Medical cyclotron beam sliding phase measurement method and system

Abstract

The invention relates to the technical field of plasma, in particular to a medical cyclotron beam sliding phase measurement method and system. The method comprises the following steps: collecting beam intensity, and obtaining a target amount; dividing the target quantity into two parts, obtaining a symmetric target quantity, obtaining an interference source sequence based on the front target quantity and the symmetric target quantity, obtaining interference intensity based on the front target quantity and the rear target quantity, and processing the interference source sequence to obtain an interference source intensity sequence; processing the interference source intensity sequence to obtain interference source fluctuation intensity so as to determine a beam intensity upper limit; determining a beam intensity ratio based on the beam intensity upper limit and all the beam intensities of the target amount; acquiring a sliding phase sine value based on the relationship between the phase difference and the beam intensity ratio; recording the current increment; and calculating the beam sliding phase according to the sliding phase sine value and the current increase value to complete the measurement of the beam sliding phase. According to the invention, the accuracy of a beam sliding phase measurement result is improved.

Description

Technical Field

[0001] The present application relates to the field of plasma technology, and in particular to a method and system for measuring beam slip phase of a medical cyclotron. Background Art

[0002] Beam phase slippage refers to the phenomenon in medical cyclotron accelerators where charged particles perform circular motion in a magnetic field. Due to magnetic field inhomogeneities or instability in the high-frequency electric field, this can cause a mismatch between the rotational phase of the particles' rotational motion caused by the magnetic field and the phase shift of the high-frequency magnetic field. This mismatch can affect particle acceleration efficiency, thereby impacting beam quality and the ultimate acceleration effect. To ensure effective particle acceleration, phase slippage measurements of the medical cyclotron particle beam are required to adjust the high-frequency magnetic field phase for optimal particle acceleration.

[0003] Existing methods obtain the existence and magnitude of phase slip based on the asymmetry of the current change. This method of measuring phase slip involves frequently adjusting the current and measuring the beam intensity, which is a cumbersome and time-consuming process. Frequent adjustment of the superconducting coil current may affect the stability of the accelerator, thereby affecting the accuracy of the measurement results. Therefore, in the existing medical cyclotron beam phase slip measurement method, there is a risk of decreased accelerator stability due to frequent adjustment of the superconducting coil current, which in turn affects the accuracy of the final measurement results. Summary of the Invention

[0004] In order to solve the technical problem of inaccurate phase-slip measurement, this application provides a method and system for measuring phase-slip of a medical cyclotron beam. The technical solutions adopted are as follows: In a first aspect, the present application proposes a method for measuring beam slippage in a medical cyclotron, the method comprising the following steps: Collect the beam intensity at each moment on the radial target, and record the vector composed of all beam intensities as the targeting quantity; The targeting amount is divided into two parts, namely the front targeting amount and the back targeting amount, and the back targeting amount is symmetrically processed to obtain the symmetrical targeting amount; the interference source sequence is determined based on the difference in beam intensity at the same position of the front targeting amount and the back targeting amount; the difference in the mean beam intensity of the front targeting amount and the back targeting amount is used to analyze and obtain the interference intensity in the acceleration zone, and the interference source intensity sequence is determined by the difference between the interference source sequence and the interference intensity in the acceleration zone; the interference source intensity sequence is processed using the 3 sigma principle to obtain the interference source fluctuation intensity; and the upper limit of the beam intensity is determined by multiplying the interference source fluctuation intensity by the preset intensity; Determine the beam intensity ratio based on the upper limit of the beam intensity and all the beam intensities of the targeted amount; obtain the relationship between the beam intensity ratio and the phase difference by analyzing the width of the bunch; and substitute the relationship into the sine formula of the phase difference to obtain the phase-slip sine value; Record the current increase when the beam intensity reaches the upper limit of the beam intensity; calculate the beam phase sliding based on the phase sliding sine value and the current increase value to complete the beam phase sliding measurement.

[0005] In the above scheme, the present application measures the beam intensity through a radial target to obtain a radial target data vector; obtains a calculated interference source sequence through the symmetric characteristics of the radial target data vector signal, and extracts the interference source characteristics during beam intensity measurement; calculates the interference intensity of the acceleration zone due to the asymmetry of the radial target data vector caused by the asymmetric acceleration of particles when the beam passes through the acceleration zone of the medical cyclotron, and uses the acceleration zone interference intensity to process the interference source sequence to obtain an interference source intensity sequence to characterize the beam intensity generated by the interference source in the medical cyclotron; further calculates the interference source fluctuation intensity through the interference source intensity sequence, and uses this to set the upper limit of the beam intensity to adjust the superconducting coil current control conditions during beam phase sliding measurement; finally, obtains the measurement data of the beam phase sliding through the obtained superconducting coil current control conditions, and calculates the size of the beam phase sliding. Among them, since the present application extracts the interference source noise in the beam intensity signal, the superconducting coil current control conditions are adjusted while ensuring that the interference source noise does not affect the final result, thereby reducing the frequent adjustment of the superconducting coil current and avoiding the problem of decreased accelerator stability caused by frequent adjustment of the superconducting coil current, thereby improving the accuracy of the beam sliding phase measurement results.

[0006] In one embodiment, the method of dividing the targeting amount into two parts, recorded as a front targeting amount and a rear targeting amount, and symmetrically processing the rear targeting amount to obtain a symmetric targeting amount is: The target volume is evenly divided from the middle, the front part is the front target volume, and the back part is the back target volume; the back target volume is processed centrally and symmetrically to obtain the symmetrical target volume.

[0007] In one embodiment, the method for determining the interference source sequence based on the beam intensity difference at the same position of the front target amount and the rear target amount is: The ratio of the absolute value of the difference between the beam intensity at the same position in the front targeting amount and the symmetric targeting amount to the constant 2 is used as the element value; the sequence composed of the element values ​​in the order of the same position is used as the interference source sequence.

[0008] In one embodiment, the method of analyzing the difference between the mean beam intensities of the pre-targeted quantity and the post-targeted quantity to obtain the acceleration zone interference intensity, and determining the interference source intensity sequence by the difference between the interference source sequence and the acceleration zone interference intensity is as follows: Let the ratio of the difference between the mean of the front-targeting element and the mean of the back-targeting element and the constant 2 be the interference intensity of the acceleration zone; The sequence obtained by subtracting the value of each element in the interference source sequence from the interference intensity of the acceleration zone is used as the interference source intensity sequence.

[0009] In one embodiment, the method of processing the interference source intensity sequence using the 3 sigma principle to obtain the interference source fluctuation intensity is: Calculate the mean and standard deviation of the sequence values ​​in the interference source intensity sequence, and let the sum of the mean and three times the standard deviation be the interference source fluctuation intensity.

[0010] In one embodiment, the method for determining the beam intensity ratio based on the beam intensity upper limit and all beam intensities of the targeted amount is: The average beam intensity of the targeted amount at all times is calculated as the beam intensity of the targeted amount, and the ratio of the beam intensity upper limit to the beam intensity of the targeted amount is recorded as the beam intensity ratio.

[0011] In one embodiment, the relationship between the beam intensity ratio and the phase difference obtained by analyzing the width of the bunch is: , is the beam intensity ratio, 2 is the definite integral of the sine function from 0 to 180°, The sine function goes from 0 to The definite integral of It is the phase difference between the beam rotation phase and the accelerating electric field phase.

[0012] In one embodiment, the method of substituting the relationship into the sine formula of the phase difference to obtain the phase-sliding sine value is: , is the beam intensity ratio, is the sine value of the sliding phase.

[0013] In one embodiment, the current increase when the beam intensity reaches the upper limit of the beam intensity is recorded; and the beam phase sliding is calculated according to the phase sliding sine value and the current increase value as follows: When the superconducting coil current is lowered, the increase in current when the beam intensity reaches the upper limit of the beam intensity is recorded as When the superconducting coil current is increased, the increase in current when the beam intensity reaches the upper limit of the beam intensity is recorded as ; The expression of beam sliding phase is: , is the magnitude of the beam sliding phase, is the inverse function of the sine function, is the sliding phase sine value, and is the current increase of the two superconducting coils.

[0014] In a second aspect, an embodiment of the present application also provides a medical cyclotron beam phase-slip measurement system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-mentioned medical cyclotron beam phase-slip measurement methods.

[0015] The beneficial effects of this application are: The present application measures beam intensity through a radial target to obtain a radial target data vector; obtains a calculated interference source sequence based on the symmetric characteristics of the radial target data vector signal and extracts the interference source characteristics during beam intensity measurement; calculates the interference intensity of the acceleration zone due to the asymmetric acceleration of particles when the beam passes through the acceleration zone of a medical cyclotron, and uses the acceleration zone interference intensity to process the interference source sequence to obtain an interference source intensity sequence to characterize the beam intensity generated by the interference source in the medical cyclotron; further calculates the interference source fluctuation intensity based on the interference source intensity sequence, and uses this to set the upper limit of the beam intensity to adjust the superconducting coil current control conditions during beam phase sliding measurement; finally, obtains beam phase sliding measurement data based on the obtained superconducting coil current control conditions and calculates the beam phase sliding magnitude. Among them, because the present application extracts the interference source noise in the beam intensity signal, the superconducting coil current control conditions are adjusted while ensuring that the interference source noise does not affect the final result, reducing the frequent adjustment of the superconducting coil current and avoiding the problem of accelerator stability degradation caused by frequent adjustment of the superconducting coil current, thereby improving the accuracy of the beam phase sliding measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 A flow chart of a medical cyclotron beam phase slip measurement method provided in one embodiment of the present application; Figure 2 Schematic diagram of a cyclotron. DETAILED DESCRIPTION

[0018] To further illustrate the technical means and effectiveness of this application to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effectiveness of a medical cyclotron beam phase measurement method and system proposed in this application. In the following description, references to different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0019] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0020] A medical cyclotron beam phase sliding measurement method embodiment: The specific scheme of the medical cyclotron beam sliding phase measurement method provided by the present application is described in detail below with reference to the accompanying drawings.

[0021] See also Figure 1 , which shows a flow chart of a medical cyclotron beam phase sliding measurement method provided by one embodiment of the present application, the method comprising the following steps: Step S001: collecting the beam intensity at each moment on the radial target, and recording the vector formed by all beam intensities as the targeting quantity.

[0022] Because beam slippage causes an asymmetric response of beam intensity to changes in superconducting coil current, existing methods use this asymmetric characteristic to reflect the magnitude of beam slippage. However, this requires changing the superconducting coil current. In the process of adjusting the superconducting coil current, the stability of the medical cyclotron is easily reduced, which in turn leads to deviations in the measurement results and affects the accuracy of the measurement results.

[0023] The intensity of the medical cyclotron beam is measured using a radial target. The measurement result is the beam signal intensity, which represents the number of particles hitting the radial target in the medical cyclotron at a certain moment. Figure 2 shown. Figure 2 In the figure, 1 is the trajectory of the water flow, 2 is the D-box of the medical cyclotron, 3 is the electric field line of the accelerator of the medical cyclotron, and 4 is the radial target placed in the medical cyclotron.

[0024] The radial target is perpendicular to the accelerating electric field, so the time it takes for the bunch to reach the radial target is one-quarter of the particle's rotational motion. The moment the bunch reaches the radial target coincides with the moment the medical cyclotron RF signal reaches its maximum value. After the bunch reaches the radial target, its duration is one-half of the particle's rotational motion, and the data collection period is also one-half of the particle's rotational motion. That is, radial target data collection begins when the signal reaches its maximum value, and the collection period lasts for one-half of the particle's rotational motion.

[0025] In this embodiment, the medical cyclotron uses an acceleration frequency of A = 75 MHz for acceleration, and the sampling frequency of the radial target is B = 2000 times the sampling frequency of the medical cyclotron to measure the beam intensity. The sampling frequency of the radial target is C = 150 GHz. .

[0026] The collected radial target data is formed into a vector and recorded as the targeting quantity, whose length is , where the nth element represents the beam intensity at time n.

[0027] At this point, the beam intensity at each moment is obtained.

[0028] Step S002: Divide the targeting amount into two parts, obtain the symmetric targeting amount, obtain the interference source sequence based on the front targeting amount and the symmetric targeting amount, obtain the interference intensity based on the front targeting amount and the back targeting amount, process the interference source sequence to obtain the interference source intensity sequence; process the interference source intensity sequence to obtain the interference source fluctuation intensity, so as to determine the upper limit of the beam intensity.

[0029] The beam in the accelerator exists in the form of plasma, which is called a bunch. In the absence of environmental interference sources, after the bunch passes through the acceleration zone of the medical cyclotron, its energy is controlled by the radio frequency signal that can accelerate the particles in the acceleration zone. The greater the energy provided by the radio frequency signal in the acceleration zone, the greater the total energy of the particles in the corresponding area inside the bunch, and the greater the beam intensity measured after it hits the radial target.

[0030] Because the RF signal is symmetrical within a cycle, the resulting target quantity, in the absence of interference, is also a front-to-back symmetric vector. Furthermore, the asymmetric signal portion of the target quantity can be considered to be beam intensity interference caused by interference sources within the cyclotron.

[0031] The targeting amount is split in the middle, with the front portion being the front targeting amount and the rear portion being the rear targeting amount. In this embodiment, the first 500 beam intensities constitute the front targeting amount, and the rear 500 beam intensities constitute the rear targeting amount. Furthermore, the rear targeting amount is subjected to centrosymmetric processing, which means that the first element is swapped with the last element, the second element is swapped with the second-to-last element, and so on, until the 250th element and the 251st element are swapped. The resulting vector is recorded as the symmetric targeting amount.

[0032] The difference between the elements at the same position in the pre-targeting amount and the symmetric targeting amount constitutes an interference source sequence. This interference source sequence characterizes the impact of internal interference sources in the cyclotron on the measured radial target beam intensity. In this embodiment, the ratio of the absolute value of the difference between the elements at the same position in the pre-targeting amount and the symmetric targeting amount to a constant 2 is used as the element value of the interference source sequence.

[0033] Ideally, the time it takes for beam particles to pass through the acceleration zone is extremely short, so the intensity of the accelerating electric field to which the beam particles are subjected can be considered constant as they move through the acceleration zone. In this case, if there are no interference sources, the targeting quantity should be a strictly front-to-back symmetric vector. However, within an actual medical cyclotron accelerator, the accelerating electric field is controlled by radio frequency signals and changes as the beam particles pass through the acceleration zone. Therefore, the acceleration of the particles corresponding to the front targeting quantity gradually increases as they pass through the acceleration zone, while the acceleration of the particles corresponding to the rear targeting quantity gradually decreases. Consequently, the kinetic energy of the particles corresponding to the front targeting quantity is greater than that of the particles corresponding to the rear targeting quantity. This results in the targeting quantity not being a strictly front-to-back symmetric vector, and the overall beam intensities represented by the front and rear targeting quantities differ.

[0034] Therefore, the interference intensity of the acceleration zone is calculated for the interference source sequence to remove the influence of asymmetric acceleration of particles in the acceleration zone on the interference source feature extraction.

[0035] Calculate the mean of all elements in the front targeting amount and the mean of all elements in the back targeting amount, and let the ratio of the difference between the mean of the front targeting amount and the mean of the back targeting amount to the constant 2 be the interference intensity of the acceleration zone.

[0036] Among them, the mean of the pre-targeting quantity and the post-targeting quantity respectively represent the corresponding beam intensity size, and the difference represents the difference in beam intensity between the two based on the interference of the acceleration zone, which represents the beam intensity interference caused by the asymmetric acceleration in the acceleration zone on the interference source feature extraction; finally, divided by 2 for numerical processing, the acceleration zone interference intensity is obtained. The larger the value, the more the beam intensity characteristics represented by the interference source sequence are caused by the asymmetric acceleration of particles in the acceleration zone.

[0037] Subtract the acceleration zone interference intensity from each element value in the interference source sequence to obtain the interference source intensity sequence, which represents the beam intensity fluctuation caused by the interference source in the targeting amount.

[0038] The interference source intensity sequence is the interference signal caused by the interference source on the beam intensity. As a noise signal generator, the interference on the beam intensity is relatively random. Therefore, this embodiment estimates the maximum fluctuation value of the interference source according to the 3 sigma principle and records the maximum fluctuation value as the interference source fluctuation intensity. The specific method is as follows: Calculate the mean and standard deviation of the sequence values ​​in the interference source intensity sequence, and let the sum of the mean and three times the standard deviation be the interference source fluctuation intensity.

[0039] According to the 3 sigma principle, the fluctuation range of the data is between its mean plus plus or minus three times the standard deviation. Therefore, in this embodiment, the mean plus three times the standard deviation is used as the maximum fluctuation value caused by the interference source to the beam intensity measurement. The larger this value is, the larger the adjusted beam intensity range should be when performing beam sliding measurement to eliminate the influence of the interference source on the beam sliding measurement.

[0040] When the adjusted beam intensity range is greater than n times the interference source fluctuation intensity, the interference source fluctuation will not affect the beam intensity range. In this embodiment, n takes an empirical value of 50.

[0041] Finally, when performing beam phase sliding measurement, the medical cyclotron is operated, and the interference source fluctuation intensity is calculated according to the scheme described in this embodiment and multiplied by the empirical constant n. The obtained value is recorded as the upper limit of the beam intensity, which is used to guide the superconducting coil current adjustment during the beam phase sliding measurement.

[0042] At this point, the upper limit of the beam intensity is obtained.

[0043] Step S003: determining a beam intensity ratio based on the upper limit of the beam intensity and all beam intensities of the targeted amount; obtaining a relationship between the beam intensity ratio and the phase difference by analyzing the width of the bunch; and substituting the relationship into the sine formula of the phase difference to obtain a phase-slip sine value.

[0044] After obtaining the upper limit of the beam intensity according to the above steps, the average of the beam intensities at all times of the targeted amount is calculated as the beam intensity of the targeted amount, and the ratio of the beam intensity upper limit to the beam intensity of the targeted amount is recorded as the beam intensity ratio.

[0045] Among them, when measuring the beam phase slip later, the magnetic field will be controlled by adjusting the current of the superconducting coil. The magnetic field controls the phase of the beam rotation. The change in the beam rotation phase causes a phase difference between the beam rotation phase and the phase of the accelerating electric field. The phase difference causes the acceleration effect of the accelerating electric field to decrease, and ultimately causes the beam intensity to decrease until the beam intensity drops to meet the beam intensity ratio.

[0046] The beam intensity ratio represents the magnitude of the beam slip phase generated by the active control magnetic field. The beam intensity ratio can be used to calculate the phase difference between the beam rotation phase and the acceleration electric field phase after the active control magnetic field is obtained.

[0047] The phase difference between the beam rotation phase and the accelerating electric field phase is called the phase slip at any radial position of the particle. This phase difference is needed when calculating the beam phase slip size through the measurement data. Therefore, the sine value of this phase difference needs to be calculated. .

[0048] Due to the artificially controlled beam phase slip, the beam particles within the phase difference between the beam rotation phase and the accelerating electric field phase cannot be accelerated. These particles cannot be measured by the radial target, which leads to a decrease in beam intensity. The accelerator beam is a bunch, which has a certain phase width. In the cyclotron accelerator, the acceleration of the beam in the acceleration zone lasts for half a cycle and has a sinusoidal waveform. Therefore, the phase width of the accelerator beam is 180°, and the energy distribution of its beam particles is a sinusoidal waveform. Therefore, the relationship between the beam intensity ratio and the phase difference is: , is the beam intensity ratio, 2 is the definite integral of the sine function from 0 to 180°, The sine function goes from 0 to The definite integral of It is the phase difference between the beam rotation phase and the accelerating electric field phase.

[0049] The definite integral of the sine function from 0 to 180° represents the total energy of the accelerated particles if all particles are accelerated during half a period of acceleration. The definite integral shows that if there is a phase difference ,exist Particles within the phase width of 180° are not accelerated, deviate from the orbit and cannot be measured by the radial target, while the definite integral value represents the total energy of the actual accelerated particles; the ratio of the two energies is the ratio of the particle energies before and after the phase slip, which corresponds to the beam intensity ratio.

[0050] The sine of the phase difference Substitute this into the relationship between beam intensity ratio and phase difference to obtain the phase-sliding sine value, and we get the following relationship: , is the beam intensity ratio, is the sine value of the sliding phase.

[0051] At this point, the sliding phase sine value is obtained.

[0052] Step S004 , recording the current increase when the beam intensity reaches the upper limit of the beam intensity; calculating the beam phase sliding according to the phase sliding sine value and the current increase value, and completing the measurement of the beam phase sliding.

[0053] When the superconducting coil current is continuously increased in small steps until the beam intensity measured on the radial target is equal to the upper limit of the beam intensity, the increase in the superconducting coil current at this time is recorded. Continuously reduce the superconducting coil current in smaller steps until the beam intensity measured on the radial target is equal to the upper limit of the beam intensity, and record the increase in the superconducting coil current at this time .

[0054] The beam current sliding phase is calculated based on the sliding phase sine value and the increase in the current of the two superconducting coils through the sliding phase measurement calculation formula. The expression is: , is the beam sliding phase size, is the inverse function of the sine function, is the sliding phase sine value, and is the current increase of the two superconducting coils.

[0055] It should be noted that the existing beam phase sliding size calculation method does not have the phase sliding sine value term, that is, there is no This is because the existing beam current sliding phase size calculation method sets the beam current intensity ratio to is one-half, and the calculation result of the sliding phase sine value is obtained Therefore, the phase-slip sine value term does not appear in its calculation method; the calculation formula for the beam phase-slip size is a public technology in the field of plasma technology.

[0056] This completes the beam-slip measurement of a medical cyclotron. Because this embodiment extracts interference source noise from the beam intensity signal, it adjusts the superconducting coil current control conditions while ensuring that the interference source noise does not affect the final result. This reduces the need for frequent superconducting coil current adjustments, avoids the resulting decrease in accelerator stability, and thus improves the accuracy of the beam-slip measurement results.

[0057] Based on the same inventive concept as the above-mentioned method, an embodiment of the present invention also provides a medical cyclotron beam phase-slip measurement system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of any one of the above-mentioned medical cyclotron beam phase-slip measurement methods are implemented.

[0058] It should be noted that the above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and should all be included in the scope of protection of the present application.

[0059] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A method for measuring beam slip phase of a medical cyclotron, characterized in that: The method comprises the following steps: Collect the beam intensity at each moment on the radial target, and record the vector composed of all beam intensities as the targeting quantity; The targeting amount is divided into two parts, namely the front targeting amount and the back targeting amount, and the back targeting amount is symmetrically processed to obtain the symmetrical targeting amount; the interference source sequence is determined based on the difference in beam intensity at the same position of the front targeting amount and the back targeting amount; the difference in the mean beam intensity of the front targeting amount and the back targeting amount is used to analyze and obtain the interference intensity in the acceleration zone, and the interference source intensity sequence is determined by the difference between the interference source sequence and the interference intensity in the acceleration zone; the interference source intensity sequence is processed using the 3 sigma principle to obtain the interference source fluctuation intensity; and the upper limit of the beam intensity is determined by multiplying the interference source fluctuation intensity by the preset intensity; Determine the beam intensity ratio based on the upper limit of the beam intensity and all the beam intensities of the targeted amount; obtain the relationship between the beam intensity ratio and the phase difference by analyzing the width of the bunch; and substitute the relationship into the sine formula of the phase difference to obtain the phase-slip sine value; Record the current increase when the beam intensity reaches the upper limit of the beam intensity; calculate the beam phase sliding based on the phase sliding sine value and the current increase value to complete the beam phase sliding measurement.

2. A medical cyclotron beam phase sliding measurement method according to claim 1, characterized in that: The method of dividing the targeting amount into two parts, namely the front targeting amount and the back targeting amount, and symmetrically processing the back targeting amount to obtain the symmetrical targeting amount is as follows: The target volume is evenly divided from the middle, the front part is the front target volume, and the back part is the back target volume; the back target volume is processed centrally and symmetrically to obtain the symmetrical target volume.

3. The medical cyclotron beam phase sliding measurement method according to claim 1, characterized in that: The method for determining the interference source sequence based on the difference in beam intensity at the same position of the front targeting amount and the rear targeting amount is: The ratio of the absolute value of the difference between the beam intensity at the same position in the front targeting amount and the symmetric targeting amount to the constant 2 is used as the element value; the sequence composed of the element values ​​in the order of the same position is used as the interference source sequence.

4. The method for measuring beam phase slip of a medical cyclotron according to claim 1, wherein: The method of analyzing the difference between the mean values ​​of the beam intensities of the front-target quantity and the rear-target quantity to obtain the interference intensity in the acceleration zone, and determining the interference source intensity sequence by the difference between the interference source sequence and the interference intensity in the acceleration zone is as follows: Let the ratio of the difference between the mean of the front-targeting element and the mean of the back-targeting element and the constant 2 be the interference intensity of the acceleration zone; The sequence obtained by subtracting the value of each element in the interference source sequence from the interference intensity of the acceleration zone is used as the interference source intensity sequence.

5. The medical cyclotron beam phase sliding measurement method according to claim 1, characterized in that: The method for processing the interference source intensity sequence using the 3 Sigma principle to obtain the interference source fluctuation intensity is: Calculate the mean and standard deviation of the sequence values ​​in the interference source intensity sequence, and let the sum of the mean and three times the standard deviation be the interference source fluctuation intensity.

6. The method for measuring beam phase slip of a medical cyclotron according to claim 1, wherein: The method for determining the beam intensity ratio based on the beam intensity upper limit and all beam intensities of the targeted amount is: The average beam intensity of the targeted amount at all times is calculated as the beam intensity of the targeted amount, and the ratio of the beam intensity upper limit to the beam intensity of the targeted amount is recorded as the beam intensity ratio.

7. The medical cyclotron beam phase sliding measurement method according to claim 1, characterized in that: The relationship between the beam intensity ratio and the phase difference obtained by analyzing the width of the bunch is: , is the beam intensity ratio, 2 is the definite integral of the sine function from 0 to 180°, The sine function goes from 0 to The definite integral of It is the phase difference between the beam rotation phase and the accelerating electric field phase.

8. The method for measuring beam phase slip of a medical cyclotron according to claim 1, wherein: The method of substituting the relationship into the sine formula of the phase difference to obtain the phase-slip sine value is: , is the beam intensity ratio, is the sine value of the sliding phase.

9. The medical cyclotron beam phase sliding measurement method according to claim 1, characterized in that: The current increase when the recording beam intensity reaches the upper limit of the beam intensity; The method for calculating beam current sliding phase based on the sliding phase sine value and current increase value is: When the superconducting coil current is lowered, the increase in current when the beam intensity reaches the upper limit of the beam intensity is recorded as When the superconducting coil current is increased, the increase in current when the beam intensity reaches the upper limit of the beam intensity is recorded as ; The expression of beam sliding phase is: , is the magnitude of the beam sliding phase, is the inverse function of the sine function, is the sliding phase sine value, and is the current increase of the two superconducting coils.

10. A medical cyclotron beam phase slip measurement system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the medical cyclotron beam phase sliding measurement method according to any one of claims 1 to 9 are implemented.

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