A tuning method for high-energy accelerator four-cavity

Abstract

The application discloses a tuning method for a four-cavity high-energy accelerator, and comprises the following steps: arranging a tuning motor and an electronic ruler on the outer part of each cavity of the four-cavity resonant cavity, setting the initial positions of the four tuning motors and the initial positions of the electronic rulers respectively equipped on the four tuning motors; moving the tuning motor M1, and using the tuning motor M1 to complete the searching of the resonant point in the S1 state of the low-level control system, the amplitude climbing in the S2 state, and the amplitude stable closed loop in the S3 state; when reaching the thermal balance, entering the voltage deviation compensation stage: taking the capacitance variation as a step, alternately adjusting the capacitance variations of the tuning motors M1, M2, M3 and M4, so that the voltage deviations among the tuning motors M1, M2, M3 and M4 are close to 0; the method of "step" + "electronic ruler" + "contrast table" + "fitting curve" + "alternately adjusting" is adopted, and the problem of deviation compensation confusion caused by signal delay and mechanical transmission error during multi-motor tuning is solved.

Description

Technical Field

[0001] This invention belongs to the technical field of high-frequency systems for cyclotron accelerators, and particularly relates to a tuning method for a four-cavity high-energy accelerator. Background Technology

[0002] The high-frequency system is a crucial component of a cyclotron, and its stability and reliability play a key role in the cyclotron's performance. The high-frequency system of a cyclotron mainly consists of three parts: a high-frequency power source, a resonant cavity, and a low-level system. The high-frequency power source provides energy for particle motion; the resonant cavity provides a stable high-frequency electric field for charged particles through resonance; and the low-level system controls and corrects parameters such as the amplitude and phase of the accelerating field to ensure stable cavity operation. The four cavities mentioned in this paper are directly connected at the Dee board heads of each cavity, thus they can be considered as a single high-frequency system, controllable by one transmitter and one low-level system.

[0003] During high-power operation, the resonant cavity generates significant heat. Even with water cooling, temperature changes still cause deformation of the cavity. This deformation alters the cavity's equivalent capacitance, leading to a change in its resonant frequency. Therefore, a tuning device is needed to match the incident power frequency with the cavity's resonant frequency. This tuning device consists of a tuning capacitor plate positioned outside the cavity. Controlled by a low-level control system, the distance between the tuning capacitor plate and the cavity is altered, thereby changing the cavity's equivalent capacitance and achieving frequency tuning.

[0004] One of the difficulties in tuning the frequency of a four-cavity resonant cavity lies in: Figure 3a , 3b As shown, when there is only one tuning capacitor (meaning only one of the four cavities has a tuning capacitor plate on its outer side, driven by a tuning motor), the beam loss of the four-cavity resonant cavity increases significantly. This is because four-cavity resonant cavities are generally used in high-energy cyclotron accelerators. High-energy cyclotron accelerators have a high beam rotation count. With only one tuning capacitor, CST software simulations show that the accelerating gap voltage of the cavity with the tuning capacitor is about 8% higher than the other three cavities. When the accelerating gap voltage of the cavity with the tuning capacitor is 8% higher than the other three cavities per rotation, it will inevitably lead to a decrease in beam extraction efficiency. The higher the beam energy, the more rotations the particles make in the accelerator, and the greater the increase in beam loss. From an accelerator physics perspective, this can be described as follows: when the two high-frequency accelerating gaps in the accelerator are larger than the other six accelerating gaps, the beam will undergo misaligned acceleration during acceleration. Precession occurs during beam acceleration, increasing the cyclic emittance of the beam and ultimately leading to a larger beam envelope. When the beam passes through the dangerous resonance region of the magnetic field, the beam oscillation amplitude increases, causing beam loss.

[0005] The second difficulty of the frequency tuning of the four-cavity resonant cavity lies in that when multiple tuning capacitors (one tuning motor and tuning capacitor plate are arranged for each cavity of the four-cavity) are used, it is difficult to ensure the consistency of starting, stopping and turning of multiple tuning motors due to mechanical transmission error and signal delay error, and multiple motors simultaneously moving may cause a very chaotic situation due to mechanical transmission error and signal delay error. SUMMARY

[0006] The present application aims at the problems existing in the prior art, and proposes a tuning method for a four-cavity of a high-energy accelerator. The first purpose is to solve the problem that when there is only one capacitor, the cavity with the capacitor has an acceleration gap voltage higher than that of the other three cavities by about 8%, which will certainly lead to the decrease of the efficiency of the beam, and the higher the beam energy, the more the number of revolutions of the particles in the accelerator, and the more the increase of the beam loss. The second purpose is to solve the problem that when multiple tuning capacitors are used, it is difficult to ensure the consistency of starting, stopping and turning due to mechanical transmission error and signal delay error, and multiple motors simultaneously moving leads to a very chaotic situation due to mechanical transmission error and signal delay error.

[0007] The present application adopts the following technical solutions to solve the technical problems:

[0008] The application discloses a tuning method for a four-cavity high-energy accelerator, and the method is based on a four-cavity resonant cavity tuning device, wherein the four-cavity resonant cavity tuning device comprises a transmitter, a four-cavity resonant cavity, a low-level control system, a directional coupler and a host computer; the head of each cavity of the four-cavity resonant cavity is connected by a bridge, and each cavity is externally provided with a tuning motor M1, M2, M3 or M4; each tuning motor is further provided with an electronic ruler for feeding back the position of the motor; the transmitter is used for amplifying the signal from the low-level control system and feeding the signal into the four-cavity resonant cavity through a transmission line; the input end of the transmitter is connected with the low-level control system, the output end of the transmitter is connected with the cavity 1, and the cavity 2, the cavity 3 and the cavity 4 are connected with the cavity 1 by a bridge; the four-cavity resonant cavity provides a stable high-frequency electric field for charged particles through resonance; the input end of the four-cavity resonant cavity is connected with the transmitter, wherein the cavity 2, the cavity 3 and the cavity 4 are connected with the transmitter through the cavity 1; the low-level control system controls the resonant capacitance of the cavity 1, the cavity 2, the cavity 3 and the cavity 4 of the resonant cavity through the motors M1, M2, M3 and M4 respectively, acquires the internal power signals of the cavity 1, the cavity 2, the cavity 3 and the cavity 4 of the four-cavity resonant cavity, acquires the incident power signals from the directional coupler, and controls the tuning motor to tune the frequency of the resonant cavity through phase discrimination of the two signals; the directional coupler is arranged on the transmission line between the transmitter and the resonant cavity, acquires the incident power signals from the transmitter, and samples the signals as one of the signals of each tuning ring; the host computer is bidirectionally connected with the low-level control system; the host computer communicates with the low-level control system, switches the high-frequency exercise mode S1-S3 mode and the beam output mode S1-S5 mode, and controls the tuning of the four tuning rings through the current positions of the four tuning motors, and the tuning method comprises the following steps.

[0009] Step one, an electronic ruler is arranged on the outside of each cavity of the four-cavity resonant cavity, and the electronic ruler is used for feeding back the current position of the tuning motor;

[0010] Step two, the initial positions of the tuning motors M1, M2, M3 and M4 and the initial positions of the electronic rulers matched with the tuning motors are set, and in order to reduce the movement distance of the motors and the change of the resonant points of the motors caused by cavity maintenance, the four motors are homed to the middle positions of the electronic rulers each time;

[0011] Step three, the tuning motor M1 is moved, and the tuning motor M1 is used to complete the search of the resonant point in the S1 state of the low-level control system, the amplitude climbing in the S2 state and the amplitude stable closed loop in the S3 state; the tuning motors M2, M3 and M4 do not move during this period;

[0012] Step four, the low-level control system keeps the S3 state for a period of time to reach thermal equilibrium, and the judgment condition is time, which is set according to the debugging experience;

[0013] Step five, entering S4 voltage deviation compensation stage: adjusting the capacitance variation of tuning motors M1, M2, M3 and M4 alternately, so that the voltage deviation between the tuning motors M1, M2, M3 and M4 approaches 0;

[0014] The setting method of the capacitance variation of step five is as follows:

[0015] 1) Establish a table of capacitance values and electronic ruler positions and fit it into a mathematical formula curve;

[0016] 2) Capacitance variation = capacitance value at current position of tuning motor to be moved - (sum of capacitance values at positions of tuning motors to be moved in current stage) ÷ number of motors to be moved in current stage; the current stage includes S4-1 stage, S4-2 stage and S4-3 stage, and 2, 3 and 4 motors are moved respectively;

[0017] 3) Divide the capacitance variation of the current tuning motor into several parts equally, and obtain the moving distance of the electronic ruler corresponding to each part of the capacitance variation through the mathematical formula fitting curve;

[0018] 4) Move the tuning motor according to the moving distance of the electronic ruler corresponding to each part of the capacitance variation.

[0019] Further, the initial positions of the four tuning motor electronic rulers are the same, and the lengths are the same, that is, the distances of the four electronic rulers from the resonant cavity are the same.

[0020] Further, the adjustment of the capacitance variation of the tuning motors M1, M2, M3 and M4 in step five so that the voltage deviation between the tuning motors M1, M2, M3 and M4 approaches 0 is as follows:

[0021] (1) Move the tuning motors M1 and M2, and only the tuning motor M1 is in working state before, and both the tuning motor M1 and the tuning motor M2 are in working state currently;

[0022] A, the capacitance variation of the tuning motor M1 = capacitance value at the position of the tuning motor M1 - (sum of capacitance values at the positions of the tuning motor M1 and the tuning motor M2) ÷ 2;

[0023] B, the capacitance variation of the tuning motor M2 = capacitance value at the position of the tuning motor M2 - (sum of capacitance values at the positions of the tuning motor M1 and the tuning motor M2) ÷ 2;

[0024] C, divide the capacitance variations of the tuning motor M1 and the tuning motor M2 into 100 parts equally respectively, and obtain the moving distance of the electronic ruler corresponding to each part of the capacitance variation through the fitting curve calculation;

[0025] D. Move the tuning motor M1 and the tuning motor M2 according to the moving distance of the electronic ruler corresponding to each part of the capacitance change amount;

[0026] (2) Move the tuning motor M1, M2, M3. Previously, only the tuning motor M1 and the tuning motor M2 were in working condition, and currently the tuning motor M1, the tuning motor M2, and the tuning motor M3 are all in working condition;

[0027] A. After the tuning motor M1 and the tuning motor M2 reach the desired capacitance change amount, the tuning motor M1 and the tuning motor M2 are regarded as a whole or as a tuning motor group 12 ; the tuning motor group 12 is regarded as a whole, and the capacitance change amount of each tuning motor in the tuning motor group

[0028] B. The tuning motor group 12 ; the tuning motor group 12 is regarded as a whole, and the capacitance change amount of each tuning motor in the tuning motor group

[0029] C. The capacitance change amount of the tuning motor M3 = the capacitance value at the tuning motor M3 position - (the capacitance value at the tuning motor M1 position + the capacitance value at the tuning motor M2 position + the capacitance value at the tuning motor M3 position) ÷ 3;

[0030] D. Divide the capacitance change amount of the tuning motor group 12 and the capacitance change amount of the tuning motor M3 into 100 parts respectively, and obtain the moving distance of the electronic ruler corresponding to each part of the capacitance change amount by fitting a curve through a mathematical formula;

[0031] E. Move each tuning motor of the tuning motor group 12 and the tuning motor M3 according to the moving distance of the electronic ruler corresponding to each part of the capacitance change amount;

[0032] (4) Move the tuning motor M1, M2, M3, M4. Previously, only the tuning motor M1, the tuning motor M2, and the tuning motor M3 were in working condition, and currently the tuning motor M1, the tuning motor M2, the tuning motor M3, and the tuning motor M4 are all in working condition;

[0033] A. After the tuning motor M1, the tuning motor M2, and the tuning motor M3 reach the desired capacitance change amount, the tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group 123 ; the tuning motor group 123 is regarded as a whole, and the capacitance change amount of each tuning motor in the tuning motor group

[0034] B. The tuning motor group 123The capacitance variation amount of the tuning motor group 123 The capacitance variation amount of any tuning motor in the tuning motor group = (the capacitance value of the tuning motor M1 position + the capacitance value of the tuning motor M2 position + the capacitance value of the tuning motor M3 position + the capacitance value of the tuning motor M4 position) ÷ 4 123 The capacitance variation amount of each tuning motor in the tuning motor group is the same;

[0035] C. The capacitance variation amount of the tuning motor M4 = (the capacitance value of the tuning motor M1 position + the capacitance value of the tuning motor M2 position + the capacitance value of the tuning motor M3 position + the capacitance value of the tuning motor M4 position) ÷ 4

[0036] D. The tuning motor group 123 The capacitance variation amount and the capacitance variation amount of the tuning motor M4 are evenly divided into 100 parts, and the moving distance of the electronic ruler corresponding to each part of the capacitance variation amount is obtained by fitting a curve through a mathematical formula;

[0037] E. According to the moving distance of the electronic ruler corresponding to each part of the capacitance variation amount, each tuning motor in the tuning motor group 123 and the tuning motor M4 are moved respectively.

[0038] Advantages and effects of the present application

[0039] 1. The present application adopts the method of "step" + "electronic ruler": It makes up for the error from mechanical transmission or the error from signal delay (the step in this embodiment is the capacitance variation amount), and adjusts the tuning according to the "step". The focus is on the "step" regardless of whether the error of mechanical transmission or the error of signal delay occurs in the middle. Even if there is an error, when the "step" is met, the error has been overcome. The "electronic ruler" is a means to ensure that the "step" is executed in place. When the capacitance variation amount is used as the step and the capacitance variation amount of the tuning motor is adjusted alternately, there will still be errors of mechanical transmission and signal delay. Since the electronic ruler is adopted, we focus on the moment when the motor reaches the target point on the electronic ruler. If an error occurs, the moment when the motor reaches the target point on the electronic ruler may be a little earlier or later, but it will eventually reach the target point. Since it is an alternating operation, when the previous target point is reached, the next target point is continued. In this way, the problem of inconsistency in starting, stopping and turning due to mechanical transmission error and signal delay error when multiple tuning capacitors are used is solved. The simultaneous movement of multiple motors leads to a very chaotic situation due to mechanical transmission error and signal delay error.

[0040] 2, The application adopts the method of "look-up table" + "fitted curve", solves the problem of nonlinearity between the capacitance change and the motor moving distance, the look-up table is used to compare the motor position and the capacitance value, although the motor position and the capacitance value are in nonlinear relationship, the horizontal and vertical coordinates of each point on the nonlinear curve are fixed, the method of fitting curve through mathematical formula avoids the nonlinear relationship between the motor position and the capacitance value, and finally realizes the tuning motor position, the method of "look-up table" + "fitted curve" solves the problem of alternating adjustment of the capacitance change by "step length". BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 It is a tuning device for four cavities of a high-energy accelerator;

[0042] Figure 2 It is an electronic ruler schematic diagram;

[0043] Figure 3a It is a schematic diagram of four cavities with only one tuning capacitor in the prior art;

[0044] Figure 3b It is a schematic diagram of two acceleration slit voltages of one cavity with a tuning capacitor being about 8% higher than six acceleration slit voltages of the other three cavities in the prior art;

[0045] Figure 4 It is an effect diagram of the voltage deviation of eight acceleration slit voltages of four cavities being close to 0 after voltage deviation compensation;

[0046] Figure 5 It is a tuning method flow chart for four cavities of a high-energy accelerator;

[0047] Figure 6 It is a schematic diagram of the approximate relationship between the tuning capacitor distance from the resonant cavity and the tuning capacitor change. DETAILED DESCRIPTION

[0048] Design principle of the application

[0049] The innovation of this invention lies in its use of a "step size + reference table + fitting curve + electronic ruler + alternating adjustment" method to solve the problem of voltage deviation compensation in multi-cavity systems. The "step size" refers to the capacitance change. The significance of the "step size" and the "electronic ruler" is that when used together, they can compensate for errors caused by mechanical transmission or signal delay. For example, if a mechanical transmission error causes the tuning motor to not reach its designated position within a specified time, the motor position fed back by the electronic ruler will also be out of position. Once the motor position fed back by the electronic ruler reaches the predetermined position, the error caused by the mechanical transmission has been compensated. The significance of the "reference table" and the "fitting curve" is that they solve the problem of the non-linear relationship between the moving distance of the tuning motor and the capacitance change. The relationship between the tuning capacitance value and the distance between the capacitor plates can be viewed as a non-ideal parallel-plate capacitor; mathematically, the closer the capacitor plate is to the cavity, the faster the capacitance increases. This trend can be approximated by a similar curve. Figure 6 The curve, assuming the position of the electron ruler corresponds to 0-100 from closest to farthest from the cavity, from... Figure 6 It can be seen that a movement of 10 units in the range of the horizontal axis from 10 to 20 has a greater impact on the capacitor than a movement of 30 units in the range of the horizontal axis from 50 to 80. This means that the rate of change of capacitance is not uniform at different motor positions. Therefore, a "motor position and capacitance value" reference table is established, and a mathematical curve is fitted. The significance of "alternating adjustment" lies in ensuring the accuracy of the calculation result at each step through sequential operations in time. Only when the capacitance change in the previous step is correct can the capacitance change in the next step be guaranteed to be correct, because the previous calculation is the basis for the subsequent calculation. This solves the problem of inconsistent synchronization caused by errors when four tuned motors operate simultaneously.

[0050] In summary, the five aspects of step size, reference table, fitting curve, electronic ruler, and alternating adjustment support each other and are indispensable. When they are organically combined, the voltage deviation of the multi-cavity is close to 0.

[0051] Based on the above-mentioned principles, this invention designs a tuning method for a four-cavity high-energy accelerator. This method is based on a four-cavity resonant cavity tuning device, such as... Figure 1 , 2As shown, the four-cavity tuning device includes a transmitter, a four-cavity resonant cavity, a low-level control system, a directional coupler and a host computer; the head of the cavity 1, the cavity 2, the cavity 3 and the cavity 4 of the four-cavity resonant cavity is connected by a bridge, and each cavity is externally provided with a tuning motor M1, M2, M3 and M4, and each tuning motor is further provided with an electronic ruler for feeding back the position of the motor; the transmitter is used for amplifying the signal from the low-level control system and feeding into the four-cavity resonant cavity through the transmission line; the input end is connected with the low-level control system, the output end is connected with the cavity 1, and the cavity 2, the cavity 3 and the cavity 4 are connected by a bridge; the four-cavity resonant cavity provides a stable high-frequency electric field for charged particles through resonance; the input end is connected with the transmitter, wherein the cavity 2, the cavity 3 and the cavity 4 are connected with the transmitter through the cavity 1; the low-level control system controls the resonant capacitance of the cavity 1, the cavity 2, the cavity 3 and the cavity 4 of the resonant cavity through the motors M1, M2, M3 and M4 respectively, and obtains the internal power signal from the cavity 1, the cavity 2, the cavity 3 and the cavity 4 of the four-cavity resonant cavity, and obtains the incident power signal from the directional coupler, the two signals are phase detected and control the tuning motor to tune the frequency of the resonant cavity; the directional coupler is arranged on the transmission line between the transmitter and the resonant cavity, which obtains the incident power signal from the transmitter and samples as one of the signals of each tuning ring; the host computer is bidirectionally connected with the low-level control system; the host computer switches the high-frequency exercise mode S1-S3 mode and the beam mode S1-S5 mode by communicating with the low-level control system, and the host computer controls the tuning of the four tuning rings through the current positions of the four tuning motors, and the characteristic is that the tuning method comprises the following steps, such as Figure 5 As shown:

[0052] Step one, a tuning motor and an electronic ruler are arranged outside each cavity of the four-cavity resonant cavity, and the electronic ruler is used to feed back the current position of the tuning motor;

[0053] Step two, set the initial position of the tuning motors M1, M2, M3 and M4 and the initial position of the electronic rulers equipped with them respectively, in order to reduce the movement distance of the motor and the change of the resonant point of the motor caused by the maintenance of the cavity, each time the four motors are homed to the position in the middle of the electronic ruler;

[0054] Step three, move the tuning motor M1, use the tuning motor M1 to complete the search of the resonant point in the S1 state of the low-level control system, the amplitude climbing in the S2 state, and the amplitude stable closed loop in the S3 state; the tuning motors M2, M3 and M4 do not act during this period;

[0055] Step four, the low-level control system keeps in the S3 state for a period of time to reach thermal equilibrium, and the judgment condition is time, which is set by the debugging experience in daily life;

[0056] Step five, entering S4 voltage deviation compensation stage: adjusting the capacitance variation of tuning motors M1, M2, M3 and M4 alternately as a step, so as to make the voltage deviation between the tuning motors M1, M2, M3 and M4 close to 0;

[0057] Supplementary Note 1

[0058] The effect of the voltage deviation close to 0 is shown in the figure Figure 4 The eight curves of the eight accelerating gaps of the four resonant cavities almost fit together, which proves that the voltage deviation between the improved tuning motors M1, M2, M3 and M4 is close to 0.

[0059] The setting method of the capacitance variation of step five is as follows:

[0060] 1) Establish a table of capacitance values and electronic ruler positions and fit it into a mathematical formula curve;

[0061] 2) Capacitance variation = capacitance value at current position of tuning motor to be moved - (sum of capacitance values at positions of tuning motors to be moved in current stage) ÷ number of motors to be moved in current stage; the current stage includes S4-1 stage, S4-2 stage and S4-3 stage, and 2, 3 and 4 motors are moved respectively;

[0062] 3) Divide the capacitance variation of the current tuning motor into several parts equally, and obtain the moving distance of the electronic ruler corresponding to each part of the capacitance variation through the mathematical formula fitting curve;

[0063] 4) Move the tuning motor according to the moving distance of the electronic ruler corresponding to each part of the capacitance variation.

[0064] Further, the initial positions of the four tuning motor electronic rulers are the same, and the lengths are the same, and the same initial position means that the distances of the four electronic rulers from the resonant cavity are the same.

[0065] Further, the adjustment of the capacitance variation of the tuning motors M1, M2, M3 and M4 in step five so as to make the voltage deviation between the tuning motors M1, M2, M3 and M4 close to 0 is as follows:

[0066] (1) Move the tuning motors M1 and M2, and only the tuning motor M1 is in working state before, and both the tuning motor M1 and the tuning motor M2 are in working state currently;

[0067] A. Capacitance variation of tuning motor M1 = capacitance value at position of tuning motor M1 - (sum of capacitance values at positions of tuning motor M1 and tuning motor M2) ÷ 2;

[0068] B. The change in capacitance of tuned motor M2 = capacitance value at position M2 - (the sum of capacitance values ​​at positions M1 and M2) ÷ 2;

[0069] C. Divide the capacitance change of tuned motor M1 and tuned motor M2 into 100 equal parts, and calculate the movement distance of the electronic ruler corresponding to each capacitance change by fitting the curve.

[0070] D. Move tuning motors M1 and M2 according to the moving distance of the electronic ruler corresponding to each change in capacitance.

[0071] (2) Moving tuning motors M1, M2, and M3. Previously, only tuning motors M1 and M2 were in working state. Currently, tuning motors M1, M2, and M3 are all in working state.

[0072] A. After tuned motors M1 and M2 reach the desired capacitance change, treat tuned motors M1 and M2 as a whole or as a single tuned motor group. 12 View; tuned motor set 12 The capacitance change is the same for each tuned motor.

[0073] B. Tuning motor assembly 12 Change in capacitance = Tuned motor set 12 The capacitance value of any tuned motor - (the capacitance value of tuned motor at position M1 + the capacitance value of tuned motor at position M2 + the capacitance value of tuned motor at position M3) ÷ 3;

[0074] C. The change in capacitance of tuned motor M3 = capacitance value at position M3 - (capacitance value at position M1 + capacitance value at position M2 + capacitance value at position M3) ÷ 3;

[0075] D. Adjust the tuning motor sets respectively. 12 The capacitance change and the capacitance change of the tuned motor M3 are divided into 100 parts on average, and the movement distance of the electronic ruler corresponding to each part of the capacitance change is obtained by fitting a curve using a mathematical formula.

[0076] E. Move the tuning motor assembly according to the distance the electronic ruler moves for each change in capacitance. 12 Each tuned motor and tuned motor M3;

[0077] (3) The mobile tuning motors M1, M2, M3, and M4. Previously, only tuning motors M1, M2, and M3 were in working state. Currently, all tuning motors M1, M2, M3, and M4 are in working state.

[0078] A. After the tuning motor M1, the tuning motor M2, and the tuning motor M3 reach the desired capacitance variation, the tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group 123 A. The tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group 123 A. The tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group

[0079] B. The tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group 123 B. The tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group 123 B. The tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group 123 B. The tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group

[0080] C. The tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group

[0081] D. The tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group 123 D. The tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group

[0082] E. The tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group 123 E. The tuning motor M1, the tuning motor M2, and the tuning motor M3 are regarded as a whole or as a tuning motor group

[0083] It should be emphasized that the above specific embodiments are merely an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the above embodiments without creative contribution after reading the present specification, and the modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for tuning a four-cavity high-energy accelerator, the method being based on a four-cavity resonant cavity tuning device, the four-cavity resonant cavity tuning device comprising a transmitter, a four-cavity resonant cavity, a low-level control system, a directional coupler and a host computer; the head of cavity 1, cavity 2, cavity 3 and cavity 4 of the four-cavity resonant cavity are connected by a bridge, and each cavity is externally provided with a tuning motor M1, M2, M3 and M4, and each tuning motor is further provided with an electronic ruler for feeding back the position of the motor; the transmitter is used for amplifying the signal from the low-level control system and feeding into the four-cavity resonant cavity through a transmission line; the input end of the transmitter is connected to the low-level control system, and the output end is connected to cavity 1 and connected to cavity 2, cavity 3 and cavity 4 through the bridge; the four-cavity resonant cavity provides a stable high-frequency electric field for charged particles through resonance. The input end is connected with a transmitter, wherein, The cavity 2, cavity 3, cavity 4 are connected with the transmitter through the cavity 1; the low level control system controls the resonant capacitance of the resonant cavity cavity 1, cavity 2, cavity 3, cavity 4 through the tuning motor M1, M2, M3, M4 respectively, and obtains the internal power signal of the cavity 1, cavity 2, cavity 3, cavity 4 of the four-cavity resonant cavity, obtains the incident power signal from the directional coupler, the two signals are phase detected and control the tuning motor to tune the frequency of the resonant cavity; the directional coupler is arranged on the transmission line between the transmitter and the resonant cavity, which obtains the incident power signal from the transmitter, and samples as one of the signals of each tuning ring; The upper computer is bidirectionally connected with the low level control system; the upper computer communicates with the low level control system, and the upper computer controls the tuning of the four tuning rings through the positions of the current four tuning motors, and the tuning method comprises the following steps: Step one, an electronic ruler is arranged outside each cavity of the four-cavity resonant cavity, and the electronic ruler is used for feeding back the current position of the tuning motor; Step two, the initial positions of the tuning motors M1, M2, M3, M4 and the initial positions of the electronic rulers equipped with them are set, in order to reduce the movement distance of the motor and the change of the resonant point of the motor caused by the maintenance of the cavity, the four motors are homed to the position in the middle of the electronic ruler each time; Step three, the tuning motor M1 is moved, and the tuning motor M1 completes the search of the resonant point in the S1 state, the amplitude climbing in the S2 state, and the amplitude stable closed loop in the S3 state of the low level control system S1; the tuning motors M2, M3, M4 do not act during this period; Step four, the low level control system remains in the S3 state for a period of time to reach thermal equilibrium, and the judgment condition is time, which is set by the debugging experience; Step five, enter the S4 voltage deviation compensation stage: take the capacitance change as the step, and alternately adjust the capacitance change of the tuning motors M1, M2, M3, M4, so that the voltage deviation between the tuning motors M1, M2, M3, M4 approaches 0; The setting method of the capacitance change of step five is as follows: 1) establish a capacitance value and electronic ruler position table and fit it into a mathematical formula curve; 2) capacitance change = current required to move the capacitance value of the tuning motor position - (the sum of the capacitance values of the tuning motor positions required to move in the current stage) ÷ the number of motors to be moved in the current stage; the current includes S4-1 stage, S4-2 stage, S4-3 stage, and in the above stages, 2, 3, 4 motors are moved respectively; 3) divide the current tuning motor capacitance change into several parts, and obtain the moving distance of the electronic ruler corresponding to each part of the capacitance change through the mathematical formula fitting curve; 4) move the tuning motor according to the moving distance of the electronic ruler corresponding to each part of the capacitance change.

2. The method of tuning a four-cavity for a high-energy accelerator of claim 1, wherein, The initial positions of the four tuning motor electronic rulers are the same, and the lengths are the same, and the initial positions are the same, that is, the distances of the four electronic rulers from the resonant cavity are the same.

3. The method of tuning a four-cavity for a high-energy accelerator of claim 1, wherein, The step five of the alternative adjustment tunes the motor M1, M2, M3, M4 capacitor variation, so as to achieve the voltage deviation between the tuning motor M1, M2, M3, M4 close to 0, the specific process is as follows: (1) move the tuning motor M1, M2, before only the tuning motor M1 is in working condition, the current tuning motor M1 and the tuning motor M2 are in working condition; A, the tuning motor M1 capacitor variation=tuning motor M1 position capacitor value-(tuning motor M1 position capacitor value and tuning motor M2 position capacitor value)÷2; B, the tuning motor M2 capacitor variation=tuning motor M2 position capacitor value-(tuning motor M1 position capacitor value and tuning motor M2 position capacitor value)÷2; C, respectively, the tuning motor M1 tuning motor M2 capacitor variation is divided into 100 parts, and the moving distance of each part of the capacitor variation corresponding to the electronic ruler is calculated by fitting curve; D, according to the moving distance of each part of the capacitor variation corresponding to the electronic ruler, move the tuning motor M1 and the tuning motor M2; (2) move the tuning motor M1, M2, M3, before only the tuning motor M1 and the tuning motor M2 are in working condition, the current tuning motor M1, tuning motor M2, tuning motor M3 are in working condition; A. After the tuning motor M1 and the tuning motor M2 reach the desired amount of capacitance change, the tuning motor M1 and the tuning motor M2 are regarded as a whole or as a tuning motor group 12 regarded as a whole; tuning motor group 12 The amount of capacitance change of each tuning motor is the same; B. Tuning motor group 12 Capacitance variation = tuning motor group 12 Capacitance value of any tuning motor = (Capacitance value at tuning motor M1 position + Capacitance value at tuning motor M2 position + Capacitance value at tuning motor M3 position) ÷ 3; C. the tuning motor M3 capacitor variation=tuning motor M3 position capacitor value-(tuning motor M1 position capacitor value+tuning motor M2 position capacitor value+tuning motor M3 position capacitor value)÷3; D, respectively, the tuning motor set 12 The capacitance change amount and the capacitance change amount of the tuning motor M3 are evenly divided into 100 parts, and the moving distance of the electronic ruler corresponding to each part of the capacitance change amount is obtained by fitting a curve through a mathematical formula. E、According to the moving distance of the electronic ruler corresponding to the change amount of each capacitor, the tuning motor group is moved respectively 12 Each tuning motor and the tuning motor M3 (3) move the tuning motor M1, M2, M3, M4, before only the tuning motor M1, tuning motor M2, tuning motor M3 are in working condition, the current tuning motor M1, tuning motor M2, tuning motor M3, tuning motor M4 are in working condition; A. After the tuning motor M1, the tuning motor M2, the tuning motor M3 reach the desired capacitance variation, the tuning motor M1, the tuning motor M2, the tuning motor M3 are regarded as a whole or as a tuning motor group 123 regarded as a whole; the tuning motor group 123 The capacitance variation of each tuning motor in the tuning motor group is the same B. Tuning motor group 123 The capacitance variation amount of the tuning motor group = (The capacitance value of the tuning motor M1 position + The capacitance value of the tuning motor M2 position + The capacitance value of the tuning motor M3 position + The capacitance value of the tuning motor M4 position) ÷ 4 123 The capacitance variation amount of any tuning motor in the tuning motor group = (The capacitance value of the tuning motor M1 position + The capacitance value of the tuning motor M2 position + The capacitance value of the tuning motor M3 position + The capacitance value of the tuning motor M4 position) ÷ 4; tuning motor group 123 The capacitance variation amount of each tuning motor in the tuning motor group is the same; C. the tuning motor M4 capacitor variation=tuning motor M4 position capacitor value-(tuning motor M1 position capacitor value+tuning motor M2 position capacitor value+tuning motor M3 position capacitor value+tuning motor M4 position capacitor value)÷4; D, respectively, the tuning motor set 123 The capacitance change amount and the capacitance change amount of the tuning motor M4 are evenly divided into 100 parts, and the moving distance of the electronic ruler corresponding to each part of the capacitance change amount is obtained by fitting a curve through a mathematical formula. E、According to the moving distance of the electronic ruler corresponding to the change amount of each capacitor, the tuning motor group is moved respectively 123 each tuning motor and the tuning motor M4.

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