Beam blocking device and method for accurately adjusting flow intensity

Abstract

The invention belongs to the technical field of accelerator equipment detection, and particularly relates to a beam blocking device and method for accurately adjusting the beam intensity, and the method comprises the steps: a motor unilaterally drives a beam blocking plate to move in the direction perpendicular to the beam intensity, the beam blocking plate firstly blocks the two sides of a beam spot and then gradually blocks the center of part of the beam spot, and the beam intensity is accurately adjusted; beam adjustment is carried out by blocking the edge position of the beam spot, most beam at the center of the beam spot can be reserved, and optimization of beam quality is guaranteed while the beam intensity is adjusted. The size parameter of the beam baffle is adjusted according to an accelerator light path design result so as to be matched with beam spots of different sizes, and beam adjustment is easily achieved; the driving motor with low moving precision is adopted, the beam baffle plate is unilaterally driven to realize beam adjustment, the structure of the device is simplified, and the cost is reduced; the beam current is adjusted by blocking the edge position of the beam spot, most beam current in the center of the beam spot can be reserved, and optimization of beam current quality can be guaranteed while the current intensity is adjusted.

Description

Technical Field

[0001] The invention belongs to the technical field of accelerator equipment detection, and in particular relates to a beam blocking device and method for accurately adjusting flow intensity. Background Art

[0002] The ion beam generated by the accelerator generally needs to be transmitted to the experimental terminal through beam transmission elements such as quadrupole lenses and single lenses for research. The ion beam intensity usually needs to be adjusted according to the experimental requirements. On the one hand, the adjustment of beam intensity can be achieved by changing the working parameters of the accelerator ion source, but changes in the working conditions of the ion source often lead to changes in the beam quality of the extracted beam, and the beam transmission elements need to be adjusted to ensure efficient transmission of the beam. On the other hand, a beam blocking device can be used to adjust the beam intensity by blocking the beam.

[0003] The beam blocking device has a generally rectangular shape. Common beam blocking devices are driven by double-sided motors or a single-sided motor with a direction-changing gear to complete beam blocking in the X and Y directions. They have a complex structure and are relatively expensive. When used for large beam current powers, a water cooling system needs to be added, making the structure of the beam blocking device more complex. At the same time, since the ion beam is close to a Gaussian distribution, as the beam blocking proceeds, the distance the beam blocking plate needs to move for the same amount of beam intensity change will become smaller, thereby placing higher requirements on the movement accuracy of the motor, further increasing the cost of the beam blocking device. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a beam blocking device and method for accurately adjusting the flux. The beam blocking device drives the beam blocking plate on one side through a motor. Since the ion beam is close to a Gaussian distribution, the beam blocking device will first block the two sides of the beam spot, and then gradually block part of the center of the beam spot, which can retain most of the beam current in the center of the beam spot, and achieve the optimization of the beam quality while adjusting the flux; compared with the rectangular beam blocking plate driven by the motor on one side / two sides, the beam blocking device requires a larger displacement distance to adjust the same beam current change, so a drive motor with lower movement accuracy can be selected to reduce costs.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows:

[0006] A method for accurately adjusting the flux intensity, wherein a motor drives a beam blocking plate unilaterally to move in a direction perpendicular to the beam direction, the beam blocking plate first blocks the two sides of the beam spot, and then gradually blocks part of the center of the beam spot. The beam is adjusted by blocking the edge of the beam spot, which can retain most of the beam in the center of the beam spot, thereby achieving optimization of the beam quality while adjusting the flux intensity.

[0007] Furthermore, as the beam blocking plate continues to move, the beam blocking plate can completely block the beam spot.

[0008] Furthermore, a beam blocking device for implementing the above method includes a beam blocking plate arranged perpendicular to the beam direction, the beam blocking plate is provided with an opening for the beam to pass through, and a motor drives the beam blocking plate to move in a direction perpendicular to the beam direction on one side, thereby blocking the beam as required to adjust the beam intensity.

[0009] Furthermore, the opening is symmetrical about the midplane of the beam blocking plate (ie, symmetrically arranged along a midaxis parallel to the movement direction of the beam blocking plate), and the distance from a side edge of the opening to the midplane gradually increases from inside to outside along the midplane.

[0010] Furthermore, the opening shape of the beam blocking plate is an isosceles triangle or an isosceles trapezoid.

[0011] Furthermore, the side edge of the beam blocking plate opening may be arc-shaped.

[0012] Furthermore, the outer peripheral shape of the beam blocking plate is rectangular.

[0013] Furthermore, the beam blocking plate has a width of A, a length of B, an opening angle of an isosceles triangle or an isosceles trapezoid of α, an opening length of an isosceles triangle or an isosceles trapezoid of d, and a distance from a vertex or an upper base to a width side length of an unopened side of L; the width A, length B, opening angle α, opening length d and distance L can all be adjusted according to the accelerator optical path design results to match the adjustment of beam spots of different sizes formed by different beam currents.

[0014] Furthermore, if it is necessary to completely shield the beam spot formed by the beam, the width A and the distance L from the vertex or upper bottom to the width side length of the unopened side are both greater than the beam spot diameter.

[0015] Furthermore, the direction in which the beam blocking plate moves under the unilateral driving of the motor is along the symmetry axis of the opening on the midplane toward the center of the beam spot.

[0016] Furthermore, the beam blocking plate is made of stainless steel or copper.

[0017] Furthermore, a water cooling pipe is arranged on the side of the beam blocking plate facing away from the beam flow to cool the beam blocking plate.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. The size parameters of the beam baffle can be adjusted according to the accelerator optical path design results to match the different sizes of beam spots formed by the ion source, and the beam current can be easily adjusted;

[0020] 2. Use a drive motor with low moving accuracy to drive the beam baffle on one side to achieve beam adjustment, which simplifies the structure of the device and reduces the cost;

[0021] 3. The beam quality at the center of the beam spot is generally better than that at the edge of the beam spot. The device adjusts the beam by blocking the edge of the beam spot, which can retain most of the beam at the center of the beam spot, and can optimize the beam quality while adjusting the beam intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of a beam blocking plate having an opening shape of an isosceles triangle;

[0023] Figure 2-1 is a structural schematic diagram of a beam blocking plate having an opening shape of an isosceles trapezoid;

[0024] Figure 2-2 The schematic diagram of the structure of the beam blocking plate with the side of the opening being in the shape of a parabola;

[0025] Figure 3 This is a comparison diagram of the beam spot shielding conditions at position 1 (left) and position 2 (right) during the operation of the beam blocking device;

[0026] Figure 4 A schematic diagram of the structure of a water cooling pipe arranged on the back of the beam baffle;

[0027] Figure 5 It is a schematic diagram of the structure of the water-cooled beam blocking device. DETAILED DESCRIPTION

[0028] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0029] The present invention designs a method for accurately adjusting the flux intensity. A motor drives a beam blocking plate unilaterally to move in a direction perpendicular to the beam. The beam blocking plate first blocks the two sides of the beam spot, and then gradually blocks part of the center of the beam spot. The beam is adjusted by blocking the edge of the beam spot, which can retain most of the beam in the center of the beam spot, thereby achieving optimization of the beam quality while adjusting the flux intensity.

[0030] The present invention designs a beam blocking device for accurately adjusting the beam intensity, comprising a beam blocking plate arranged perpendicular to the beam direction, the beam blocking plate is provided with an opening for the beam to pass through, a motor drives the beam blocking plate unilaterally to move in a direction perpendicular to the beam direction, and blocks the beam as required to adjust the beam intensity.

[0031] The specific technical solutions are as follows:

[0032] Method for precisely adjusting the flux intensity: The motor drives the beam baffle plate to move perpendicular to the beam direction on one side. The beam baffle plate first blocks the two sides of the beam spot, and then gradually blocks part of the center of the beam spot. By blocking the edge of the beam spot for beam adjustment, the beam in the center of most of the beam spot can be retained, so that the beam quality can be optimized while adjusting the flux intensity. As the beam baffle plate continues to move, it can completely block the beam spot.

[0033] The peripheral shape of the beam blocking plate is a geometric figure symmetrical about the midplane of the beam blocking plate, and the peripheral shape of the beam blocking plate can be a rectangle. The opening on the beam blocking plate is symmetrical about the midplane of the beam blocking plate (i.e., symmetrically arranged along the central axis parallel to the movement direction of the beam blocking plate), and the distance from one side of the opening to the midplane gradually increases along the midplane from the inside to the outside. The shape of the opening on the beam blocking plate can be an isosceles triangle, an isosceles trapezoid, or a geometric figure with an arc on the side of the opening, or other geometric shapes that can adjust the beam by blocking the edge position of the beam spot.

[0034] The beam blocking plate structure of the present invention has an opening shape of an isosceles triangle. Figure 1 As shown. The plate surface of the beam baffle is perpendicular to the direction of the ion beam generated by the accelerator. The outer peripheral shape of the beam baffle is a rectangle, and the opening shape is an isosceles triangle. The width of the beam baffle is A, the length is B, the distance from the vertex to the width side of the unopened side is L, the isosceles triangle opening angle is α, and the isosceles triangle opening length is d. The width A, length B, the isosceles triangle opening angle α, the isosceles triangle opening length d and the distance L from the vertex to the width side of the unopened side can all be adjusted according to the accelerator optical path design results to match the adjustment of different sizes of beam spots formed by different beams. The beam spot formed by the ion beam generated by the accelerator is approximately circular. If the beam spot needs to be completely blocked, the width A and the distance L from the vertex to the width side of the unopened side are both greater than the beam spot diameter.

[0035] The beam blocking plate structure of the present invention has an isosceles trapezoidal opening shape. Figure 2-1 As shown. The plate surface of the beam baffle is perpendicular to the direction of the ion beam generated by the accelerator. The outer peripheral shape of the beam baffle is a rectangle, and the opening shape is an isosceles trapezoid. The width of the beam baffle is A, the length is B, the distance from the upper base to the width side of the unopened side is L, the opening angle of the isosceles trapezoid is α, and the opening length of the isosceles trapezoid is d. The width A, length B, opening angle α, opening length d, and the distance L from the upper base to the width side of the unopened side can all be adjusted according to the accelerator optical path design results to match the adjustment of different sizes of beam spots formed by different beams. The beam spot formed by the ion beam generated by the accelerator is approximately circular. If the beam spot needs to be completely blocked, the width A and the distance L from the upper base to the width side of the unopened side are both greater than the beam spot diameter.

[0036] The structure of the beam blocking plate with an arc-shaped side opening of the present invention is as follows Figure 2-2 As shown. The surface of the beam blocking plate is perpendicular to the direction of the ion beam generated by the accelerator. The outer periphery of the beam blocking plate is rectangular, and the side of the opening is arc-shaped.

[0037] The beam blocking plate is made of stainless steel or copper, etc. The outer shape of the beam blocking plate and the specific shape and geometric dimensions of the opening on the beam blocking plate need to be determined according to the size of the beam spot, the beam density distribution and the adjustment accuracy of the beam intensity.

[0038] The present invention discloses a beam blocking device for precisely adjusting the current intensity. The beam blocking plate is driven by a motor on one side to move in a direction perpendicular to the ion beam generated by the accelerator, and along the symmetry axis of the opening on the midplane toward the center of the circular beam spot. The beam blocking plate is driven by a motor to precisely control the position of the beam blocking plate, and the beam spot formed by the ion beam generated by the accelerator can be shielded as required to adjust the beam intensity.

[0039] The beam blocking device for accurately adjusting the flow intensity of the present invention has a working process as follows: Figure 3 As shown. When the current intensity needs to be adjusted, the motor drives the beam blocking plate through the coupling, moves in a direction perpendicular to the ion beam generated by the accelerator, and moves along the symmetry axis of the opening on the midplane toward the center of the circular beam spot. At position 1, a small part of the edge beam is blocked by the beam blocking plate; then the beam blocking plate is moved to position 2, and the beam blocking plate blocks most of the edge beam to achieve the purpose of adjusting the current intensity. Since the beam spot is generally Gaussian distributed, the beam density at the center of the beam spot is greater than the beam density at the edge. The beam blocking device is used to block the edge of the beam spot for beam adjustment. On the one hand, since the beam density at the edge is smaller, the distance that the beam blocking device needs to move is larger than that at the center, so a drive motor with lower moving accuracy can be selected; on the other hand, since the beam quality at the center of the beam spot is generally better than the beam quality at the edge of the beam spot, the beam blocking device can retain most of the beam at the center when it is working, which can achieve the optimization of beam quality while adjusting the current intensity. If it is necessary to completely block the beam, the beam blocking device continues to move to completely block the beam spot.

[0040] For high beam power, it is necessary to set a water cooling pipe on the side of the beam blocking plate facing away from the beam to cool the beam blocking plate. The structure of the water cooling pipe set on the back of the beam blocking plate is as follows: Figure 4 The water cooling pipe is fixed to the back of the beam baffle plate by welding, and is closely fitted to the beam baffle plate. Cooling water flows through the pipe to cool the beam baffle plate.

[0041] Take the water-cooled beam blocking device as an example:

[0042] The specific structure of the water-cooled beam blocking device of this embodiment is as follows: Figure 5As shown, the outer shape of the beam blocking plate is a rectangle, and the opening shape is an isosceles triangle. According to the system optical path design results, the beam spot diameter formed by the ion beam generated by the accelerator at the beam blocking device is about 10mm, the width A of the beam blocking plate is 40mm, the length B is 55mm, the opening angle α is 90°, the opening length d is 20mm, and the distance L from the vertex to the width and side length of the unopened side is 45mm; the beam blocking plate is made of copper material, and is equipped with a water cooling pipe on the back, and cooling water is passed inside to cool the beam blocking plate.

[0043] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for accurately adjusting flow intensity, characterized in that: The motor drives the beam baffle plate unilaterally to move in a direction perpendicular to the beam. The beam baffle plate first blocks the two sides of the beam spot, and then gradually blocks part of the center of the beam spot. The beam is adjusted by blocking the edge of the beam spot, which can retain most of the beam in the center of the beam spot, thereby achieving the optimization of the beam quality while adjusting the beam intensity.

2. A method for accurately adjusting flow intensity according to claim 1, characterized in that: As the beam blocking plate continues to move, the beam blocking plate can completely block the beam spot.

3. A beam blocking device for implementing the method according to any one of claims 1 to 2, characterized in that: It comprises a beam blocking plate arranged perpendicular to the beam direction, the beam blocking plate is provided with an opening for the beam to pass through, a motor drives the beam blocking plate to move perpendicular to the beam direction on one side, and blocks the beam as required to adjust the beam intensity.

4. A beam blocking device for accurately adjusting flow intensity as claimed in claim 3, characterized in that: The opening is symmetrical about the middle plane of the beam blocking plate, and the distance from a side edge of the opening to the middle plane gradually increases from the inside to the outside along the middle plane.

5. A beam blocking device for accurately adjusting flow intensity as claimed in claim 4, characterized in that: The opening shape of the beam blocking plate is an isosceles triangle or an isosceles trapezoid.

6. A beam blocking device for accurately adjusting flow intensity as claimed in claim 4 or 5, characterized in that: The side edge of the beam blocking plate opening may be arc-shaped.

7. A beam blocking device for accurately adjusting flow intensity as claimed in claim 5, characterized in that: The outer peripheral shape of the beam blocking plate is rectangular.

8. A beam blocking device for accurately adjusting flow intensity as claimed in claim 7, characterized in that: The beam blocking plate has a width of A, a length of B, an opening angle of an isosceles triangle or an isosceles trapezoid of α, an opening length of an isosceles triangle or an isosceles trapezoid of d, and a distance from a vertex or an upper base to a width side length of an unopened side of L; the width A, length B, opening angle α, opening length d and distance L can all be adjusted according to the accelerator optical path design results to match the adjustment of beam spots of different sizes formed by different beam currents.

9. A beam blocking device for accurately adjusting flow intensity as claimed in claim 8, characterized in that: If it is necessary to completely block the beam spot formed by the beam, the width A and the distance L from the vertex or upper bottom to the width side length of the unopened side are both greater than the beam spot diameter.

10. A beam blocking device for accurately adjusting flow intensity as claimed in claim 4, characterized in that: The direction in which the beam blocking plate moves under the unilateral driving of the motor is along the symmetry axis of the opening on the midplane toward the center of the beam spot.

11. A beam blocking device for accurately adjusting flow intensity as claimed in claim 3, characterized in that: The beam blocking plate is made of stainless steel or copper.

12. A beam blocking device for accurately adjusting flow intensity as claimed in claim 3, characterized in that: A water cooling pipe is arranged on the side of the beam blocking plate facing away from the beam flow to cool the beam blocking plate.

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