Scanning magnet, scanning box and linear accelerator

Abstract

The utility model discloses a scanning magnet, a scanning box and a linear accelerator, the linear accelerator comprises the scanning box, the top of the scanning box is provided with a scanning magnet bracket, the scanning magnet is arranged above the scanning magnet bracket, the scanning magnet comprises two iron cores and two coils, each iron core comprises a middle protrusion, a connecting piece and two side protrusions, and the two coils are arranged on the middle protrusion. The two side protrusions are arranged at the two ends of the connecting piece respectively, and the middle protrusion is arranged between the side protrusions. When the scanning magnet is installed above the scanning magnet bracket, the two coils are clamped on the two sides of the scanning box through the two iron cores, the scanning magnet is fixed to the scanning magnet bracket through a fixing support, a middle protrusion penetrates through middle holes of the coils and then is connected with the scanning box, and side protrusions of the two iron cores are connected with each other. The top side face and / or the bottom side face of the middle protrusion are / is provided with a fillet structure. The scanning box can change the distribution of a deflection magnetic field, improve the distribution uniformity of electrons, prolong the service life of the scanning box and improve the use efficiency of the electrons.

Description

Technical Field

[0001] The utility model relates to a scanning magnet, a scanning box and a linear accelerator. Background Art

[0002] A linear accelerator usually refers to an accelerator that uses a high-frequency electromagnetic field to accelerate particles, and the trajectory of the accelerated particles is a straight line. A high-frequency linear accelerator (HLA) is a device that accelerates charged particles using a high-frequency electric field distributed along a straight track.

[0003] The accelerating cavity in a high-frequency linear accelerator usually uses radio frequency acceleration technology, that is, using a high-frequency electric field to accelerate charged particles. By introducing a high-frequency electric field in the accelerating cavity, the particles can obtain higher energy and speed. High-frequency linear accelerators usually have higher acceleration capabilities and efficiency, so they have advantages in generating high-energy particle beams.

[0004] In the medical field, high-frequency linear accelerators are widely used in radiotherapy to treat cancer and tumors. By generating high-energy electron or photon beams, this accelerator can precisely target tumor cells and deliver high-energy particle beams into the patient's body to destroy malignant cells.

[0005] In the field of industrial production and processing, industrial linear accelerators can play a role in disinfecting and sterilizing products.

[0006] Accelerator irradiation processing equipment uses the generated electron beam to irradiate and sterilize the goods. When the electron beam hits the surface of the goods and the conveyor line, some electrons are absorbed and some are scattered, causing the rays to disperse in all directions. The greater the energy of the rays, the stronger the penetrability.

[0007] In existing linear accelerators, moving electrons will be deflected in the magnetic field. The greater the speed (i.e., energy), the smaller the deflection angle θ, and the smaller the energy of the electron, the larger the deflection angle. When the current in the coil of the magnet is reversed, the magnetic field immediately changes direction, and the electrons will be deflected to the other side. When a periodic positive and negative triangular wave current is provided to the magnet, multiple electron bunches will randomly fall in a strip area. However, due to the unsatisfactory triangular wave shape of the scanning current and other reasons, the distribution probability of electrons at each point in the actual distribution band is not the same, and extreme value fluctuations occur, which can easily cause the dose of the irradiated goods to exceed the standard or be damaged, and even affect the safe operation of the equipment. Utility Model Content

[0008] The technical problem to be solved by the present utility model is to overcome the defect that in the prior art, the distribution probability of electrons in the existing linear accelerator is not the same at each point, resulting in extreme value fluctuations, which are likely to cause equipment damage. The present utility model provides a scanning magnet, a scanning box and a linear accelerator that can change the distribution of the deflection magnetic field, improve the distribution uniformity of electrons, and can increase the service life of the scanning box and the electron utilization efficiency.

[0009] The present utility model solves the above technical problem through the following technical solutions:

[0010] A scanning magnet for a linear accelerator, characterized in that the linear accelerator includes a scanning box, a scanning magnet bracket is provided at the top of the scanning box, the scanning magnet is provided above the scanning magnet bracket, and the scanning magnet includes two iron cores and two coils.

[0011] Each iron core includes a middle protrusion, a connecting member and two side protrusions. The two side protrusions are respectively provided at both ends of the connecting member, and the middle protrusion is provided between the side protrusions.

[0012] When the scanning magnet is installed above the scanning magnet bracket, the two iron cores clamp the two coils on both sides of the scanning box, and a fixing bracket is used to fix the scanning magnet on the scanning magnet bracket. The middle protrusion passes through the middle hole of the coil and then is connected to the scanning box, and the side protrusions of the two iron cores are connected to each other.

[0013] A fillet structure is provided on the top side and / or the bottom side of the top of the middle protrusion.

[0014] Preferably, each iron core includes a plurality of silicon steel sheets stacked together. The top and / or the bottom of the iron core includes a preset number of adjustable silicon steel sheets. The length of the middle protrusion of the adjustable silicon steel sheets at the top or the bottom increases or decreases in one direction, and the middle protrusion is formed after the silicon steel sheets are stacked.

[0015] Preferably, the silicon steel sheets have the same thickness, and the thickness of the silicon steel sheets is greater than 0.1 mm and less than 2 mm.

[0016] Preferably, the fixing bracket includes a mounting plate and fixing bolts. After the two iron cores clamp the two coils on both sides of the scanning box, the two iron cores are clamped and fixed by using the mounting plate and the fixing bolts.

[0017] Preferably, the fillet radius of the fillet structure is greater than 15 mm and less than 35 mm.

[0018] Preferably, the sum of the two side protrusions is equal to the sum of the two middle protrusions and the thickness of the scanning box.

[0019] Preferably, the scanning box is arranged below the accelerating tube. The scanning box includes two front panels and two rear panels in the shape of isosceles triangles. The two sides of the front panel and the rear panel are connected by side panels. A scanning box flange is provided at the bottom of the scanning box.

[0020] Preferably, a water-cooling box is attached to the outer side of each side panel correspondingly. The water-cooling box is located between the scanning magnet bracket and the scanning box flange. A water-cooling box water inlet is provided at one end of each water-cooling box, and a water-cooling box water outlet is provided at the other end. The two water-cooling box water inlets are connected to the pipeline water outlet of a target water-cooling pipeline through a first three-way joint, and the two water-cooling box water outlets are connected to the pipeline water return port of the target water-cooling pipeline through a second three-way joint. The water-cooling system includes the target water-cooling pipeline.

[0021] The present invention also provides a scanning box for a linear accelerator, characterized in that the scanning magnet as described above is installed on the top of the scanning box.

[0022] The present invention also provides a linear accelerator, characterized in that the linear accelerator system includes the scanning box for a linear accelerator as described above.

[0023] On the basis of conforming to the common knowledge in the art, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0024] The positive and progressive effects of the present invention are as follows:

[0025] The present invention can change the deflection magnetic field distribution, improve the distribution uniformity of electrons, and improve the electron utilization efficiency and the service life of the scanning box. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of the electron distribution structure of the scanning magnet in the prior art.

[0027] Figure 2 It is a schematic diagram of the structure of the scanning magnet in the prior art.

[0028] Figure 3 It is a schematic diagram of the structure of the scanning magnet of Embodiment 1 of the present invention.

[0029] Figure 4 It is a schematic diagram of the electron distribution structure of the scanning magnet of Embodiment 1 of the present invention.

[0030] Figure 5 It is an exploded view of the scanning magnet of Embodiment 1 of the present invention.

[0031] Figure 6 It is a schematic diagram of the structure after the silicon steel sheets of Embodiment 1 of the present invention are stacked.

[0032] Figure 7 Schematic structural diagram of the scanning magnet according to Embodiment 1 of the present utility model.

[0033] Figure 8 Schematic structural diagram of the scanning box according to Embodiment 1 of the present utility model.

[0034] Figure 9 Top view structural schematic diagram of the iron core according to Embodiment 1 of the present utility model. Detailed implementation manners

[0035] The present utility model will be further described below by way of embodiments, but the present utility model is not limited to the scope of the described embodiments. Embodiment

[0036] In this embodiment, the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0037] Refer to Figures 3 to 9 , this embodiment provides an industrial linear accelerator.

[0038] The industrial linear accelerator includes a scanning box 100 and a scanning magnet 101.

[0039] The scanning box 100 is disposed below the accelerating tube. The scanning box includes two isosceles triangular front panels and rear panels.

[0040] Both sides of the front panel and the rear panel are connected by side panels.

[0041] The top of the scanning box is provided with a scanning magnet bracket 102, and the bottom of the scanning box is provided with a scanning box flange 103.

[0042] The scanning magnet is disposed above the scanning magnet bracket. The scanning magnet 101 includes two iron cores 1011 and two coils 1012.

[0043] The iron core includes a middle protrusion 1013, a connecting member 1014, and two side protrusions 1015. The two side protrusions 1015 are respectively disposed at both ends of the connecting member 1014, and the middle protrusion 1013 is disposed between the side protrusions 1015.

[0044] When the scanning magnet is installed above the scanning magnet bracket, the two iron cores clamp the two coils on both sides of the scanning box.

[0045] The scanning magnet is fixed to the scanning magnet bracket by a fixing bracket, the middle protrusion passes through the middle hole of the coil and is connected to the scanning box (the middle protrusion fits with the scanning box), and the side protrusions of the two iron cores are connected to each other (fitted);

[0046] A rounded structure 104 is provided on the bottom side of the middle protrusion.

[0047] Moving electrons will be deflected in a magnetic field. The greater the speed (i.e., energy), the smaller the deflection angle θ. The smaller the energy of the electron, the larger the deflection angle. When the current in the coil of the magnet is reversed, the magnetic field changes direction and the electrons are deflected to the other side. When a periodic positive and negative triangular wave current is provided to the magnet, multiple electron bunches will randomly fall in a strip area.

[0048] However, due to the unsatisfactory triangular wave shape of the scanning current, the distribution probability of electrons at various points in the distribution band is not the same, and often appears Figure 1 distributed:

[0049] The scan width position 0cm is the point corresponding to the center of the scanning box, and the negative value is the point area on the left side of the scanning box. The irradiation dose can be regarded as the number of electrons, then Figure 1 It reflects the distribution probability of electrons in the landing point distribution band. The distribution is relatively flat in the middle plateau area, and has two "peaks" on the edges on both sides, that is, there is a large drop between the highest point and the lowest point in the effective distribution range (between -40 and +40). The extreme value fluctuation cannot exceed 5%, otherwise it does not meet the irradiation process requirements ( Figure 1 shown exceeded).

[0050] The solution provided in this embodiment changes the deflection magnetic field distribution by changing the shape of the scanning magnet, thereby further improving the distribution uniformity of electrons.

[0051] The core of a magnet is generally a regular rectangle, and the magnetic field it generates is a uniformly distributed area, see Figure 2 .

[0052] Because moving electrons will be deflected in a magnetic field, and the stronger the magnetic field, the smaller the deflection radius (R) and the larger the deflection angle (θ1). When the scanning current reaches the maximum value of the waveform, the electron deflection angle also reaches the maximum value.

[0053] Regarding the distribution of existing electrons ( Figure 1 ), it can be seen that the number of electrons corresponding to the maximum angle θ1 is significantly greater than the number of electrons in the central plateau area.

[0054] The problem is transformed into how to reduce the number of electrons at the "peaks" on both sides and further disperse them into the central plateau area.

[0055] In this embodiment, the conventional rectangular regular iron core is changed to a rounded iron core ( Figure 3 as shown), so as to change the path length that electrons pass through when passing through the magnetic field, enable the electrons to be emitted from the magnetic field in advance, thereby reducing the action time of the electrons under the magnetic field and corresponding to a smaller deflection angle θ2;

[0056] Different rounded corners of the iron core will correspond to different magnetic field shapes, and further reduce the number of electrons at the θ1 angle. The reduced electrons will be dispersed into the θ2 angle range.

[0057] Thus, by changing the rounded corner size of the magnet, the Figure 1 distribution probability of electrons at each position can be changed, so that the peaks are pulled down as much as possible, reducing the range difference between the peaks and the plateau area, and achieving improved uniformity.

[0058] In this embodiment, the distribution probability of electrons at each point is more average, showing a Figure 4 distribution. Therefore, this embodiment can change the deflection magnetic field distribution, improve the distribution uniformity of electrons, and increase the service life of the scanning box and the electron usage efficiency.

[0059] The iron core 1011 includes a plurality of silicon steel sheets 1016 stacked together. The bottom of the iron core 1011 includes a preset number of adjustable silicon steel sheets 1016. The length of the middle convex part of the adjustable silicon steel sheets 1016 at the bottom increases or decreases in one direction (in this embodiment, it increases upward). After the silicon steel sheets are stacked, the middle convex parts form the middle convex.

[0060] In each silicon steel sheet, the corresponding part of the middle convex, the corresponding part of the connecting piece, and the corresponding part of the side convex are all integrally formed structures.

[0061] The rounded corners of the iron core can be located at the lower part of the iron core, or at the upper part of the iron core, or a combination of both.

[0062] The silicon steel sheets have the same thickness, and the thickness of the silicon steel sheets is greater than 0.1 mm and less than 2 mm. Preferably, the thickness of this embodiment is 1 mm.

[0063] The fixing bracket includes a mounting piece 105 and fixing bolts 106. After the two iron cores 1011 clamp the two coils 1012 on both sides of the scanning box, the two iron cores are clamped and fixed by using the mounting piece 105 and the fixing bolts 106.

[0064] The rounded corner radius of the rounded corner structure is greater than 15 mm and less than 35 mm. Preferably, the rounded corner radius of this embodiment is 20 mm.

[0065] The sum of the two side protrusions is equal to the sum of the two middle protrusions and the thickness of the scanning box.

[0066] The scanning box is arranged below the acceleration tube. The scanning box includes two front panels and two back panels in the shape of isosceles triangles. The two sides of the front panel and the back panel are connected by side panels. A scanning box flange is provided at the bottom of the scanning box.

[0067] A water-cooling box is correspondingly attached to the outside of each side panel. The water-cooling box is located between the scanning magnet bracket and the scanning box flange. A water-cooling box water inlet is provided at one end of each water-cooling box, and a water-cooling box water outlet is provided at the other end. The two water-cooling box water inlets are connected to the pipeline water outlet of a target water-cooling pipeline through a first three-way joint, and the two water-cooling box water outlets are connected to the pipeline water return port of the target water-cooling pipeline through a second three-way joint. The water-cooling system includes the target water-cooling pipeline.

[0068] Although the specific implementation manners of the present invention have been described above, those skilled in the art should understand that these are only examples. The protection scope of the present invention is defined by the appended claims. Without departing from the principle and essence of the present invention, those skilled in the art can make various changes or modifications to these implementation manners, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A scanning magnet for a linear accelerator, characterized in that, The linear accelerator includes a scanning box, a scanning magnet bracket is provided at the top of the scanning box, the scanning magnet is provided above the scanning magnet bracket, and the scanning magnet includes two iron cores and two coils. The iron core includes a middle protrusion, a connecting piece, and two side protrusions. The two side protrusions are respectively provided at both ends of the connecting piece, and the middle protrusion is provided between the side protrusions. When the scanning magnet is installed above the scanning magnet bracket, the two iron cores clamp the two coils on both sides of the scanning box. A fixing bracket is used to fix the scanning magnet to the scanning magnet bracket. The middle protrusion passes through the middle hole of the coil and then is connected to the scanning box, and the side protrusions of the two iron cores are connected to each other. A fillet structure is provided on the top side and / or bottom side of the middle protrusion.

2. The scanning magnet for a linear accelerator according to claim 1, characterized in that, The iron core includes a plurality of silicon steel sheets stacked together. The top and / or bottom of the iron core includes a preset number of adjustable silicon steel sheets. The length of the middle protrusion of the adjustable silicon steel sheets at the top or bottom increases or decreases in one direction. After the silicon steel sheets are stacked, the middle protrusions form the middle protrusion.

3. The scanning magnet for a linear accelerator according to claim 2, wherein The silicon steel sheets have the same thickness, and the thickness of the silicon steel sheets is greater than 0.1 mm and less than 2 mm.

4. The scanning magnet for a linear accelerator according to claim 1, characterized in that, The fixing bracket includes a mounting plate and fixing bolts. After the two iron cores clamp the two coils on both sides of the scanning box, the two iron cores are clamped and fixed by the mounting plate and the fixing bolts.

5. The scanning magnet for a linear accelerator according to claim 1, characterized in that, The fillet radius of the fillet structure is greater than 15 mm and less than 35 mm.

6. The scanning magnet for a linear accelerator according to claim 1, characterized in that, The sum of the two side protrusions is equal to the sum of the two middle protrusions and the thickness of the scanning box.

7. The scanning magnet for a linear accelerator according to claim 1, wherein The scanning box is provided below the accelerating tube. The scanning box includes two front panels and two back panels in the shape of isosceles triangles. The two sides of the front panel and the back panel are connected by side panels. A scanning box flange is provided at the bottom of the scanning box.

8. The scanning magnet for a linear accelerator according to claim 7, wherein, A water-cooling box is correspondingly attached to the outside of each side panel. The water-cooling box is located between the scanning magnet bracket and the scanning box flange. A water-cooling box water inlet is provided at one end of each water-cooling box, and a water-cooling box water outlet is provided at the other end. The two water-cooling box water inlets are connected to the pipeline water outlet of a target water-cooling pipeline through a first three-way joint, and the two water-cooling box water outlets are connected to the pipeline water return port of the target water-cooling pipeline through a second three-way joint. The water-cooling system includes the target water-cooling pipeline.

9. A scanning box for a linear accelerator, characterized in that, The scanning magnet as described in any one of claims 1 to 8 is installed on the top of the scanning box.

10. A linear accelerator, characterized in that, The linear accelerator includes a scanning box for a linear accelerator as described in claim 9.

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