External collimator and control method for nondestructive testing accelerator

Abstract

The present disclosure provides an external collimator and control method for a nondestructive testing accelerator, the external collimator comprising a mounting frame; a lead screw connected to the mounting frame; a driving device for driving the lead screw to rotate; a collimation assembly connected to the lead screw, the collimation assembly can be driven by the lead screw to adjust the irradiation angle; and a bearing assembly arranged between the lead screw and the mounting frame for supporting the rotation of the lead screw, wherein the bearing assembly comprises: a bearing seat connected to the mounting seat, a middle hole penetrating the bearing seat and a positioning hole extending radially along the middle hole; a bearing arranged in the middle hole for cooperating with the lead screw to rotate; a positioning sleeve embedded in the middle hole and abutting against the bearing; a fixing member penetrating the positioning hole and connected to the positioning sleeve. The present disclosure can support the bearing by using the positioning sleeve and the fixing member, so that the middle hole in the bearing seat can be processed and formed at one time, so as to ensure the coaxiality of the lead screw and the bearing, and prevent the lead screw from being subjected to radial pressure to affect the stability of the collimation assembly.

Description

Technical Field

[0001] The present disclosure relates to the technical field of electron linear accelerators, in particular to the field of non-destructive testing using accelerators as radiation sources, and more particularly to an external collimator and a control method for non-destructive testing accelerators. Background Art

[0002] Electron linear accelerators for non-destructive testing usually use external collimators to adjust the irradiation field. The main part of the collimator is usually made of a material that has a blocking / absorbing effect on X-rays. Through a certain structural design, it can block a part of the X-rays and allow the other part of the X-rays to pass through to achieve the purpose of collimation. For the X-rays that need to be blocked, the blocking effect is determined by the material and thickness of the collimator. In different non-destructive testing systems, the collimator collimates the X-ray beam into different shapes. For example, in radiography, the radiation field usually needs to be collimated into a square cone, and in scanning imaging, the radiation field usually needs to be collimated into a thin fan shape. In front of the detector, the collimator is usually designed according to the shape of the detector to block the scattered X-rays and let the detector only absorb the X-rays that are transmitted forward through the object. The collimator has a very important influence on the photography or imaging effect of the non-destructive testing system and is one of the important components in the non-destructive testing system.

[0003] The commonly used collimators currently have the problem of poor coordination between the lead screw and the bearing assembly. Specifically, the existing bearing assembly generally includes a bearing seat and two bearings, wherein the middle hole of the bearing seat has a step, and the step is used to bidirectionally support the two bearings located in the middle hole. When machining the middle hole of the bearing seat, the bearing seat needs to be clamped twice in order to leave a step, that is, holes need to be dug from both ends of the middle hole. In actual application, it was found that after constructing the bearing assembly in the above manner, the collimation block is easily subject to resistance when moving, resulting in a series of problems such as inaccurate opening angle of the collimator, overload of the drive motor, and burnout of the drive circuit. Summary of the invention

[0004] In one aspect, the present disclosure provides an external collimator for a non-destructive testing accelerator, comprising: a mounting frame; a lead screw connected to the mounting frame; a driving device for driving the lead screw to rotate; a collimation assembly, the collimation assembly being connected to the lead screw, and the collimation assembly can be driven by the lead screw to adjust the irradiation angle; and a bearing assembly, the bearing assembly being arranged between the lead screw and the mounting frame and used to support the rotation of the lead screw, wherein the bearing assembly comprises: a bearing seat, the bearing seat being connected to the mounting seat, the bearing seat being provided with a middle hole passing through the bearing seat and a positioning hole extending radially along the middle hole; a bearing, the bearing being arranged in the middle hole and used to cooperate with the rotation of the lead screw; a positioning sleeve, the positioning sleeve being embedded in the middle hole and abutting against the bearing, used to support the bearing; and a fixing member, the fixing member can pass through the positioning hole and be connected to the positioning sleeve, and is used to fix the positioning sleeve in the middle hole.

[0005] According to an embodiment of the present disclosure, the bearing assembly includes two bearings, the two bearings are distributed along the axial direction of the middle hole, and the positioning hole is arranged between the two bearings.

[0006] When the positioning sleeve is embedded in the middle hole, two sides of the positioning sleeve are respectively against the two bearings.

[0007] According to an embodiment of the present disclosure, the minimum distance between the positioning sleeve and the central axis of the middle hole is not less than the inner diameter of the bearing.

[0008] According to an embodiment of the present disclosure, the bearing assembly includes at least two positioning holes, and the at least two positioning holes are evenly distributed along the circumference of the middle hole, and each of the positioning holes cooperates with one of the fixing members.

[0009] According to an embodiment of the present disclosure, the external collimator further includes an FPGA device for controlling the direction and distance of movement of the collimation assembly.

[0010] According to an embodiment of the present disclosure, the collimation assembly includes: a first group of collimation parts, the first group of collimation parts is connected to the lead screw, the first group of collimation parts has two collimation blocks that can be driven by the lead screw to move along a first direction; and a second group of collimation parts, the second group of collimation parts is connected to the lead screw, the second group of collimation parts has two collimation blocks that can be driven by the lead screw to move along a second direction; wherein the first direction is perpendicular to the second direction.

[0011] According to an embodiment of the present disclosure, the first group of collimators and the second group of collimators are arranged in sequence along the ray irradiation direction of the accelerator.

[0012] According to an embodiment of the present disclosure, the external collimator further comprises a guide rail, the guide rail is connected to the mounting frame, and the collimation block can slide along the guide rail when driven by the lead screw.

[0013] According to an embodiment of the present disclosure, the guide rail is constructed in an arc shape whose center coincides with the ray source point.

[0014] In another aspect, the present disclosure provides a control method for an external collimator for a nondestructive testing accelerator, comprising: presetting an illumination angle of the external collimator; acquiring a working state parameter of the driving device based on the illumination angle; controlling the driving device to operate according to the working state parameter to drive the collimation assembly to move to a target position so that the collimation assembly forms an illumination angle that meets the preset angle; and disconnecting the driving device when the collimation assembly reaches the target position.

[0015] According to the external collimator and control method for nondestructive testing accelerators of the disclosed embodiments, the collimation assembly can be driven to move by at least the driving device and the lead screw, so as to adjust the irradiation field. At the same time, since the positioning sleeve can cooperate with the positioning hole and the fixing part to support the bearing, there is no need to separately set a step for supporting the bearing in the middle hole of the bearing seat, so that the middle hole in the bearing seat can be machined and formed at one time, that is, only one clamping is required when machining the middle hole of the bearing seat. Therefore, when the bearing is installed in the middle hole, the lead screw and the bearing can be kept coaxial, so that the lead screw will not be subjected to radial pressure. Furthermore, the collimation assembly will not be subjected to resistance when being driven by the lead screw, thereby avoiding a series of problems such as inaccurate opening angle of the external collimator, overload of the driving device, and burning of the driving circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other objects and advantages of the present disclosure will be apparent from the following description of the present disclosure with reference to the accompanying drawings, and will help to have a comprehensive understanding of the present disclosure.

[0017] Figure 1 It is a schematic diagram of the three-dimensional structure of an external collimator for a non-destructive testing accelerator according to an embodiment of the present disclosure.

[0018] Figure 2 is a front view schematic diagram of an external collimator for a nondestructive testing accelerator according to an embodiment of the present disclosure.

[0019] Figure 3a yes Figure 2 A partial enlarged view of part A, wherein part A illustrates a cross-sectional view of the mounting frame, the lead screw and the bearing assembly.

[0020] Figure 3b is Figure 3a Schematic diagram with the lead screw hidden from view.

[0021] Figure 4 is a schematic rear view of an external collimator for a nondestructive testing accelerator according to an embodiment of the present disclosure.

[0022] Figure 5 It is a flow chart of a control method for an external collimator of a nondestructive testing accelerator according to an embodiment of the present disclosure.

[0023] In the figure, an external collimator 100, a mounting frame 110, a lead screw 120, a driving device 130, a collimation assembly 140, a first group of collimation parts 141, a second group of collimation parts 142, a collimation block 143, a bearing assembly 150, a bearing seat 151, an intermediate hole 1511, a positioning hole 1512, a bearing 152, a positioning sleeve 153, a threaded hole 1531, a fixing member 154, a guide rail 160, a transmission fixing device 171, a sliding fixing device 172, a main transmission wheel 181, and a slave transmission wheel 182.

[0024] It should be noted that, for the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the sizes of structures or regions may be enlarged or reduced, that is, these drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0026] Unless otherwise defined, the technical terms or scientific terms used in this disclosure should be understood by ordinary technicians in the field. "First", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprising" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0027] In this document, unless otherwise specified, directional terms such as "upper", "lower", "left", "right", "inner", "outer", etc. are used to indicate the orientation or positional relationship based on the drawings, and are only for the convenience of describing the present disclosure, and do not indicate or imply that the device, element or component referred to must have a specific orientation, be constructed or operate in a specific orientation. It should be understood that when the absolute position of the described object changes, the relative positional relationship they represent may also change accordingly. Therefore, these directional terms should not be understood as limiting the present disclosure.

[0028] An embodiment of the present disclosure provides an external collimator for a non-destructive testing accelerator, comprising: a mounting frame; a lead screw, which is connected to the mounting frame; a driving device, which is used to drive the lead screw to rotate; a collimation assembly, which is connected to the lead screw and can be driven by the lead screw to adjust the irradiation angle; and a bearing assembly, which is arranged between the lead screw and the mounting frame and is used to support the rotation of the lead screw, wherein the bearing assembly comprises: a bearing seat, which is connected to the mounting seat, and is provided with a middle hole passing through the bearing seat and a positioning hole extending radially along the middle hole; a bearing, which is arranged in the middle hole and is used to cooperate with the rotation of the lead screw; a positioning sleeve, which is embedded in the middle hole and abuts against the bearing and is used to support the bearing; and a fixing member, which can pass through the positioning hole and is connected to the positioning sleeve and is used to fix the positioning sleeve in the middle hole. In the embodiments of the present disclosure, the bearing assembly can be used to rotatably set the screw on the mounting frame, so that the drive device and the screw can be used to drive the alignment assembly to move, and a positioning hole is opened on the side wall of the middle hole of the bearing seat. When the bearing and the positioning sleeve are placed in the middle hole, the fixing part can be embedded in the positioning hole to fix the positioning sleeve in the middle hole, so that the positioning sleeve can support the bearing and ensure the stability of the bearing. Through the above-mentioned structural design, the middle hole in the bearing seat can be processed and formed at one time, which can ensure that the screw is coaxial with the bearing in the middle hole. At this time, the screw will not be subjected to radial pressure, thereby ensuring the stability of the collimation assembly when being driven.

[0029] Figure 1 It is a schematic diagram of the three-dimensional structure of an external collimator for a non-destructive testing accelerator according to an embodiment of the present disclosure. Figure 2 is a front view schematic diagram of an external collimator for a nondestructive testing accelerator according to an embodiment of the present disclosure. Figure 3a yes Figure 2 A partial enlarged view of part A, wherein part A illustrates a cross-sectional view of the mounting frame, the lead screw and the bearing assembly. Figure 3b is Figure 3a Schematic diagram with the lead screw hidden from view. Figure 4 is a schematic rear view of an external collimator for a nondestructive testing accelerator according to an embodiment of the present disclosure.

[0030] like Figures 1 to 4As shown, the external collimator 100 for a nondestructive testing accelerator according to an embodiment of the present disclosure may include a mounting frame 110, a lead screw 120, a drive device 130, a collimation assembly 140 and a bearing assembly 150. The external collimator 100 is disposed outside the accelerator and is used to collimate the outgoing rays of the accelerator.

[0031] The mounting frame 110 is used to support various components of the external collimator 100 . In the present embodiment, the mounting frame 110 is constructed as a substantially frame-shaped structure, and other components are distributed on the mounting frame 110 .

[0032] The lead screw 120 is rotatably connected to the mounting bracket 110 . The lead screw 120 is mainly used to drive the collimation assembly 140 to move, so as to adjust the irradiation angle of the collimation assembly 140 , that is, to adjust the irradiation field of the external collimator 100 .

[0033] The driving device 130 is disposed on the mounting frame 110, and the output end of the driving device 130 is connected to the lead screw 120 for driving the lead screw 120 to rotate. For example, the driving device 130 may be a stepping motor, and the lead screw 120 may be driven by controlling the number of steps and direction of the stepping motor to thereby drive the collimation assembly 140 to move to a specified position. In other optional embodiments, the driving device 130 may also be hydraulically driven, pneumatically driven, etc., and the distribution position of the driving device 130 may not be limited to the form shown in the drawings, as long as it can drive the lead screw 120 to rotate.

[0034] The collimation assembly 140 is located in the gap formed by the mounting frame 110 and is connected to the lead screw 120. The mounting frame 110 can protect the collimation assembly 140. The collimation assembly 140 is made of radiation shielding material. Under the driving action of the driving device 130 and the lead screw 120, the collimation assembly 140 can move along the lead screw 120 to shield part of the rays emitted by the accelerator, thereby adjusting the irradiation angle of the rays.

[0035] The bearing assembly 150 is disposed between the lead screw 120 and the mounting frame 110 to support the rotation of the lead screw 120. Specifically, the bearing assembly 150 may include a bearing seat 151, a bearing 152, a positioning sleeve 153 and a fixing member 154.

[0036] The bearing seat 151 is connected to the mounting frame 110. For example, the bearing seat 151 and the mounting frame 110 may be an integrated structure, or the bearing seat 151 may be detachably connected to the mounting frame 110. An intermediate hole 1511 is provided in the bearing seat 151. The intermediate hole 1511 is a cylindrical hole and passes through the bearing seat 151 for the screw 120 to pass through. A positioning hole 1512 is provided on the side of the intermediate hole 1511. For example, the positioning hole 1512 may be a cylindrical hole. The positioning hole 1512 extends along the radial direction of the intermediate hole 1511 and passes through the bearing seat 151. That is, the positioning hole 1512 communicates with the intermediate hole 1511 and the outside of the bearing seat 151.

[0037] The bearing 152 is arranged in the middle hole 1511. After the bearing 152 is installed in the middle hole 1511, the outer peripheral side of the bearing 152 abuts against the inner peripheral side of the middle hole 1511, and the inner peripheral side of the bearing 152 abuts against the lead screw 120, so as to cooperate with the lead screw 120 to rotate. That is, in the radial direction of the bearing 152, the bearing seat 151 is used to support the bearing 152. Among them, the outer peripheral side of the bearing 152 refers to the outer peripheral surface of the bearing 152, the inner peripheral side of the bearing 152 refers to the inner peripheral surface of the bearing 152, and the inner peripheral side of the middle hole 1511 refers to the inner wall surface of the middle hole 1511, which will not be described in detail later in this article.

[0038] The shape of the positioning sleeve 153 is configured to match the shape of the middle hole 1511. For example, when the middle hole 1511 is a cylindrical hole, the positioning sleeve 153 may be in the shape of a ring. In the embodiment of the present disclosure, when the positioning sleeve 153 is embedded in the middle hole 1511, the outer circumference of the positioning sleeve 153 abuts against the inner circumference of the middle hole 1511, that is, the outer diameter of the positioning sleeve 153 is substantially equal to the inner diameter of the middle hole 1511.

[0039] The shape of the fixing member 154 is configured to match the shape of the positioning hole 1512. For example, when the positioning hole 1512 is a cylindrical hole, the fixing member 154 can be in the shape of a cylinder. The fixing member 154 can extend from the outside of the bearing seat 151 into the positioning hole 1512, and is connected to the positioning sleeve 153 after passing through the positioning hole 1512. For example, the fixing member 154 can be configured to be similar to a screw structure (i.e., an external thread is provided on the surface of the fixing member 154), and the inner wall of the positioning hole 1512 is provided with an internal thread that matches the fixing member 154. Accordingly, the positioning sleeve 153 is provided with a threaded hole 1531 that matches the fixing member 154. At this time, by rotating the fixing member 154, the fixing member 154 can pass through the positioning hole 1512 and be connected to the threaded hole 1531 on the positioning sleeve 153, so that the positioning sleeve 153 is fixed in the middle hole 1511. Furthermore, when the positioning sleeve 153 is installed in the middle hole 1511 , the side surface of the positioning sleeve 153 abuts against the end surface of the bearing 152 , that is, the positioning sleeve 153 supports the bearing 152 in the axial direction of the bearing 152 .

[0040] The embodiment of the present disclosure provides an external collimator 100 for nondestructive testing of an electron linear accelerator, which can drive the collimation assembly 140 to move through the driving device 130 and the lead screw 120, so as to adjust the irradiation field. At the same time, since the positioning sleeve 153 can cooperate with the positioning hole 1512 and the fixing member 154 to support the bearing 152, it is not necessary to separately set a step for supporting the bearing 152 in the middle hole 1511, and the middle hole 1511 in the bearing seat 151 can be processed and formed at one time, that is, only one clamping is required when processing the middle hole 1511 of the bearing seat 151. Therefore, when the bearing 152 is installed in the middle hole 1511, the lead screw 120 can be kept coaxial with the bearing 152, and the lead screw 120 will not be subjected to radial pressure. Furthermore, the collimation assembly 140 will not be subjected to resistance when being driven by the lead screw 120, thereby avoiding a series of problems such as inaccurate opening angle of the external collimator 100, overload of the driving device 130, and burnout of the driving circuit.

[0041] According to an embodiment of the present disclosure, the bearing assembly 150 may include two bearings 152, and the two bearings 152 are distributed along the axial direction of the middle hole 1511. The positioning hole 1512 is arranged between the two bearings 152. When the positioning sleeve 153 is embedded in the middle hole 1511, the two sides of the positioning sleeve 153 are respectively against the two bearings 152. The positioning sleeve 153 can support the bearing 152 to ensure the stability of the bearing 152.

[0042] According to an embodiment of the present disclosure, the bearing assembly 150 includes at least two positioning holes 1512, and the at least two positioning holes 1512 are evenly distributed along the circumference of the middle hole 1511, and each positioning hole 1512 is matched with a fixing member 154. By evenly arranging multiple positioning holes 1512 and fixing members 154 around the circumference of the middle hole 1511, the positioning sleeve 153 can be fixed from multiple angles, thereby ensuring that the positioning sleeve 153 is firmly connected to the bearing seat 151.

[0043] For example, Figure 2 and Figure 3a , Figure 3b As shown, a plurality of bearing assemblies 150 may be arranged between the mounting frame 110 and the lead screw 120, and each bearing assembly 150 may include a bearing seat 151, two bearings 152, a positioning sleeve 153 and four fixing members 154. Figure 3a and Figure 3bFrom the perspective of , the two bearings 152 included in the bearing assembly 150 are respectively located at the top and bottom of the positioning sleeve 153, and the two bearings 152 are both annular. When the lead screw 120 is connected to the mounting frame 110 through the bearing assembly 150, the bearings 152 are sleeved on the outer periphery of the lead screw 120. The bearing seat 151 is provided with four positioning holes 1512 for cooperating with the fixing member 154. The four positioning holes 1512 and the four fixing members 154 are evenly distributed along the circumference of the middle hole 1511. Figure 3a and Figure 3b The fixing member 154 and the positioning hole 1512 on the left and right sides are shown in FIG. Figure 3a and Figure 3b The front and rear sides of the bearing assembly 150 are also provided with fixing members 154 and positioning holes 1512 respectively from the perspective of the bearing assembly 150. The bearing assembly 150 is mainly responsible for the support and rotation of the lead screw 120. The positioning sleeve 153 is placed between the two bearings 152, and the two bearings 152 each bear thrust in opposite directions. During installation, a bearing 152 is first placed in the middle hole 1511, and the bearing 152 will abut against the bottom of the bearing seat 151, that is, the bearing 152 is naturally in place, and then the positioning sleeve 153 is placed, and the positioning sleeve 153 is fixed in the middle hole 1511 with the fixing member 154, and then another bearing 152 is placed. Finally, the bearing assembly 150 is fixed to the mounting frame 110 after the lead screw 120 is covered. Therefore, the positioning sleeve 153 can be used to support the two bearings 152, ensuring the stable connection between the bearing 152 and the lead screw 120, and because the middle hole 1511 can be processed and formed at one time, the coaxiality of the lead screw 120 and the two bearings 152 can be ensured, and the lead screw 120 is prevented from being subjected to radial pressure.

[0044] It should be noted that, in other optional embodiments, the bearing assembly 150 may include more bearings 152. For example, the bearing assembly 150 may include three, four, five bearings 152, etc. Accordingly, positioning sleeves 153, positioning holes 1512 and fixing members 154 may be provided between adjacent bearings 152 to form a stable support for all bearings 152.

[0045] According to an embodiment of the present disclosure, the minimum distance between the positioning sleeve 153 and the central axis of the middle hole 1511 is not less than the inner diameter of the bearing 152. Figure 3a As shown, when the locating sleeve 153 is embedded in the middle hole 1511, the minimum distance between the locating sleeve 153 and the central axis of the middle hole 1511 is the distance between the end face of the locating sleeve 153 at one end close to the central axis of the middle hole 1511 and the central axis of the middle hole 1511. The minimum distance should not be less than the inner diameter of the bearing 152 to avoid interference between the locating sleeve 153 and the screw 120 after being installed in the middle hole 1511, thereby affecting the rotation of the screw 120.

[0046] According to an embodiment of the present disclosure, the outer collimator 100 further includes a PFGA device for controlling the moving direction and distance of the collimating assembly 140. Specifically, the position of the collimating assembly 140 after movement can be controlled by controlling the output power of the driving device 130.

[0047] At present, the commonly used collimator is realized by PLC (Programmable Logic Controller) control. However, as the electron linear accelerator is a radiation source, the radiation dose in the accelerator head is relatively high, and the PLC has poor radiation resistance. It is easy to fail after a period of use, resulting in the inability to control the collimator.

[0048] In the embodiments of the present disclosure, an external collimator control unit using FPGA (Field Programmable Gate Array) as a logic device is used to replace the original PLC, which can improve radiation resistance. For example, the IGLOO series FPGA can be used, which has ultra-low power consumption and a unique Flash*Freeze sleep mode. In this mode, its minimum power consumption is small and the state of RAM (random access memory) and registers can be saved; and the FPGA based on the Flash structure has high reliability compared to the PLC with SRAM (Static Random Access Memory) structure. This is because the high-energy ions in the atmosphere will cause state changes in the process of colliding with the SRAM structure transistor, thereby causing errors and failures, and the change of the state of the transistor of the Flash structure requires a certain voltage, and general high-energy ions cannot reach this level, so it is suitable for accelerator applications. In this way, the radiation resistance problem of the control power supply of the external collimator 100 can be solved.

[0049] According to an embodiment of the present disclosure, the collimation assembly 140 may include a first group of collimators 141 and a second group of collimators 142, both of which are driven by the lead screw 120 and the driving device 130. The first group of collimators 141 has two collimators 143 that can be driven by the lead screw 120 to move along a first direction, and the second group of collimators 142 has two collimators 143 that can be driven by the lead screw 120 to move along a second direction, wherein the first direction is perpendicular to the second direction. Figure 2 As shown, the first direction can be a horizontal direction, and the second direction can be a vertical direction, that is, the two collimating blocks 143 included in the first group of collimating parts 141 can move in the horizontal direction, and the two collimating blocks 143 included in the second group of collimating parts 142 can move in the vertical direction, thereby satisfying the need to arbitrarily adjust the irradiation field in the vertical and horizontal directions.

[0050] According to the embodiment of the present disclosure, the first group of collimators 141 and the second group of collimators 142 are sequentially arranged along the irradiation direction of the accelerator, and the rays will pass through between the first group of collimators 141 and the second group of collimators 142. Therefore, the four collimating blocks 143 included in the first group of collimators 141 and the second group of collimators 142 can reciprocate in the area with the accelerator ray as the center point, respectively, upward, downward, left, and right, so that the movement combination of the four collimating blocks 143 can arbitrarily define the ray field in a two-dimensional area.

[0051] According to an embodiment of the present disclosure, the external collimator 100 also includes a guide rail 160, which is connected to the mounting frame 110. The collimation block 143 can slide along the guide rail 160 driven by the lead screw 120. The guide rail 160 can guide the movement trajectory of the collimation assembly 140 to facilitate adjustment of the irradiation field.

[0052] For example, Figure 1 As shown, the guide rail 160 and the lead screw 120 are respectively mounted in pairs on the edge of the mounting frame 110. The external collimator 100 also includes a transmission fixture 171 and a sliding fixture 172. The collimation block 143 is mounted on the lead screw 120 through a pair of transmission fixtures 171 on both sides thereof. The transmission fixture 171 is tightly matched with the lead screw 120. The lead screw 120 bears the weight of the collimation block 143 through the transmission fixture 171 and drives the collimation block 143 to move. A pair of sliding fixtures 172 are respectively mounted on both sides of the collimation block 143. Each pair of sliding fixtures 172 is in close contact with a guide rail 160 between them. The sliding fixture 172 and the guide rail 160 can slide. During the movement of the collimation block 143, due to the action of the sliding fixture 172, the collimation block 143 will strictly move along the track of the guide rail 160.

[0053] Optionally, the guide rail 160 is constructed as an arc whose center coincides with the ray source point, so that during the movement of the collimation block 143, the corner point of its opening angle remains at the ray source point, thereby improving the photographic quality and imaging quality.

[0054] It can be understood that in some embodiments, the guide rail 160 can also be constructed into other shapes, such as a straight line, etc., which can be determined according to the requirements of the irradiation field.

[0055] In some exemplary embodiments, the outer collimator 100 may further include a transmission device, which may include a main transmission wheel 181, a slave transmission wheel 182, and a transmission connection device. Figure 1As shown, the mounting frame 110 is provided with a lead screw 120 that cooperates with each collimation block 143, and the end of the lead screw 120 extends from the side of the mounting frame 110. A main transmission wheel 181 and a slave transmission wheel 182 are respectively installed on each pair of lead screws 120. A transmission connection device (such as a pulley, a chain, etc.) is provided between the driving device 130, the main transmission wheel 181, and the slave transmission wheel 182, so that they can coordinate under certain conditions. Specifically, the driving device 130 can drive the main transmission wheel 181, and the main transmission wheel 181 can drive the slave transmission wheel 182. The main transmission wheel 181 and the slave transmission wheel 182 can be used to synchronously drive a pair of lead screws 120 to move, so that the collimation block 143 moves, and the range of the ray field is adjusted.

[0056] In addition, a limiting device may be installed on the mounting frame 110. For example, the limiting device may be a solid protruding block, as long as it can block the alignment block 143. The limiting devices are installed in pairs on the inner side of the frame structure of the mounting frame 110, and the installation position can be adjusted appropriately. For example, when four alignment blocks 143 are provided, limiting devices may be provided on both sides of each alignment block 143, for a total of eight limiting devices. When the alignment block 143 moves to the limit position defined by the system, the edge of the alignment block 143 touches the limiting device, thereby limiting the alignment block 143.

[0057] Figure 5 It is a flow chart of a control method for an external collimator of a nondestructive testing accelerator according to an embodiment of the present disclosure.

[0058] like Figure 5 As shown, another embodiment of the present disclosure further provides a control method for an external collimator of a non-destructive testing accelerator, the control method comprising:

[0059] S510, presetting an illumination angle of the external collimator 100, wherein the illumination angle is determined according to actual working conditions.

[0060] S520, based on the preset irradiation angle, obtain the working state parameters of the driving device 130. Specifically, it is possible to first determine where each collimating block 143 should move to according to the irradiation angle of the outer collimator 100, and then determine the working state parameters of the driving device 130 according to the moving direction and distance of each collimating block 143, wherein the working state parameters refer to the output power of the driving device 130, such as the number of steps and direction of the stepping motor.

[0061] S530, controlling the driving device 130 to operate according to the working state parameters to drive the collimating assembly 140 to move to a target position, where the collimating assembly 140 forms an irradiation angle that meets a preset value.

[0062] S540, when the collimating assembly 140 reaches the target position, the driving device 130 is disconnected to control the external collimator 100 to reach a preset irradiation angle.

[0063] The external collimator and control method for a nondestructive testing accelerator according to the embodiments of the present disclosure have at least one of the following technical effects:

[0064] (1) The positioning sleeve 153 can provide stable support for the bearing 152, and the middle hole 1511 of the bearing seat 151 can be formed in one step to ensure that the screw 120 is coaxial with the bearing 152, so that the screw 120 will not be subjected to radial pressure, ensuring that the screw 120 stably drives the alignment block 143 to move.

[0065] (2) Using FPGA control drive, compared with PLC that is not resistant to radiation, FPGA has improved radiation resistance and greatly reduced failure rate.

[0066] (3) The driving device 130 and the lead screw 120 can be used to drive the collimation block 143 to move to a specified position to facilitate adjustment of the irradiation field.

[0067] Although some embodiments according to the overall technical concept of the present disclosure have been shown and described, those skilled in the art will appreciate that changes may be made to these embodiments without departing from the principles and spirit of the overall technical concept of the present disclosure, and the scope of the present disclosure is defined by the claims and their equivalents.

Claims

1. An external collimator for a nondestructive testing accelerator, characterized in that: include: Mounting frame; A lead screw connected to the mounting frame; A driving device, used for driving the lead screw to rotate; A collimation assembly, the collimation assembly is connected to the lead screw, and the collimation assembly can be driven by the lead screw to adjust the irradiation angle; as well as A bearing assembly, the bearing assembly is arranged between the lead screw and the mounting frame, and is used to support the lead screw to rotate. Wherein, the bearing assembly comprises: A bearing seat, the bearing seat is connected to the mounting frame, and the bearing seat is provided with a middle hole penetrating the bearing seat and a positioning hole extending radially along the middle hole; A bearing, the bearing being arranged in the middle hole and being used for rotating with the lead screw; a positioning sleeve, the positioning sleeve being embedded in the middle hole and abutting against the bearing to support the bearing; and A fixing piece, which can pass through the positioning hole and be connected to the positioning sleeve, is used to fix the positioning sleeve in the middle hole.

2. The external collimator for nondestructive testing accelerator according to claim 1, characterized in that: The bearing assembly includes two bearings, the two bearings are distributed along the axial direction of the middle hole, and the positioning hole is arranged between the two bearings. When the positioning sleeve is embedded in the middle hole, two sides of the positioning sleeve are respectively against the two bearings.

3. The external collimator for nondestructive testing accelerator according to claim 2, characterized in that: The minimum distance between the positioning sleeve and the central axis of the middle hole is not less than the inner diameter of the bearing.

4. The external collimator for nondestructive testing accelerator according to claim 1, characterized in that: The bearing assembly comprises at least two positioning holes, and the at least two positioning holes are evenly distributed along the circumference of the middle hole, and each of the positioning holes cooperates with one of the fixing members.

5. The external collimator for nondestructive testing accelerator according to claim 1, characterized in that: The outer collimator also includes an FPGA device for controlling the direction and distance of movement of the collimating component.

6. The external collimator for a non-destructive testing accelerator according to any one of claims 1 to 5, characterized in that: The collimation assembly comprises: A first group of collimating members, the first group of collimating members being connected to the lead screw, the first group of collimating members having two collimating blocks that can be driven by the lead screw to move along a first direction; and A second group of collimating members, the second group of collimating members being connected to the lead screw, the second group of collimating members having two collimating blocks that can be driven by the lead screw to move along a second direction; The first direction is perpendicular to the second direction.

7. The external collimator for nondestructive testing accelerator according to claim 6, characterized in that: The first group of collimating elements and the second group of collimating elements are arranged in sequence along the ray irradiation direction of the accelerator.

8. The external collimator for non-destructive testing accelerator according to claim 7, characterized in that: The external collimator also includes a guide rail, which is connected to the mounting frame, and the collimation block can slide along the guide rail driven by the lead screw.

9. The external collimator for non-destructive testing accelerator according to claim 8, characterized in that: The guide rail is constructed in the shape of an arc whose center coincides with the radiation source point.

10. A control method for an external collimator for a non-destructive testing accelerator using any one of claims 1 to 9, characterized in that: include: Presetting the illumination angle of the outer collimator; Based on the irradiation angle, obtaining a working state parameter of the driving device; Controlling the driving device to operate according to the working state parameters to drive the collimating assembly to move to a target position so that the collimating assembly forms an irradiation angle that meets a preset value; as well as When the collimating assembly reaches the target position, the driving device is disconnected.

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