A resonant cavity automatic field tuning system and method

Abstract

The application provides a resonant cavity automatic field adjusting system and method. The system realizes accurate, fast and automatic adjustment of the insertion depth of a tuner through response matrix and motor control, ensures that the electromagnetic field distribution meets the design requirements, and thus improves the performance and reliability of the equipment. Specifically, the insertion depth is calculated by subsection and the least square method to reduce the number of iterations and realize fast field adjustment; the tuner is driven by a stepping motor to realize automatic adjustment, which improves the adjustment accuracy and work efficiency compared with manual adjustment; a laser sensor is used to monitor the insertion depth of the tuner in real time and a closed loop control is adopted, which can effectively reduce external interference and make the adjustment more accurate.

Description

Technical Field

[0001] This invention relates to radio frequency quadrupole resonator field tuning technology, and more particularly to an automatic resonator field tuning system and method. Background Technology

[0002] The quadrupole radio frequency (RFQ) accelerator mainly consists of an octagonal resonant cavity and four electrodes. Each electrode tip is modulated by a sinusoidal curve with gradually increasing frequency along its longitudinal direction. The four electrodes generate a quadrupole field, with the electric field primarily distributed between the four tips, and the remaining area mainly consisting of a magnetic field. This structure allows for the focusing, beam convergence, and acceleration of particles. The purpose of field modulation is to maintain the uniformity of the electric field, thereby ensuring stable focusing and acceleration of particles, reducing beam divergence that could cause particles to strike the cavity walls and generate arcing, and improving the stability of the RFQ.

[0003] In electromagnetic field equipment such as radio frequency quadrupole (RFQ) systems, the uniformity and stability of the electromagnetic field directly affect the equipment's performance (such as particle acceleration efficiency and beam focusing effect). To achieve optimal performance, precise control of the electromagnetic field distribution is essential, and the tuner is a key component for achieving this goal. Traditional manual adjustment methods rely on the operator's experience and feel, resulting in low precision, slow efficiency, and poor consistency, making them unsuitable for the demands of modern high-precision equipment. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an automatic resonant cavity tuning system and method. This system, through response matrix and motor control, achieves precise, rapid, and automated adjustment of the tuner insertion depth, ensuring that the electromagnetic field distribution meets design requirements, thereby improving the performance and reliability of the equipment.

[0005] The specific technical solution of the present invention is as follows:

[0006] An automatic field tuning system for a resonant cavity includes a controller, a driver, a motor, a laser sensor, a tuner, and a power supply.

[0007] The controller receives insertion depth data of the radio frequency quadrupole tuner measured by the laser sensor, calculates the error between the current insertion depth and the target insertion depth, generates a control signal, and sends the control signal to the driver to control the motor; the motor adjusts the insertion depth of the tuner according to the control signal.

[0008] The cavity of the radio frequency quadrupole is divided into four quadrants, each quadrant has n tuners, and each tuner has m sampling points; the controller calculates the insertion depth by segmenting the response matrix of the field and using the least squares method.

[0009] The motor needs to be set with a threshold to prevent it from exceeding the physical range that the tuner can adjust.

[0010] The present invention also provides an automatic field adjustment method for a resonant cavity, characterized in that, based on the above system, it specifically includes the following steps:

[0011] First, the perturbation method is used, where a stepper motor drives a high-strength insulated wire, which in turn moves a small metal ball within a cavity to measure the initial field distribution within the cavity. Each tuner was moved individually, and the corresponding field E was repeatedly measured. Laser sensors were installed on the tuners to monitor the insertion depth of each tuner in real time. To calculate each element in the corresponding matrix. The change in insertion depth is used to obtain a 4m*4n response matrix M, which is then used to calculate its pseudo-inverse matrix using singular value decomposition. ;

[0012] Adjusting flatness: Setting the initial insertion depth Measure the current field distribution Calculate the mean of the current field distribution. and utilize Calculate the field flatness at this time. Next, check if the flatness requirement is met; if not, proceed. Calculate the error matrix, where e represents the field error matrix of the electric field; then through... Calculate the adjustment amount and output the new insertion depth. Next, closed-loop control is used to modify the tuner insertion depth. At this time, the controller reads the current insertion depth of the laser sensor. Next, calculate the control quantity. Then the controller according to The PWM signal is generated to drive the motor via a driver to adjust the tuner's insertion depth. Step Size is the distance the motor moves in each step. Then, the current field distribution is measured again, and the above process continues until the termination condition is met; otherwise, the system ends and the new insertion depth is output. ;

[0013] Adjusting for consistency: Measuring the current field distribution in all four quadrants. And calculate the mean. The termination condition is modified to ensure that the difference between the field distribution in each of the four quadrants and its average value meets the requirements, and the field error matrix is ​​updated. (i=1,2,3,4), the other steps are the same as the steps during the flatness adjustment.

[0014] The automatic resonant cavity tuning system of this invention can achieve precise, rapid, and automated adjustment of the tuner insertion depth, thereby improving tuning efficiency and accuracy. Specifically, it calculates the insertion depth by segmenting the response matrix and using the least squares method, reducing the number of iterations and achieving rapid tuning; it achieves fully automatic adjustment by driving the tuner with a stepper motor, which improves adjustment accuracy and work efficiency compared to manual adjustment; and it effectively reduces external interference and makes the adjustment more precise by using a laser sensor to monitor the tuner insertion depth in real time and employing closed-loop control. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the workflow of the system of the present invention.

[0016] Figure 2 This is a schematic diagram of the system architecture of the present invention. Detailed Implementation

[0017] To better understand the purpose, structure, and function of this invention, the following detailed description of an automatic field adjustment system for a resonant cavity, in conjunction with the accompanying drawings, is provided.

[0018] The system is divided into six modules, such as Figure 2 As shown, the components are the controller, driver, motor, laser sensor, tuner, and power supply. The following is a detailed description of the function of each module.

[0019] Controller: The controller mainly receives the tuner insertion depth data measured by the laser sensor, calculates the error between the current insertion depth and the target insertion depth, generates a control signal, sends the control signal to the driver, and controls the motor through the driver;

[0020] Driver: Receives control signals from the controller to drive the motor;

[0021] Electric motor: Adjusts the insertion depth of the tuner according to the control signal. The electric motor needs to be set with a threshold to prevent it from exceeding the physical range that the tuner can adjust.

[0022] Laser sensor: measures the insertion depth of the tuner in real time and transmits the data to the controller;

[0023] Tuners: The insertion depth of each tuner changes the distribution of the electromagnetic field within the RFQ cavity;

[0024] Power supply: Provides power to the entire system.

[0025] The method for automatically adjusting the field of the RFQ resonant cavity using this system is as follows: Figure 1 As shown, the details are as follows:

[0026] The RFQ cavity is divided into four quadrants, with n tuners in each quadrant. When measuring the field, m sampling points are selected. First, a perturbation method is used, where a stepper motor drives a high-strength insulated wire, which in turn moves a small metal ball within the cavity to measure the initial field distribution. Each tuner was moved individually, and the corresponding field E was repeatedly measured; laser sensors were installed on the tuners to monitor the insertion depth of each tuner in real time. To calculate each element in the corresponding matrix. The change in insertion depth yields a 4m*4n response matrix M. When measuring the response matrix, since the change in field due to the insertion depth of the tuner is only linear within a certain range, and its impact on the field differs depending on whether it is inserted or withdrawn at the cavity wall flush position, piecewise measurement is considered. Furthermore, since the response matrix M is usually not a square matrix, singular value decomposition is used to obtain its pseudo-inverse matrix. Field tuning mainly involves adjusting the flatness of a single quadrant and the consistency between the four quadrants. Singular value decomposition specifically decomposes M into... Where U and V are orthogonal matrices, Given a diagonal matrix containing singular values, its pseudo-inverse matrix is... ,in To be The matrix obtained by taking the reciprocal of the non-zero singular values ​​and transposing them.

[0027] When adjusting the flatness, first perform system initialization, i.e., set the initial insertion depth. Measure the current field distribution Calculate the mean of the current field distribution. and utilize Calculate the field flatness at this time. Next, check if the flatness meets the termination condition (generally, the flatness of the site should be within 3%). If it does not meet the requirement, then proceed. Calculate the error matrix, where e represents the field error matrix of the electric field; then through... Calculate the adjustment amount and output the new insertion depth. Next, closed-loop control is used to modify the tuner insertion depth. At this time, the controller reads the current insertion depth of the laser sensor. Next, calculate the control quantity. - Then the controller according to (Step Size is the distance the motor moves in each step) A PWM (Pulse Width Modulation) signal is generated to drive the motor via a driver to adjust the tuner's insertion depth. Then, the current field distribution is measured again, and the above process continues until the termination condition is met; otherwise, the system ends and a new insertion depth is output. .

[0028] When adjusting for consistency, the current field distribution in all four quadrants needs to be measured. And calculate the mean. The termination condition is modified to ensure that the difference between the field distribution in each of the four quadrants and its average value meets the requirements, and the field error matrix is ​​updated. (i=1,2,3,4), the other steps are the same as the steps during the flatness adjustment.

[0029] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. An automatic field adjustment system for a resonant cavity, characterized in that, Includes controller, driver, motor, laser sensor, tuner, and power supply; The controller receives insertion depth data of the radio frequency quadrupole tuner measured by the laser sensor, calculates the error between the current insertion depth and the target insertion depth, generates a control signal, and sends the control signal to the driver to control the motor; the motor adjusts the insertion depth of the tuner according to the control signal.

2. The automatic field adjustment system for a resonant cavity according to claim 1, characterized in that, The cavity of the radio frequency quadrupole is divided into four quadrants, each quadrant has n tuners, and each tuner has m sampling points; the controller calculates the insertion depth by segmenting the response matrix of the field and using the least squares method.

3. The automatic field adjustment system for a resonant cavity according to claim 2, characterized in that, The motor needs to be set with a threshold to prevent it from exceeding the physical range that the tuner can adjust.

4. An automatic field adjustment method for a resonant cavity, characterized in that, Based on the automatic field adjustment system for a resonant cavity as described in any one of claims 1-3, the system specifically includes the following steps: First, the perturbation method is used, where a stepper motor drives a high-strength insulated wire, which in turn moves a small metal ball within a cavity to measure the initial field distribution within the cavity. Each tuner was moved individually, and the corresponding field E was repeatedly measured. Laser sensors were installed on the tuners to monitor the insertion depth of each tuner in real time. To calculate each element in the corresponding matrix. To account for the change in insertion depth, the cavity of the RF quadrupole is divided into four quadrants, each with n tuners. Each tuner has m sampling points, resulting in a 4m*4n response matrix M. Then, singular value decomposition is used to obtain its pseudo-inverse matrix. ; Adjusting flatness: Setting the initial insertion depth Measure the current field distribution Calculate the mean of the current field distribution. And thus calculate the field flatness at this time. Next, check if the flatness meets the requirements; if not, proceed with the test. Calculate the error matrix, where e represents the field error matrix of the electric field; then through... Calculate the adjustment amount and output the new insertion depth. Next, closed-loop control is used to modify the tuner insertion depth. At this time, the controller reads the current insertion depth of the laser sensor. Next, calculate the control quantity. - The controller then generates a PWM signal based on the distance the motor moves in each step, which drives the motor via a driver to adjust the tuner's insertion depth. The current field distribution is then measured again, and the above process continues until the termination condition is met; otherwise, the system terminates and outputs the new insertion depth. ; Adjusting for consistency: Measure the current field distribution in each of the four quadrants and calculate the mean. The termination condition is modified to ensure that the difference between the field distribution in each of the four quadrants and its average value meets the requirements, and the field error matrix is ​​updated. (i=1,2,3,4, other steps are the same as the steps during flatness adjustment.)

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