circle. The positive plate surface of the secondary ceramic plate 5 is equally divided by the provided cross groove 507 and the four linear grooves 508, which can ensure the formation of a constant electric field on the anode ceramic plate 4. At the same time, the cross groove 507 and the four linear grooves 508 can judge the uniformity of photons. It should be noted that the side of the secondary ceramic plate 5 and the main ceramic plate 1 close to the lead ring 2 is the positive plate surface, and the side far from the lead ring 2 is the negative plate surface.

[0034] On the negative plate surface of the secondary ceramic plate 5, a first ring groove 505 and four arc grooves 506 are provided; four first through holes 509 are provided on the secondary ceramic plate 5 between the four ends of the cross groove 507 and the first ring groove 505. After the first conductive layer 501 extends into the first ring groove 505 through the first through holes 509, it is connected to the first wiring point; second through holes 510 are provided on the secondary ceramic plate 5 between the ends of the linear grooves 508 and the arc grooves 506. The four second conductive layers 502 respectively extend into the four arc grooves 506 through the four second through holes 510 and are respectively connected to the four second wiring points. One end of the linear groove 508 close to the center of the cross groove 507 is set as a quarter of a ring, which increases the area of the linear groove 508, makes the area of the first conductive layer 501 larger, and collects more current.

[0035] On the positive plate surface of the main ceramic plate 1, a second annular groove 102 is provided, and the provided second annular groove 102 serves a dividing function. A fourth conductive layer 103 is provided in the second annular groove 102. On the positive plate surface of the main ceramic plate 1, a fifth conductive layer 101 is provided outside the second annular groove 102. After the main ceramic plate 1 is installed on the lead ring 2, the fourth conductive layer 103 is located inside the inner ring of the lead ring 2. A third through hole 104 communicating with the second annular groove 102 is provided on the main ceramic plate 1. A third wiring point is provided on the negative plate surface of the main ceramic plate 1, and the third wiring point is connected to the fourth conductive layer 103 through the third through hole 104. In this way, the ionized electrons can move onto the fourth conductive layer 103 and be transmitted to the third wiring point, and the third wiring point is connected to the BNC plug connector. The provided fifth conductive layer 101 can form a constant electric field with the anode ceramic plate 4.

[0036] Sixth conductive layers are provided on both plate surfaces of the anode ceramic plate 4. The materials of the first conductive layer 501, the second conductive layer 502, the third conductive layer 503, the fourth conductive layer 103, the fifth conductive layer 101, and the sixth conductive layer are silver paste or nickel. The provided silver paste or nickel has good electrical conductivity, is convenient for electroplating onto the ceramic plate, and does not damage the ceramic plate substrate.

[0037] The lead rings 2 close to the anode ceramic plate 4 are all connected to the positive pole of the power supply, and the lead rings 2 close to the main ceramic plate 1 and the secondary ceramic plate 5 are all connected to the negative pole of the power supply. The gas is dry air or nitrogen. Compared with the inert gas selected by the detector in the background technology, selecting dry air or nitrogen saves costs. The lead ring 2 is provided with a wiring portion, and the included angle between the wiring portions of adjacent lead rings 2 is 10° - 20°; preferably, the included angle between the wiring portions of adjacent lead rings 2 is 10°, which is convenient for the connection of the power supply lines and can avoid interference between the power supply lines. Among them, the power supply is 600VDC.

[0038] Since high-energy X-rays (photons) cannot directly cause ionization, they lose energy through photoelectric absorption, Compton scattering, and electron pair generation to produce secondary electrons, and ionize the air based on the principle of generating secondary electrons; the main cause of the actual ionization of the air is still the secondary electrons. Photons or primary electrons first generate secondary electrons in the interaction with the gas. As an ionization chamber, the secondary electrons entering the air cavity of the ionization chamber are mainly generated in the wall of the ionization chamber.

[0039] Since the density of the wall material is much greater than that of air and more electrons are generated, the secondary electrons entering the air-sensitive volume of the ionization chamber increase as the wall thickness increases. When the wall thickness of the ionization chamber increases to a certain extent, the blocking effect of the ionization chamber wall on secondary electrons becomes obvious and ultimately makes the number of secondary electrons entering the sensitive volume equal to the number of secondary electrons escaping from the sensitive volume. This state is called electron equilibrium or electron buildup. Therefore, the thicknesses of the secondary ceramic plate 5, the ceramic ring 3, the anode ceramic plate 4, and the main ceramic plate 1 are all designed to be 1.6 mm. The material of the lead ring 2 is oxygen-free copper and its thickness is 0.1 mm. The lead ring is arranged as evenly as possible on the equipotential surface of the electric field.

[0040] The high-energy X-rays emitted by the accelerator enter the secondary ionization chamber from the negative plate surface of the secondary ceramic plate and generate excited electrons with the conductive layer of the secondary ceramic plate 5. Under the constant current DC power supply, the main ceramic plate 1 or the secondary ceramic plate 5 and the anode ceramic plate 4 generate a constant electric field in the main ionization chamber or the secondary ionization chamber. The ionized positive and negative ion pairs move directionally under the action of the constant electric field to form a current (specifically, the positive ions in the secondary ionization chamber move towards the anode ceramic plate 4, and the negative ions move towards the secondary ceramic plate 5; the positive ions in the main ionization chamber move towards the anode ceramic plate 4, and the negative ions move towards the main ceramic plate 1), and are transmitted to the BNC plug connector through the first connection point, the second connection point, and the third connection point. The BNC plug connector transmits the current signals collected by the main ionization chamber and the secondary ionization chamber to the next-stage signal amplification circuit through the lead wire. The ray dose, symmetry, and uniformity of the high-energy X-rays can be quickly judged through the signal amplification circuit.

[0041] Specifically, the areas of the first conductive layer and the second conductive layer are equal. Since the areas of the linear grooves 508 are equal and symmetrically arranged, it is stipulated that the current output by the cross groove 507 is the segment 0 signal, and the currents output by the four linear grooves 508 in the counterclockwise direction are the segment 1 signal, the segment 2 signal, the segment 3 signal, and the segment 4 signal respectively; that is, the magnitudes of the currents collected by the segment 0 signal, the segment 1 signal, the segment 2 signal, the segment 3 signal, and the segment 4 signal should be equal or differ very little in theory. Therefore, using this principle, during actual measurement, the uniformity of the ray quality can be judged by the magnitudes of the currents of the segment signals of the secondary ionization chamber. For example, when the magnitudes of the currents of the five segment signals are equal or differ very little, it indicates that the ray quality is evenly distributed; when the magnitudes of the currents of the five segment signals differ greatly, it indicates that the ray quality is unevenly distributed. At this time, the installation positions of the accelerator and the X-ray detector need to be adjusted to play a warning role.

[0042] The following is an example to illustrate the specific usage of the X-ray detector and the signal amplification circuit:

[0043] The BNC plug connector of the X-ray detector is connected to the amplifier of the signal amplification circuit. After the current signals collected by the main ionization chamber and the secondary ionization chamber are transmitted to the amplifier through the BNC plug connector and amplified, they are then transmitted to the console through V / F and F / D conversions. The gain of the amplifier is controlled by the D / F conversion of the console, thereby changing the magnitude of the current signal amplified by the amplifier. By judging the magnitude of the current signal after gain, it can be determined whether the absolute value of the radiation dose meets the GB regulations.

[0044] 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 them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and 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. An X-ray detector, characterized in that, It includes an anode ceramic plate (4). A lead ring (2), a ceramic ring (3), a lead ring (2) and a secondary ceramic plate (5) stacked on one side plate surface of the anode ceramic plate (4) form a secondary ionization chamber, and a lead ring (2), a ceramic ring (3), a lead ring (2) and a main ceramic plate (1) stacked on the other side plate surface form a main ionization chamber; gases are filled in the main ionization chamber and the secondary ionization chamber; both the main ionization chamber and the secondary ionization chamber are connected to a BNC plug connector; A cross groove (507) is provided in the middle of the positive plate surface of the secondary ceramic plate (5), and linear grooves (508) that evenly divide each quadrant are provided in the four quadrants of the cross groove (507); A first conductive layer (501) is provided in the cross groove (507), a second conductive layer (502) is provided in each linear groove (508), and a third conductive layer (503) is provided on the positive plate surface of the secondary ceramic plate (5) where the first conductive layer (501) and the second conductive layer (502) are not provided. After the secondary ceramic plate (5) is installed on the lead ring (2), both the first conductive layer (501) and the second conductive layer (502) are located in the inner circle of the lead ring (2); there is a gap (504) between any two of the first conductive layer (501), the second conductive layer (502) and the third conductive layer (503); A first connection point and four second connection points are provided on the negative plate surface of the secondary ceramic plate (5), the first conductive layer (501) is connected to the first connection point, and the four second conductive layers (502) are respectively connected to the four second connection points.

2. The X-ray detector according to claim 1, characterized in that, A first annular groove (505) and four arc grooves (506) are provided on the negative plate surface of the secondary ceramic plate (5); four first through holes (509) are provided on the secondary ceramic plate (5) between the four ends of the cross groove (507) and the first annular groove (505), and the first conductive layer (501) extends into the first annular groove (505) through the first through holes (509) and is connected to the first connection point; Second through holes (510) are provided on the secondary ceramic plate (5) between the ends of the linear grooves (508) and the arc grooves (506), and the four second conductive layers (502) respectively extend into the four arc grooves (506) through the four second through holes (510) and are respectively connected to the four second connection points.

3. The X-ray detector according to claim 1, characterized in that, One end of the linear groove (508) close to the center of the cross groove (507) is set as a quarter of a circular ring.

4. The X-ray detector according to claim 3, characterized in that, A second annular groove (102) is provided on the positive plate surface of the main ceramic plate (1), a fourth conductive layer (103) is provided in the second annular groove (102), a fifth conductive layer (101) is provided on the positive plate surface of the main ceramic plate (1) outside the second annular groove (102), and after the main ceramic plate (1) is installed on the lead ring (2), the fourth conductive layer (103) is located in the inner circle of the lead ring (2); A third through hole (104) communicating with the second annular groove (102) is provided on the main ceramic plate (1). A third wiring point is provided on the negative plate surface of the main ceramic plate (1), and the third wiring point is connected to the fourth conductive layer (103) through the third through hole (104).

5. The X-ray detector according to claim 4, characterized in that, Sixth conductive layers are provided on both plate surfaces of the anode ceramic plate (4).

6. The X-ray detector according to claim 5, characterized in that, The materials of the first conductive layer (501), the second conductive layer (502), the third conductive layer (503), the fourth conductive layer (103), the fifth conductive layer (101), and the sixth conductive layer are silver paste or nickel.

7. The X-ray detector according to claim 1, characterized in that, The lead rings (2) close to the anode ceramic plate (4) are all connected to the positive pole of the power supply, and the lead rings (2) close to the main ceramic plate (1) and the secondary ceramic plate (5) are all connected to the negative pole of the power supply.

8. The X-ray detector according to claim 1, characterized in that, The gas is dry air or nitrogen.

9. The X-ray detector according to claim 1, characterized in that, A wiring portion is provided on the lead ring (2), and the included angle between the wiring portions of adjacent lead rings (2) is 10°-20°.

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