Laser feed-in structure of electron linear accelerator
By introducing horizontal and angle adjustment plates and observation window components into the electronic linear accelerator, the laser feed instability problem caused by mechanical processing errors is solved, efficient laser beam adjustment and precise reflection of electron beam masses are achieved, and operation safety and efficiency are improved.
Patent Information
- Application Number
- CN202510498055.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-21
- Publication Date
- 2025-07-25
AI Technical Summary
The existing laser feed structure of electronic linear accelerator is difficult to achieve stability and repeat positioning accuracy under the accumulation of mechanical processing errors, and the adjustment process is complex, affecting the quality of the laser beam and the transmission of electron beam clusters.
The structural design includes a horizontal adjustment plate, a horizontal position adjustment plate and an angle direction adjustment plate is adopted, combined with the observation window components and the dividing lines, to achieve convenient adjustment and accurate verification of the lens, ensuring the stability and accuracy of laser feeding.
It improves the convenience of adjusting the laser feed line, enhances the accuracy and stability of lens installation, reduces the risk of visual damage to the operator, and improves the efficiency of the laser feed process.
Smart Images
Figure CN120379127A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of electron linear accelerators, and particularly to a laser feeding structure for an electron linear accelerator. Background Art
[0002] The principle of the laser feeding structure of the accelerator electron gun is to introduce a laser beam with a certain energy at a certain angle onto the surface of the cathode material through a certain structure to ensure the effect of laser beam bombardment and obtain electron bunches that meet the requirements. Moreover, the environment for feeding the laser is generally an ultra-high vacuum environment, and its vacuum degree can reach 1×10⁻⁸ Pa. The laser needs to go through multiple structural conversions during feeding to introduce the laser beam onto the cathode surface. Due to the machining accuracy and error accumulation of mechanical processing, there will be a large difference between the theoretical size and the actual size. Therefore, there are high requirements for the stability and repeat positioning accuracy of the structure, and it needs to be relatively convenient during the adjustment of the structure.
[0003] Currently, there are few domestic projects on photocathode electron guns. The laser feeding method is to use a transparent quartz window structure to introduce the laser, and then it is introduced onto the photocathode surface in two ways. One is to adjust the incident angle of the laser in the atmosphere environment and then directly introduce it onto the photocathode surface. In this way, both the laser beam and the cathode material are within the visible range, and it is very easy for the laser beam to be aligned with the cathode material. The disadvantage of this structure is that the angle between the laser introduction line and the cathode surface is too small, and the cathode surface is unevenly bombarded by the laser, which will affect the quality of the electron bunches and increase the difficulty of the subsequent bunch transmission and bunching. Another way is to adjust the incident angle of the laser in the atmosphere environment and reflect it onto the photocathode surface through a metal mirror in an ultra-high vacuum, so as to obtain an incident angle that is almost perpendicular to the photocathode material, and the conditions for obtaining better electron bunches are achieved structurally. However, the distance between the cathode material and the laser introduction point in this structure exceeds 400 mm, and the intermediate process of introduction is in the vacuum tube, which is extremely likely to have problems such as the laser feeding mirror not being adjusted in place and subsequent stability, and it is easy to contaminate the surface of the laser feeding mirror during multiple adjustments, thereby reducing the quality of the laser beam. Summary of the Invention
[0004] In order to improve the angle during laser feeding, the repeat positioning accuracy, and the adjustment difficulty of the laser feeding mirror, this application provides a laser feeding structure for an electron linear accelerator.
[0005] A laser feeding structure for an electron linear accelerator provided by this application adopts the following technical solutions: A laser feeding structure for an electron linear accelerator includes a fixed base and a vacuum chamber. The vacuum chamber is provided with: A first port and a second port, which are coaxially arranged and are respectively used for the laser beam to shoot out and bombard the cathode plate and the reflected electron bunches to be led out; The third ports, there are three of them and they are distributed on the left side, right side and upper side of the vacuum chamber; The observation window assembly is arranged on the third ports, and in each of the two third ports located on the left side and the right side, there are provided: A horizontal adjustment plate, which is installed on the third port; A lateral position adjustment plate, which is installed on the horizontal adjustment plate; An angular direction adjustment plate, which is installed on the lateral position adjustment plate and is arranged at an angle with the lateral position adjustment plate; and A lens, which is installed on the side of the angular direction adjustment plate close to the first port, and there is a bunch channel for the electron beam bunch to pass through between the two lenses on the two opposite third ports; external laser light enters the lens from one of the third ports provided with a lens.
[0006] Furthermore, the horizontal adjustment plate is arranged as a cylindrical structure and fits on the inner wall of the third port, and a plurality of waist-shaped arc holes are opened at its end. The horizontal adjustment plate is bolted and fixed on the third port through bolts passing through the waist-shaped arc holes.
[0007] Furthermore, a plurality of oblong holes are opened on the lateral position adjustment plate along the axial direction of the horizontal adjustment plate. The lateral position adjustment plate is bolted and fixed on the horizontal adjustment plate through bolts passing through the oblong holes.
[0008] Furthermore, the angular direction adjustment plate is hinged to one end of the lateral position adjustment plate extending into the inner cavity of the vacuum chamber, and is bolted and fixed on the lateral position adjustment plate through bolts passing through the hinge part of the two.
[0009] Furthermore, a cut surface is provided at one end of the lens close to the bunch channel.
[0010] Furthermore, the observation window assembly includes: A sealing flange, which is bolted and fixed at the end of the third port; An observation window piece, which is embedded in the sealing flange; A pressing plate, which is bolted and fixed on the sealing flange and is used to press the observation window piece; and A sealing plate, which is arranged between the observation window piece and the pressing plate or the sealing flange.
[0011] Furthermore, a crosshair is provided on the observation window piece in the other third port opposite to the third port where the external laser light enters.
[0012] Furthermore, a polarizing film layer is provided on the observation window piece provided with the crosshair.
[0013] Furthermore, adjustment scales are provided in the adjustment directions of the horizontal adjustment plate, the lateral position adjustment plate, and the angular direction adjustment plate.
[0014] Furthermore, it further includes: A bottom plate for mounting the vacuum chamber; A height adjustment structure provided between the bottom plate and the fixed base for adjusting the height and levelness of the bottom plate.
[0015] In summary, the present application includes at least one of the following beneficial technical effects: 1. Through the horizontal adjustment plate, the lateral position adjustment plate, and the angular direction adjustment plate in the third port, the installation height center position, the horizontal center position of the lens, and the exact center position of the reflected laser beam on the cathode plate can be adjusted conveniently and stably, effectively compensating for the influence caused by the cumulative error of machining, and improving the convenience of adjusting the laser feeding line; 2. By providing graduation lines on the viewing window through which the electron beam bunch is reflected, the landing point of the electron beam bunch reflected on the viewing window can be accurately calibrated, and the installation position of the lens can be conveniently visually observed and adjusted; further providing graduation lines on the viewing window through which external laser light enters, the mirror image degree of the two lenses can also be calibrated by the landing point of the incident laser beam on the left viewing window and the landing point of the reflected electron beam bunch on the right viewing window; 3. By providing a polarizing film layer on the viewing window provided with graduation lines, stray light can be eliminated, and the damage to the human eye caused by the reflected electron beam bunch irradiating on the human eye can be reduced, enabling the operator to observe the landing point of the reflected electron beam bunch for a long time within a certain period, and improving the calibration efficiency of the lens installation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0017] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application; Figure 2 It is a schematic diagram of a partial cross-sectional structure of an embodiment of the present application; Figure 3 It is a laser beam feeding path diagram of an embodiment of the present application; Figure 4 It is a schematic diagram of the structure of a viewing window assembly provided with graduation lines in an embodiment of the present application.
[0018] Reference numerals: 11. Fixed base; 12. Bottom plate; 13. Height adjustment structure; 2. Vacuum chamber; 21. First port; 22. Second port; 23. Third port; 24. Bunch channel; 3. Horizontal adjustment plate; 31. Waist arc hole; 4. Lateral position adjustment plate; 41. Oval long hole; 5. Angular direction adjustment plate; 6. Lens; 61. Cut surface; 71. Sealing flange; 72. Observation window pane; 73. Pressure plate; 74. Sealing plate; 8. Reticle. Detailed implementation manners
[0019] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention.
[0020] Refer to Figure 1 、 Figure 2 and Figure 3 , an embodiment of the present application discloses a laser feeding structure for an electron linear accelerator, which includes a fixed base 11 and a vacuum chamber 2. And, a height adjustment structure 13 is provided above the fixed base 11, a bottom plate 12 is provided on the height adjustment structure 13, the vacuum chamber 2 is installed on the bottom plate 12, and the height adjustment structure 13 is used to adjust the height and levelness of the bottom plate 12, which can be specific conventional technical means or disclosed technical means in this field and will not be elaborated herein.
[0021] The vacuum chamber 2 is provided with: A first port 21 and a second port 22, which are coaxially arranged and are respectively used for the laser beam to shoot out and bombard the cathode plate and the reflected electron beam bunch to be led out; wherein, the second port 22 is a CF50 flange to CF35 flange welding assembly for connecting with the main beam line.
[0022] Three third ports 23, which are provided and distributed on the left side, right side and upper side of the vacuum chamber 2, and the central axes of the three are coplanar and the coplanar plane is perpendicular to the central axes of the first port 21 and the second port 22.
[0023] An observation window assembly, which is arranged on the third port 23 for sealing the free end of the third port 23 and for light transmission, and in both of the two third ports 23 located on the left side and the right side, there is provided: A horizontal adjustment plate 3 is installed at the third port 23; A lateral position adjustment plate 4 is installed on the horizontal adjustment plate 3; An angular direction adjustment plate 5 is installed on the lateral position adjustment plate 4 and is arranged at an angle with the lateral position adjustment plate 4. Specifically, the angle between the side of the angular direction adjustment plate 5 close to the first port 21 and the lateral position adjustment plate 4 is an obtuse angle; and A lens 6, which is used to reflect the laser and the electron beam bunch, is installed on the side of the angular direction adjustment plate 5 close to the first port 21. There is a bunch channel 24 for the electron beam bunch to pass through between the two lenses 6 on the two relatively arranged third ports 23; the external laser is incident on the lens 6 from one of the third ports 23 provided with the lens 6, and a cut surface 61 is arranged at one end of the lens 6 close to the bunch channel 24. For the convenience of understanding this solution, taking the arrangement direction in the attached drawing as an example, it is assumed that the third port 23 on the left side is the incident port of the external laser, and the third ports 23 on the right side and the upper side are both observation ports. However, this description cannot be regarded as a limitation on the layout orientation of the three third ports 23 of this application.
[0024] Specifically, referring to Figure 2 and Figure 3 , the horizontal adjustment plate 3 is set as a cylindrical structure and fits on the inner wall of the third port 23. Its end has an end plate and is provided with a plurality of waist-shaped arc holes 31. The horizontal adjustment plate 3 is bolted and fixed on the third port 23 through bolts passing through the waist-shaped arc holes 31; a plurality of oblong holes 41 arranged along the axial direction of the horizontal adjustment plate 3 are provided on the lateral position adjustment plate 4. The lateral position adjustment plate 4 is bolted and fixed on the horizontal adjustment plate 3 through bolts passing through the oblong holes 41; the angular direction adjustment plate 5 is hinged to one end of the lateral position adjustment plate 4 extending into the inner cavity of the vacuum chamber 2, and is bolted and fixed on the lateral position adjustment plate 4 through bolts passing through their hinge parts.
[0025] Moreover, adjustment scales are arranged in the adjustment directions of the horizontal adjustment plate 3, the lateral position adjustment plate 4 and the angular direction adjustment plate 5 to facilitate improving the consistency of the two symmetrically arranged lenses 6 when adjusting the angle.
[0026] Thus, since the horizontal adjustment plate 3 is fixed to the third port 23 of the vacuum chamber 2, the direction can be adjusted within a small range. Specifically, the horizontal adjustment plate 3 is rotated so that the bolts thereon slide in the waist-shaped circular holes 31 and are locked, ensuring that the laser feeding point is exactly located at the height center of the cathode plate and compensating for the influence caused by the cumulative error of machining; moreover, since the horizontal adjustment plate 3 is cylindrical and fits with the inner wall of the third port 23, it can be ensured that the height center position of the horizontal adjustment plate 3 remains stable after being adjusted and fixed multiple times. By sliding the lateral position adjustment plate 4 on the horizontal adjustment plate 3 so that the bolts thereon slide in the long waist-shaped circular holes 41 and are locked, it can be ensured that the laser feeding point is exactly located at the horizontal center of the cathode plate, and it can be ensured that the horizontal position of the lateral position adjustment plate 4 remains consistent after being adjusted and installed multiple times. The angular direction adjustment plate 5 is adjusted according to the distance between the vacuum chamber 2 and the cathode plate. Specifically, the angular direction adjustment plate 5 is rotated on the lateral position adjustment plate 4 and the bolts are locked to change the included angle between the angular direction adjustment plate 5 and the lateral position adjustment plate 4, so that the laser can be fed into the lens 6 on the angular direction adjustment plate 5 and accurately bombard the center of the cathode plate after reflection.
[0027] Meanwhile, in view of the high vacuum requirement in the vacuum chamber 2, during the installation of the lens 6, the vacuum is not pumped. After the position of the lens 6 is determined, the entire mechanism starts to pump vacuum. It is required that the entire mechanism is stable and does not change during the vacuum pumping and operation processes; if the laser feeding point changes, the vacuum needs to be broken, readjusted, and then the vacuum is pumped again until the installation of the lens 6 meets the requirements.
[0028] And, with reference to Figure 2 and Figure 3 , the observation window assembly includes: A sealing flange 71, bolted and fixed to the end of the third port 23. The sealing flange 71 adopts a knife-edge flange and is sealed with a copper ring in the middle. This structure can achieve ultra-high vacuum under high-temperature conditions; An observation window pane 72, embedded in the sealing flange 71. It is made of quartz glass with a high light transmittance. Specifically, a counterbore for accommodating the observation window pane 72 is provided on the side of the sealing flange 71 facing away from the third port 23, and the observation window pane 72 is embedded in the counterbore; A pressing plate 73, bolted and fixed to the sealing flange 71, for pressing the observation window pane 72 onto the sealing flange 71; and A sealing plate 74, provided between the observation window pane 72 and the pressing plate 73 or the sealing flange 71. Both the pressing plate 73 and the sealing plate 74 are arranged in a ring shape with an inner diameter not less than the inner diameter of the third port 23.
[0029] Thus, when the external laser passes through the viewing window 72 on the left side and is fed into the vacuum chamber 2 through the third port 23 on the left side, it can be reflected by the lens 6 on the left side, pass through the first port 21, and bombard the cathode plate. The electron beam clusters released from the cathode plate then enter the vacuum chamber 2 through the first port 21, are emitted by the lens 6 on the right side, pass through the third port 23 and the viewing window 72 on the right side, and are observed by the human eye, enabling convenient visual observation and adjustment of the installation position of the lens 6. At the same time, the reflection paths of the laser beam and the electron beam clusters on the two lenses 6 can also be observed through the viewing window 72 on the upper side, facilitating the calibration of the verticality of the installation of the lens 6.
[0030] In another feasible embodiment, it is further set that, with reference to Figure 4 , a reticle 8 is provided on the viewing window 72 in the other third port 23 opposite to the third port 23 where the external laser enters. The main body of the reticle 8 is a cross reticle, and mil-scale lines are distributed on the cross reticle. When necessary, annular or arc lines can be further provided to perform accuracy verification on the landing point of the reflected electron beam clusters on the viewing window 72. Correspondingly, a reticle 8 can also be provided on the viewing window 72 on the left side, and the mirror image degree of the two lenses 6 can be verified by the landing point of the incident laser beam on the viewing window 72 on the left side and the landing point of the reflected electron beam clusters on the viewing window 72 on the right side.
[0031] In other feasible embodiments, it is further set that a polarizing film layer is provided on the viewing window 72 provided with the reticle 8. The polarizing film layer can eliminate stray light and reduce the damage to the human eye caused by the reflected electron beam clusters irradiating on the human eye, enabling the operator to observe the landing point of the reflected electron beam clusters for a long time within a certain period, and improving the verification efficiency of the installation accuracy of the lens 6.
[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended 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 described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. An electron linear accelerator laser feeding structure, characterized in that It includes a fixed base and a vacuum chamber, and the following are provided on the vacuum chamber: A first port and a second port, which are coaxially arranged and are respectively used for the laser beam to shoot out and bombard the cathode plate and for the electron beam bunch to be led out after reflection; Three third ports, which are distributed on the left side, right side and upper side of the vacuum chamber; An observation window assembly, which is arranged on the third port, and in each of the two third ports located on the left side and the right side, there is provided: A horizontal adjustment plate, which is installed on the third port; A lateral position adjustment plate, which is installed on the horizontal adjustment plate; An angular direction adjustment plate, which is installed on the lateral position adjustment plate and is arranged at an angle with the lateral position adjustment plate; and A lens, which is installed on the side of the angular direction adjustment plate close to the first port, and there is a bunch channel for the electron beam bunch to pass through between the two lenses on the two opposite third ports; the external laser is shot into the lens from one of the third ports provided with a lens.
2. The laser feeding structure of an electron linear accelerator according to claim 1, characterized in that, The horizontal adjustment plate is arranged as a cylindrical structure and fits on the inner wall of the third port, and a plurality of waist-shaped arc holes are opened at its end, and the horizontal adjustment plate is bolted and fixed on the third port through the bolts passing through the waist-shaped arc holes.
3. An electron linear accelerator laser feeding structure according to claim 2, characterized in that, A plurality of oblong holes are opened on the lateral position adjustment plate along the axial direction of the horizontal adjustment plate, and the lateral position adjustment plate is bolted and fixed on the horizontal adjustment plate through the bolts passing through the oblong holes.
4. An electron linear accelerator laser feeding structure according to claim 3, characterized in that, The angular direction adjustment plate is hinged to one end of the lateral position adjustment plate extending into the inner cavity of the vacuum chamber, and is bolted and fixed on the lateral position adjustment plate through the bolts passing through their hinge parts.
5. An electron linear accelerator laser feeding structure according to claim 1, characterized in that, One end of the lens close to the bunch channel is provided with a cut surface.
6. An electron linear accelerator laser feeding structure according to any one of claims 1-5, characterized in that, The observation window assembly includes: A sealing flange, which is bolted and fixed at the end of the third port; An observation window piece, which is embedded in the sealing flange; A pressing plate, which is bolted and fixed on the sealing flange and is used for pressing the observation window piece; and A sealing plate, which is arranged between the observation window piece and the pressing plate or the sealing flange.
7. An electron linear accelerator laser feeding structure according to claim 6, characterized in that, A graduation scale is arranged on the observation window piece in the other third port opposite to the third port into which the external laser is shot.
8. An electron linear accelerator laser feeding structure according to claim 7, characterized in that, A polarizing film layer is arranged on the observation window piece provided with the graduation scale.
9. An electron linear accelerator laser feeding structure according to claim 1, characterized in that, Adjustment scales are arranged in the adjustment directions of the horizontal adjustment plate, the lateral position adjustment plate and the angular direction adjustment plate.
10. The laser feeding structure of an electron linear accelerator according to claim 1, characterized in that, It further includes: A bottom plate, which is used for installing the vacuum chamber; A height adjustment structure, which is arranged between the bottom plate and the fixed base and is used for adjusting the height and levelness of the bottom plate.