Deflection cavity cavity field distribution tuning method, device and readable storage medium

Abstract

The application provides a deflection cavity cavity field distribution tuning method, equipment and readable storage medium, the deflection cavity cavity field distribution tuning method comprises the following steps: driving a perturbation body to move along an axial path, and detecting and recording the axial disturbance amount at each cavity on the axial path through the perturbation body; driving the perturbation body to move along an off-axis path, and detecting and recording the off-axis disturbance amount at each cavity on the off-axis path through the perturbation body; the off-axis path is located on the same vertical plane as the axial path; according to the axial disturbance amount and the off-axis disturbance amount, the longitudinal electric field is calculated; and the cavity of the deflection cavity is tuned according to the longitudinal electric field. In the application, the deflection cavity is tuned directly by measuring the longitudinal electric field, the influence of the transverse magnetic field and the transverse electric field error on the tuning effect is prevented, and the tuning accuracy of the deflection cavity is improved.

Description

Technical Field

[0001] This invention relates to the field of accelerator deflection cavity tuning technology, and more particularly to a method, apparatus and readable storage medium for tuning the field distribution of a deflection cavity. Background Technology

[0002] Deflection cavities are key components of accelerators and are widely used in high-energy physics. When a deflection cavity is in operation, it excites specific radio frequency resonant modes within the cavity, creating a periodic transverse alternating electric and magnetic field in the cavity axis region. When a charged particle beam passes through the cavity axis, the electromagnetic field exerts a Lorentz force on the particles. By controlling the direction and magnitude of this force, transverse deflection, focusing, or trajectory correction of the beam can be achieved. This has important applications in beam measurement and manipulation, femtosecond laser-beam synchronization, and diagnostics of ultrashort FEL radiation pulses.

[0003] Specifically, to ensure that the parameters of the deflection cavity match the physical design requirements and to guarantee its normal operation, the deflection cavity needs to be tuned. Existing deflection cavity tuning often involves placing a dielectric sphere inside the cavity, passing it sequentially along the axis of the cavity. The electric field strength at the corresponding location within the cavity is determined by the disturbance, and the detuning amount of that cavity is calculated for tuning. Since there are transverse magnetic and electric fields along the axis of the deflection cavity, the dielectric material used for the sphere must only affect the electric field to prevent both from contributing to the perturbation. However, the measured transverse electric field amplitude is determined by both adjacent cavities. Therefore, the detuning amount calculated from the measured field cannot obtain an accurate tuning value; it is actually the superposition of the detuning amounts of the two cavities, resulting in a large error in the tuning result and low tuning accuracy.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method, device and readable storage medium for tuning the field distribution of a deflection cavity, so as to solve the problem that the transverse electric field affects the tuning accuracy during existing deflection cavity tuning.

[0006] The technical solution of the present invention is as follows: This invention provides a method for tuning the field distribution of a deflection cavity, the steps of which include: Drive the perturbation body to move along the axial path, and detect and record the axial perturbation at each cavity along the axial path through the perturbation body; The perturbation body is driven to move along an off-axis path, and the off-axis perturbation at each cavity along the off-axis path is detected and recorded by the perturbation body; the off-axis path and the axial path are located on the same vertical plane; The longitudinal electric field is calculated based on the axial disturbance and the off-axis disturbance. The cavity of the deflection cavity is tuned according to the longitudinal electric field.

[0007] In a further embodiment of the present invention, the step of driving the micro-perturbator to move along the axial path and detecting and recording the axial perturbation at each cavity along the axial path via the micro-perturbator includes: Set the perturbation on the axis path; The first perturbationless body reflection coefficient when the perturbation is outside the cavity was detected and recorded using a network analyzer. The perturbation body is driven by an external motor to move at a constant speed along the axial path, and the first perturbation body reflection coefficient when the perturbation body is set in each cavity is measured by a network analyzer. The axial disturbance is obtained based on the difference between the reflection coefficient of the first unperturbed body and the reflection coefficient of the first perturbed body.

[0008] A further provision of the present invention includes the step of driving the micro-perturbator to move along an off-axis path, and detecting and recording the off-axis perturbation at each cavity along the off-axis path using the micro-perturbator; wherein the off-axis path and the axial path are located on the same vertical plane. The perturbation body is fixed on an off-axis path, wherein the off-axis path and the axial path are located in the same vertical plane; The reflection coefficient of the second perturbationless body when the perturbation is outside the cavity is detected and recorded using a network analyzer. The perturbation is driven by an external motor to move at a constant speed along an off-axis path, and the reflection coefficient of the second perturbation when the perturbation is set in each cavity is measured by a network analyzer. The off-axis perturbation is obtained from the difference between the reflection coefficient of the second perturbationless body and the reflection coefficient of the second perturbation-bearing body.

[0009] In a further embodiment of the present invention, the off-axis path is obtained by offsetting the axial path along the polarization direction, and the off-axis path is parallel to the axial path.

[0010] A further provision of the present invention includes the step of calculating the longitudinal electric field based on the axial perturbation and the off-axis perturbation, comprising: For each cavity, the axial disturbance and off-axis disturbance of each cavity are read separately; The change in reflection coefficient is obtained based on the difference between the axial disturbance and the off-axis disturbance. The longitudinal electric field is obtained by normalizing the change in the reflection coefficient perturbation.

[0011] A further provision of the present invention includes the step of normalizing the change in the reflection coefficient perturbation to obtain the longitudinal electric field at each cavity, which comprises: Calculate the square root of the change in the reflection coefficient disturbance to obtain the continuous change value of the longitudinal electric field; Based on the continuously changing value of the longitudinal electric field, the peak value of the field in each cavity is obtained, and the peak value of the field is the longitudinal electric field at each cavity.

[0012] In a further embodiment of the present invention, the step of tuning the cavity of the deflection cavity according to the longitudinal electric field includes: Based on the longitudinal electric field, the forward and reverse waves of the cavity are calculated; Based on the forward and reverse waves, the cavity detuning of each cavity is calculated; the cavity resonant frequency is adjusted according to the cavity detuning to tune the cavity of the deflection cavity.

[0013] In a further embodiment of the present invention, the deflection cavity has two modes.

[0014] Based on the same inventive concept, the present invention also provides a computer device, which includes at least one processor, at least one memory, a communication interface, and a bus; wherein, The processor, memory, and communication interface communicate with each other through the bus; the memory stores program instructions that can be executed by the processor, and when the processor calls the program instructions, it implements the deflection cavity field distribution tuning method as described in any one of claims 1-8.

[0015] Based on the same inventive concept, the present invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a computer processor, causes the computer to perform the deflection cavity field distribution tuning method described above.

[0016] This invention provides a method, device, and readable storage medium for tuning the field distribution of a deflection cavity. The method includes: driving a micro-perturbation body to move along an axial path, and detecting and recording the axial perturbation at each cavity along the axial path using the micro-perturbation body; driving the micro-perturbation body to move along an off-axis path, and detecting and recording the off-axis perturbation at each cavity along the off-axis path using the micro-perturbation body; the off-axis path and the axial path are located in the same vertical plane; calculating the longitudinal electric field based on the axial perturbation and the off-axis perturbation; and tuning the cavity of the deflection cavity based on the longitudinal electric field. This invention directly tunes the deflection cavity by measuring the longitudinal electric field, preventing errors in the transverse magnetic field and transverse electric field from affecting the tuning effect and improving the tuning accuracy of the deflection cavity. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a schematic flowchart of the deflection cavity field distribution tuning method in this invention.

[0019] Figure 2 This is a schematic diagram of the transverse electric field existing inside the beam aperture.

[0020] Figure 3 These are dispersion curves of the deflection cavity, single-cavity chain model, and dual-cavity chain model in this invention.

[0021] Figure 4 This is a schematic diagram of the structure of the deflection cavity field distribution tuning method in the prior art.

[0022] Figure 5 This is a schematic diagram of the structure of the field distribution tuning method within the deflection cavity in this invention.

[0023] Figure 6 This is a schematic diagram of a bipolar mode electric field.

[0024] Figure 7 This is a schematic diagram of the peak value of the longitudinal electric field measured and calculated inside the deflection cavity in this invention. Detailed Implementation

[0025] This invention provides a method, apparatus, and readable storage medium for tuning the field distribution of a deflection cavity. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] In the implementation methods and claims, unless otherwise specified in the text, the terms "a," "an," "the," and "the" may also include plural forms. If the embodiments of the present invention involve descriptions of "first," "second," etc., such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0027] It should be further understood that the term "comprising" as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, "connected" or "coupled" as used herein can include wireless connections or wireless coupling. The term "and / or" as used herein includes all or any unit and all combinations of one or more associated listed items.

[0028] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0029] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0030] Deflection cavities are widely used in high-energy physics, primarily for bunch or particle separation, beam length measurement, crab-crossings, X-ray pulse compression, and emittance exchange. The inventors have discovered that current tuning schemes can be mainly divided into two types. One is a nodal-shift based tuning scheme. Specifically, this scheme involves inserting detuning rods into each cavity one by one from the output coupling end cavity, and then tuning the corresponding cavity based on the reflection phase at the grid analyzer. Because it requires inserting detuning rods into the cavities, there is a high risk of scratching the cavities. Furthermore, the position of the detuning rod within the cavity significantly affects the reflection phase displayed on the grid analyzer, but this method cannot visually observe the location of the detuning rod within the sealed cavity, thus the measurement of the reflection phase has a certain degree of inaccuracy. Tuning requires individual measurements and tuning, resulting in a large workload and long tuning time.

[0031] Based on this, tuning based on field distribution measurements was developed, such as... Figure 4As shown, the main method involves using a dielectric sphere that passes sequentially through the cavity along its axis. The electric field strength within the cavity is determined by the perturbation, and the corresponding detuning is calculated for tuning. This method allows for direct tuning by obtaining measurement data at various positions within the cavity through a single measurement. However, due to the presence of various field components along the deflection cavity axis, the field distribution obtained using high-dielectric-constant objects or conductive materials is a composite result of these field distributions. For example, at least a transverse magnetic field and a transverse electric field exist simultaneously along the deflection cavity axis. The dielectric used in this method must only affect the electric field; otherwise, the measurement error will increase. Only using objects with low dielectric constants can potentially mitigate this situation; therefore, glass or ceramic spheres are commonly used for measurement. Furthermore, the dielectric sphere used in this method typically has a low dielectric constant, resulting in smaller perturbations and potentially larger measurement errors. The measured transverse electric field amplitude is determined by the two adjacent cavities, essentially representing the superposition of their detuning. Therefore, the detuning calculated from the measured field cannot yield an accurate tuning value. It is evident that while this method can intuitively and continuously detect the resonance within the deflection cavity, it has high requirements for the spherical medium, and detection based on the transverse electric field will lead to frequency detuning. Furthermore, this scheme will result in unclear tuning values, leading to a decrease in tuning accuracy.

[0032] To resolve this technical issue, please refer to the following: Figure 1 and Figure 4 This invention provides a method for tuning the field distribution of a deflection cavity, the steps of which include: S100: Drive the micro-perturbation body to move along the axial path, and detect and record the axial perturbation at each cavity on the axial path through the micro-perturbation body; Specifically, this invention introduces a perturbation body within the cavity, causing a slight disturbance in the cavity's field distribution, thereby inducing a corresponding change in the resonant frequency, and then calculates the change after the perturbation. The perturbation body can be of any shape. The axial path is located on the central axis of the deflection cavity. When the perturbation body is located inside the deflection cavity in its operating state, and it passes through the cavity sequentially along the axial path, the perturbation at the corresponding cavity position is provided by the combined influence of the transverse magnetic field and the transverse electric field. The axial path is as follows: Figure 5 The solid line position is shown. The perturbation can be characterized by the measured reflection coefficient inside the deflection cavity during the detection process. For example, the reflection coefficient can be characterized by the detected reverse wave inside the deflection cavity, that is, how much of the electromagnetic wave incident on the deflection cavity port is reflected to the corresponding position by the deflection cavity body. The detection results of each position inside the deflection cavity are stored, and the perturbation of this detection is stored as the axis perturbation for subsequent calculations. This parameter can be obtained by analysis by a network analyzer or detected by other instruments, which will not be elaborated here.

[0033] S200: Drive the micro-perturbator to move along the off-axis path, and detect and record the off-axis perturbation at each cavity on the off-axis path through the micro-perturbator; the off-axis path and the axial path are located on the same vertical plane; Specifically, for the perturbation, its trajectory is changed to an off-axis path located in the same vertical plane as the axial path, such as... Figure 5 The position is shown by the dashed line. It should be noted that the parameters of the perturbation on the off-axis path and the perturbation on the axial path are equivalent or completely identical, or the same perturbation can be used for both detections. Preferably, the same perturbation is used for detection to ensure that parameters such as the dielectric constant of the perturbation are constant, and to ensure that the perturbation factors of the perturbation on the transverse electric and magnetic fields are consistent during both detections, preventing them from affecting the detection process. When the perturbation passes through the cavity sequentially on the off-axis path, since the off-axis path deviates from the axis in the vertical direction, the perturbation quantity at the corresponding cavity position is provided by the transverse magnetic field, transverse electric field, and longitudinal electric field. The perturbation quantity detected in this instance is stored as the off-axis perturbation quantity for subsequent calculations. Furthermore, this scheme can use any material to measure perturbations, making it readily available. Compared to current schemes that require perturbations to only affect transverse electric or transverse magnetic fields, this scheme is more widely applicable.

[0034] S300. The longitudinal electric field is calculated based on the axial disturbance and the off-axis disturbance. The axial and off-axis perturbations of each cavity in the deflection cavity are obtained. The axial perturbation is the perturbation detected when the micro-perturbation moves into the cavity along the axial path, and the off-axis perturbation is the perturbation detected when the micro-perturbation moves into the cavity along the off-axis path. The axial perturbation includes a transverse magnetic field and a transverse electric field, while the off-axis perturbation includes a transverse magnetic field, a transverse electric field, and a longitudinal electric field. Since the paths for the two measurements change only in the vertical direction, the influence of the transverse magnetic field and transverse electric field is the same in the two measurements in the near-axial case. Since the off-axis and axial perturbations are known, the longitudinal electric field of the corresponding cavity in the deflection cavity can be calculated using these perturbations.

[0035] S400. The cavity of the deflection cavity is tuned according to the longitudinal electric field.

[0036] Specifically, the main purpose of the tuning process is to correct the frequency of each cavity, ensuring that the phase lead between adjacent cavities matches the theoretical value. Therefore, local reflections are adjusted for each cavity of the deflection cavity to achieve tuning. The actual value of the calculated longitudinal electric field is compared with the ideal value of the tuning target, and feedback control is used to tune the corresponding cavity. Further, after tuning one cavity, the process moves to the next cavity and repeats the tuning steps, adjusting the next cavity until all cavities of the deflection cavity are tuned.

[0037] To facilitate understanding, the tuning method in this invention will be further explained; please refer to the following: Figure 2 , Figure 3 and Figure 4 According to electromagnetic field theory, the ideal deflection cavity should operate in TM11 mode. However, due to the introduction of the beam aperture, the higher-order TE11 mode is generated, causing the deflection cavity to actually operate in the hybrid mode HEM11, which is a mixture of TM11 and TE11.

[0038] Specifically, for the ideal single-cavity chain model, we have:

[0039] Where η is the coupling coefficient in the single-cavity chain model. θ is the single-cavity frequency, and θ is the operating mode of the single-cavity chain model. It is the frequency corresponding to the working mode.

[0040] Accordingly, for the dual-gun chain model, we have:

[0041] Where η1 is the coupling coefficient of the TM mode, and η2 is the coupling coefficient of the generated TE mode. For the single-cavity frequency in TM mode, This refers to the single-cavity frequency in TE mode. The operating frequency curves of the single-cavity chain model and the dual-cavity chain model are shown below. Figure 3 The above, Figure 3 The blue dots represent the operating frequencies corresponding to different modes of the deflection cavity obtained in the CST simulation. Figure 3 As can be seen, the deflection cavity in this invention matches the simulation of the dual-cavity chain model, and the deflection cavity actually works in the hybrid mode HEM11 of TM11 and TE11.

[0042] It should be noted that the deflection cavity in this invention is a bipolar mode deflection cavity, but it can be used for higher-order modes such as quadrupole mode. That is, the number of modes of the deflection cavity used to achieve the deflection cavity field distribution tuning method can be 2.

[0043] In some preferred embodiments, prior to the step of moving the perturbation body along the axial path and detecting and recording the axial perturbation at each cavity along the axial path using the perturbation body, the method further includes: The M100 and network analyzer feed power into the deflection cavity, so that each cavity inside the deflection cavity operates in a stable state; M200: Fix the micro-perturbation body to the traction line, and thread the traction line through the external motor; the external motor is used to drive the traction line and the micro-perturbation body to move linearly relative to the deflection cavity when it is working.

[0044] Specifically, taking the bipolar mode as an example, the field diagram of the bipolar mode is as follows: Figure 6 As shown, other pole numbers can also be used in the system, and no restrictions are placed here. Before starting the measurement, the deflection cavity to be tuned is first placed on the test bench to ensure stable operation of the deflection cavity. At the same time, the perturbation is fixed on a non-conductive wire, which is connected to an external motor through the deflection cavity. The external motor provides the kinetic energy required for the movement of the perturbation.

[0045] In some preferred embodiments, the step of driving the micro-perturbator to move along the axial path and detecting and recording the axial perturbation at each cavity along the axial path through the micro-perturbator includes: S110. Set the perturbation on the axis path; S120. The first perturbationless body reflection coefficient when the perturbation is outside the cavity is detected and recorded by a network analyzer. S130. Drive the micro-perturbation body to move at a constant speed along the axial path by an external motor, and measure the first micro-perturbation body reflection coefficient when micro-perturbation bodies are set in each cavity by a network analyzer. S140. The axial disturbance is obtained based on the difference between the reflection coefficient of the first unperturbed body and the reflection coefficient of the first perturbed body.

[0046] Specifically, the reflection coefficient of the first perturbation-free body when the perturbation is outside the cavity is detected and recorded using a network analyzer to achieve baseline calibration. The minor interference of the traction wire itself on the field is also recorded for data correction. When the perturbation is located on the axial path, the field distribution of the deflection cavity chain is tested using the bead-pull method, at which point:

[0047]

[0048] in, It is the first perturbation reflection coefficient obtained when the cavity contains a perturbation. It is the first perturbation-free reflection coefficient detected when there are no perturbations inside the cavity. It is the shape factor of the perturbation with respect to the transverse electric field. A is the form factor of the perturbation to the transverse magnetic field. e1 and A m The material, size, and shape of the perturbation are calibrated to quantify the perturbation's ability to disturb electric and magnetic fields; these parameters are predetermined. It is the angular frequency, ω=2πf, where f is the operating frequency of the cavity; It is the transverse electric field on the axis. It is the transverse magnetic field on the axis. As can be seen, since there are both transverse electric and transverse magnetic fields, the required tuning amount cannot be directly calculated from the field of a single bead-pull. Therefore, it is necessary to use off-axis detection to cancel out the interference of the transverse electric and transverse magnetic fields.

[0049] Further, the step of driving the micro-perturbator to move along the off-axis path, and detecting and recording the off-axis perturbation at each cavity along the off-axis path through the micro-perturbator; wherein the off-axis path and the axial path are located in the same vertical plane, includes: S210. Fix the perturbation body on an off-axis path, wherein the off-axis path and the axial path are located in the same vertical plane; S220. The reflection coefficient of the second perturbationless body when the perturbation is outside the cavity is detected and recorded by a network analyzer. S230. Drive the micro-perturbation body to move at a constant speed along the off-axis path by an external motor, and measure the reflection coefficient of the second micro-perturbation body when the micro-perturbation body is set in each cavity by a network analyzer. S240. The off-axis disturbance is obtained based on the difference between the reflection coefficient of the second perturbationless body and the reflection coefficient of the second perturbation-bearing body.

[0050] Specifically, to prevent errors in tuning quantity measurement caused by transverse electric and magnetic fields, off-axis measurement in the polarization direction is introduced based on axial measurement. The off-axis path is obtained by offsetting the axial path along the polarization direction, and the off-axis path is parallel to the axial path. That is, when driving the perturbation body to move along the axial path, the traction wire is set on the axis of the deflection cavity using a non-conductive traction wire; when driving the perturbation body to move along the off-axis path, the traction wire is moved as a whole in the polarization direction by a first distance, thus obtaining the off-axis path. Setting the perturbation body and path at the off-axis position, since the off-axis path and the axial path are still located in the same vertical plane, only the vertical height changes. For the perturbation body after the change in vertical height, we have:

[0051]

[0052] in, It is the second perturbation reflection coefficient obtained when the cavity has a perturbation during off-axis measurement. This is the second perturbation-free reflection coefficient detected during off-axis measurement when there are no perturbations inside the cavity. It is the shape factor of the perturbation with respect to the longitudinal electric field. It is the transverse electric field when off-axis. It is the transverse magnetic field when the axis is off-axis. This is the axial field at the off-axis position, also known as the longitudinal electric field. It can be seen that when performing off-axis detection on an off-axis path, the variation of the reflection coefficient with the perturbation is jointly determined by the transverse electric field, transverse magnetic field, and longitudinal electric field within the deflection cavity.

[0053] The step of calculating the longitudinal electric field based on the axial disturbance and the off-axis disturbance includes: S310. For each cavity, read the axial disturbance and off-axis disturbance of each cavity respectively; S320. Based on the difference between the axial disturbance and the off-axis disturbance, the change in reflection coefficient disturbance is obtained. S330. Normalize the change in the reflection coefficient perturbation to obtain the longitudinal electric field.

[0054] The deflection cavity can comprise multiple cavities connected in series. Each cavity includes an input port and an output port. The input port of the cavity on the input side is coupled to the input waveguide, and the output port of the cavity on the output side is coupled to the output waveguide. The output ports of other cavities are coupled to the input ports of their adjacent cavities connected in series. The corresponding axial and off-axis perturbations are then read for each cavity. In the near-axis case, the change in the transverse electric and magnetic fields caused by the movement of the perturbation body from the axial path to the off-axis path is negligible. Therefore:

[0055]

[0056] Substituting this into the off-axis disturbance, we can obtain:

[0057] To eliminate the influence of the transverse electric and magnetic fields on the tuning parameters, the difference between the axis perturbation and the off-axis perturbation is calculated, and then:

[0058] Thus, the relationship between the difference between the axial perturbation and the off-axis perturbation and the longitudinal electric field along the off-axis path can be obtained. Since the reflection coefficients of the first unperturbed body and the first perturbed body are known, the value of the axial perturbation can be calculated. Correspondingly, the off-axis perturbation can also be obtained from the reflection coefficients of the second unperturbed body and the second perturbed body. Consequently, the difference between the axial perturbation and the off-axis perturbation is also a definite value. Therefore, the change in reflection coefficient perturbation can be obtained from the difference between the axial perturbation and the off-axis perturbation. .

[0059] Furthermore, in some preferred embodiments, the step of normalizing the variation in the reflection coefficient perturbation to obtain the longitudinal electric field at each cavity includes: S331. Calculate the square root of the change in the reflection coefficient disturbance to obtain the continuous change value of the longitudinal electric field; S332. Based on the continuously changing value of the longitudinal electric field, the peak value of the field in each cavity is obtained, where the peak value of the field is the longitudinal electric field at each cavity.

[0060] The change in reflection coefficient perturbation refers to the magnitude of the change in reflection coefficient caused by the perturbation body at a certain position within the corresponding cavity unit. This change is proportional to the square of the longitudinal electric field. Therefore, for the longitudinal electric field inside each cavity, we have:

[0061] That is, by directly normalizing the square root of the change in reflection coefficient perturbation, the distribution of the longitudinal electric field inside the cavity can be obtained. This longitudinal electric field distribution value is a relative value, and only the relative value is needed for this calculation. It should be noted that since the diameters of the input and output ports of different cavities are smaller than the maximum diameter of the cavity, the cavities are isolated by protruding cavity walls. Under the action of the cavity walls, the field inside the deflection cavity will undergo periodic fluctuations. Therefore, the change value of the longitudinal electric field is detected and its local maximum value is taken. For example, in some preferred embodiments of the present invention, the longitudinal electric field at 30,000 points is detected and calculated as the micro-perturbation body operates, resulting in the change curves of the longitudinal electric field at each position of the deflection cavity, as shown below. Figure 7 As shown, the local maximum values ​​of the longitudinal electric field circled out are the field peak values ​​in each cavity, and these are used as the longitudinal electric field values ​​inside each cavity. This longitudinal electric field can be directly used for detuning calculation.

[0062] Furthermore, the step of tuning the cavity of the deflection cavity according to the longitudinal electric field includes: S410. Based on the longitudinal electric field, the forward and reverse waves of the cavity are calculated. S420. Calculate the cavity detuning amount of each cavity based on the forward and reverse waves; adjust the cavity resonant frequency according to the cavity detuning amount to tune the cavity of the deflection cavity.

[0063] The structural field within the deflection cavity is formed by the superposition of forward-propagating waves and backward-propagating waves. Therefore, the forward wave in the nth cavity of the deflection cavity... and reverse wave ,have:

[0064]

[0065] Among them, E n For the peak electric field in the nth cavity, i.e., the longitudinal electric field, correspondingly, E n-1 This represents the peak electric field in the (n-1)th cavity, also known as the longitudinal electric field. The intercavity phase shift represents the design of the deflection cavity. and Let be the phase factor, which represents the phase delay of the forward wave or the phase lead of the reverse wave. Then, the detuning of each cavity can be calculated based on the forward wave expression and the reverse wave expression.

[0066] Specifically, the local reflection coefficient of each cavity ,have:

[0067]

[0068] Then we can obtain the formula for calculating the frequency in relation to the forward and reverse waves:

[0069] in, This is the design frequency of the deflection cavity in this invention. The frequency that needs to be tuned, i.e., the detuning amount, and Q0 is the unloaded quality factor of the cavity, can be calculated using the above formula. Therefore, based on the amount of mistuning The shape of the cavity is changed by external force so that its frequency reaches the predetermined ideal design frequency, thus completing the tuning. It should be noted that the precise tuning scheme in this invention takes a bipolar mode as an example, and the deflection cavity has 2 modes. However, it is not limited to this; this scheme can also be applied to higher-order modes, and it is effective for tuning any higher-order mode cavity. It can be used as a universal scheme for tuning higher-order mode cavities.

[0070] Based on the same inventive concept, the present invention also provides a computer device, which includes at least one processor, at least one memory, a communication interface, and a bus; wherein the processor, memory, and communication interface communicate with each other through the bus; the memory stores program instructions executable by the processor, and the processor, when calling the program instructions, implements the deflection cavity field distribution tuning method as described in any one of claims 1-8. Specific details are as described in the above-described specific embodiments of the deflection cavity field distribution tuning method, and will not be repeated here.

[0071] Based on the same inventive concept, the present invention also provides a computer-readable storage medium storing a computer program thereon. When the computer program is executed by a computer processor, it causes the computer to perform the deflection cavity field distribution tuning method described above. Specific details are as described in the specific embodiments of the deflection cavity field distribution tuning method above, and will not be repeated here.

[0072] This invention provides a method, device, and readable storage medium for tuning the field distribution of a deflection cavity. The method includes: driving a micro-perturbation body to move along an axial path, and detecting and recording the axial perturbation at each cavity along the axial path using the micro-perturbation body; driving the micro-perturbation body to move along an off-axis path, and detecting and recording the off-axis perturbation at each cavity along the off-axis path using the micro-perturbation body; the off-axis path and the axial path are located in the same vertical plane; calculating the longitudinal electric field based on the axial perturbation and the off-axis perturbation; and tuning the cavity of the deflection cavity based on the longitudinal electric field. This invention directly tunes the deflection cavity by measuring the longitudinal electric field, preventing errors in the transverse magnetic field and transverse electric field from affecting the tuning effect and improving the tuning accuracy of the deflection cavity.

[0073] Compared to traditional nodal-shift and axial field distribution tuning schemes based on dielectric spheres, this precise tuning scheme offers significant technical advantages and application value. Compared to the nodal-shift scheme, this scheme eliminates the need for a detuning rod inserted into the deflection cavity, fundamentally avoiding the risk of cavity scratches and ensuring the structural integrity of the deflection cavity. The scheme employs a measurement method where a perturbation body traverses the entire cavity chain, eliminating concerns about the perturbation body's position within the cavity affecting the measurement results, effectively improving data accuracy. Furthermore, a single perturbation body traverse completes the measurement of the entire cavity chain and calculates the required tuning amount for each cavity, significantly reducing measurement and calculation time and substantially improving the overall efficiency of the tuning process. In contrast to axial field distribution tuning schemes based on dielectric spheres, this scheme does not require a specific material for the perturbation body; any perturbation body can be used, lowering the tuning threshold and cost. Furthermore, in this invention, the longitudinal electric field is used as the measurement object, and the measurement result is determined only by the frequency of the cavity itself. This allows for direct and accurate determination of the detuning of each cavity, reducing errors in intermediate conversion steps. At the same time, the field distribution and phase data obtained by this method are more stable, providing a better data foundation for the calculation of detuning and exhibiting outstanding advantages in the accuracy of detuning calculation.

[0074] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for tuning the field distribution of a deflection cavity, characterized in that the steps include... include: Drive the perturbation body to move along the axial path, and detect and record the axial perturbation at each cavity along the axial path through the perturbation body; The perturbation body is driven to move along an off-axis path, and the off-axis perturbation at each cavity along the off-axis path is detected and recorded by the perturbation body; the off-axis path and the axial path are located on the same vertical plane; The longitudinal electric field is calculated based on the axial disturbance and the off-axis disturbance. The cavity of the deflection cavity is tuned according to the longitudinal electric field.

2. The deflection cavity field distribution tuning method according to claim 1, characterized in that, The step of driving the micro-perturbator to move along the axial path and detecting and recording the axial perturbation at each cavity along the axial path through the micro-perturbator includes: Set the perturbation on the axis path; The first perturbationless body reflection coefficient when the perturbation is outside the cavity was detected and recorded using a network analyzer. The perturbation body is driven by an external motor to move at a constant speed along the axial path, and the first perturbation body reflection coefficient when the perturbation body is set in each cavity is measured by a network analyzer. The axial disturbance is obtained based on the difference between the reflection coefficient of the first unperturbed body and the reflection coefficient of the first perturbed body.

3. The deflection cavity field distribution tuning method according to claim 1, characterized in that, The driver moves the micro-perturbation body along the off-axis path, and detects and records the off-axis perturbation at each cavity along the off-axis path through the micro-perturbation body. The steps to obtain the off-axis path and the axial path being located in the same vertical plane include: The perturbation body is fixed on an off-axis path, wherein the off-axis path and the axial path are located in the same vertical plane; The reflection coefficient of the second perturbationless body when the perturbation is outside the cavity is detected and recorded using a network analyzer. The perturbation is driven by an external motor to move at a constant speed along an off-axis path, and the reflection coefficient of the second perturbation when the perturbation is set in each cavity is measured by a network analyzer. The off-axis perturbation is obtained from the difference between the reflection coefficient of the second perturbationless body and the reflection coefficient of the second perturbation-bearing body.

4. The deflection cavity field distribution tuning method according to claim 3, characterized in that, The off-axis path is obtained by offsetting the axial path along the polarization direction, and the off-axis path is parallel to the axial path.

5. The method for tuning the field distribution of the deflection cavity according to claim 1, characterized in that, The steps for calculating the longitudinal electric field based on the axial perturbation and the off-axis perturbation include: For each cavity, the axial disturbance and off-axis disturbance of each cavity are read separately; The change in reflection coefficient is obtained based on the difference between the axial disturbance and the off-axis disturbance. The longitudinal electric field at each cavity is obtained by normalizing the change in the reflection coefficient perturbation.

6. The method for tuning the field distribution of the deflection cavity according to claim 5, characterized in that, The step of normalizing the change in the reflection coefficient perturbation to obtain the longitudinal electric field at each cavity includes: Calculate the square root of the change in the reflection coefficient disturbance to obtain the continuous change value of the longitudinal electric field; Based on the continuously changing value of the longitudinal electric field, the peak value of the field in each cavity is obtained, and the peak value of the field is the longitudinal electric field at each cavity.

7. The method for tuning the field distribution of the deflection cavity according to claim 1, characterized in that, The step of tuning the cavity of the deflection cavity according to the longitudinal electric field includes: Based on the longitudinal electric field, the forward and reverse waves of the cavity are calculated; Based on the forward and reverse waves, the cavity detuning of each cavity is calculated; the cavity resonant frequency is adjusted according to the cavity detuning to tune the cavity of the deflection cavity.

8. The method for tuning the field distribution of the deflection cavity according to claim 1, characterized in that, The deflection cavity has 2 modes.

9. A computer device, characterized in that, It includes at least one processor, at least one memory, a communication interface, and a bus; wherein, The processor, memory, and communication interface communicate with each other through the bus; the memory stores program instructions that can be executed by the processor, and when the processor calls the program instructions, it implements the deflection cavity field distribution tuning method as described in any one of claims 1-8.

10. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed, causes the computer device to perform the deflection cavity field distribution tuning method as described in any one of claims 1-8.

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