Beam synchronous phase online measurement method, device and equipment based on virtual open loop technology and medium

Abstract

This invention discloses a method, apparatus, device, and medium for online beam synchronization phase measurement based on virtual open-loop technology, comprising: obtaining the original cavity pressure and original forward voltage of the radio frequency cavity and performing calibration and normalization processing to obtain the cavity pressure. V C and forward voltage V F Based on cavity pressure V C and forward voltage V F Establish the cavity differential equation; calculate the steady-state detuning Δ based on the cavity differential equation. oh Based on steady-state detuning Δ oh And based on the cavity pressure when there is no beam. V C and forward voltage V F The cavity pressure change under the combined effects of the beam current and the radio frequency loop was calculated during closed-loop operation. v c and forward voltage change v f Establish a small-signal differential equation; based on the small-signal differential equation, solve for the loop driving term. u Caused cavity pressure changes v cf Based on cavity pressure changes v c and cavity pressure changes v cf The cavity pressure change under beam term excitation alone was obtained. v vcb And reconstruct the cavity pressure including beam loading effect under the "virtual open-loop" condition. V C，VOL Based on cavity pressure V C,VOL phase ∠ V C,VOL Calculate the beam phase.

Description

Technical Field

[0001] This invention relates to the field of particle accelerators, and more specifically to a method, apparatus, equipment, and medium for online beam synchronization phase measurement based on virtual open-loop technology. Background Technology

[0002] In a particle accelerator, the energy gain obtained by a beam passing through a radio frequency cavity can be characterized as the accelerating cavity pressure. V acc ,satisfy V acc = V c ·cos( ),in, V c For radio frequency cavity pressure, For beam and V c The phase between beam phases is crucial. To achieve the desired energy gain and longitudinal stability of the beam, accurate beam synchronization phase is essential. In engineering, a "phasescan" procedure is commonly used to calibrate the beam synchronization phase offline / quasi-online before beam connection. However, environmental factors (temperature, humidity, etc.) introduce phase drift, causing the calibrated beam synchronization phase to deviate from its optimal state over time, requiring periodic phase scans to restore accuracy. Modern large-scale installations often contain dozens to thousands of cavities; repeated phase scans significantly consume machine time, reduce availability, and rely on high-performance beam diagnostics (BPM / BCM, etc.) to form a closed-loop evidence chain. However, these instruments are expensive and difficult to deploy comprehensively near every cavity, further increasing deployment costs.

[0003] To reduce machine time consumption, advanced laboratories abroad have recently proposed a beam phase measurement approach based on the transient beam loading effect: when the beam enters the cavity, it exchanges energy with the cavity field, causing transient changes in the cavity field; by modeling and inverting the transient response of the probe / reflection channel, the beam synchronization phase can be estimated without performing traditional phase scanning. This approach has advantages such as saving machine time, having the potential for online operation, and being insensitive to long-term environmental drift, and has been verified in some light source / free-electron laser devices.

[0004] To improve the discernibility of transient changes, existing technologies typically require the RF cavity to operate in open-loop mode. In this mode, transient changes in the cavity pressure signal are only caused by the beam load, thus avoiding cavity field changes caused by the RF loop. However, in high-beam scenarios such as proton linear accelerators and high-intensity heavy-ion linear accelerators, amplitude and phase disturbances and link instability during open-loop operation increase the risk of beam loss, potentially leading to beam drop or interlocking in extreme cases, which is unacceptable in engineering. In the closed-loop direction, existing research has proposed using the closed-loop delay window and steady-state forward voltage for beam phase measurement, achieving beam phase measurement in closed-loop mode. However, due to limitations in measurement link non-ideals and noise handling, as well as the robustness of feedforward control (such as iterative learning feedforward), these approaches still have room for improvement in measurement accuracy and flexibility. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, in response to the above-mentioned problem, the objective of the present invention is to provide a method, apparatus, device, and medium for online beam synchronization phase measurement based on virtual open-loop technology, which enables the radio frequency loop to be in an equivalent open-loop state, thereby extracting beam synchronization phase information in real time while ensuring stable closed-loop operation.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0007] In a first aspect, the present invention provides a method for online beam synchronization phase measurement based on virtual open-loop technology, comprising:

[0008] The original cavity pressure and original forward voltage of the RF cavity are obtained, and then calibrated and normalized to obtain the cavity pressure. V C and forward voltage V F ;

[0009] Based on cavity pressure V C and forward voltage V F Establish the cavity differential equation;

[0010] Calculation of steady-state detuning Δ based on cavity differential equation ω ;

[0011] Based on steady-state detuning Δ ω And based on the cavity pressure when there is no beam. V C and forward voltage V F The cavity pressure change under the combined effects of the beam current and the radio frequency loop was calculated during closed-loop operation. v c and forward voltage change vf Establish small-signal differential equations;

[0012] Solving the loop driving term based on small-signal differential equations u Caused cavity pressure changes v cf ;

[0013] Based on cavity pressure changes v c and cavity pressure changes v cf The cavity pressure change under beam term excitation alone was obtained. v vcb And reconstruct the cavity pressure including beam loading effect under the "virtual open-loop" condition. V C，VOL ;

[0014] Based on cavity pressure V C, VOL phase ∠ V C, VOL Calculate beam phase .

[0015] In some possible implementations, based on cavity pressure V C and forward voltage V F The differential equation for the cavity is established as follows:

[0016] ;

[0017] in, V C0 and V C1 cavity pressures under no-beam and with-beam conditions, respectively. V C , V F0 and V F1 Forward voltages under no-current and with-current conditions, respectively. V F , V b The beam current equivalent voltage, Δ ω and ω 0.5 These represent the cavity detuning and half-bandwidth, respectively. β The coupling coefficient is... t For time, j It is the imaginary unit.

[0018] In some possible implementations, steady-state detuning Δ ω The calculation formula is:

[0019] ;

[0020] in, V F,ss This represents the steady-state value of the forward voltage before the beam arrives. for V F,ss The phase.

[0021] In some possible implementations, based on steady-state detuning Δ ω And based on the cavity pressure when there is no beam. V C and forward voltage V F The cavity pressure change under the combined effects of the beam current and the radio frequency loop was calculated during closed-loop operation. v c and forward voltage change v f Establish the small-signal differential equation:

[0022] .

[0023] In some possible implementations, the loop driving term is solved based on the small-signal differential equation. u Caused cavity pressure changes v cf ,include:

[0024] The small-signal differential equation is transformed into a difference equation, and the sampling points are... n The differential part d v cf / dt is represented by the difference between two adjacent sampling points:

[0025] ;

[0026] Substituting the above equation into the small-signal differential equation and simplifying, we get:

[0027] ;

[0028] Expanding the above equation using the real and imaginary parts, we get:

[0029] ;

[0030] in, v cf,i and v cf,q Corresponding to v cf The real and imaginary parts; u i and u q Corresponding to u The real and imaginary parts,T s The sampling period of the voltage signal;

[0031] The loop driving term is obtained by solving the above difference equation. u cavity pressure changes caused by individual excitation v cf .

[0032] In some possible implementations, based on changes in cavity pressure v c and cavity pressure changes v cf The cavity pressure change under beam term excitation alone was obtained. v vcb And reconstruct the cavity pressure including beam loading effect under the "virtual open-loop" condition. V C，VOL The process is as follows:

[0033] From changes in cavity pressure v c Subtracting cavity pressure changes v cf The cavity pressure change caused by the beam term was obtained. v vcb ;

[0034] Changes in cavity pressure v vcb The cavity pressure when there is no current is superimposed. V C0 Reconstruct the cavity pressure containing only the beam term V C, VOL :

[0035] .

[0036] In some possible implementations, the beam phase The calculation formula is:

[0037] .

[0038] Secondly, the present invention also discloses an online beam synchronization phase measurement device based on virtual open-loop technology, comprising:

[0039] The signal acquisition unit is configured to obtain the raw cavity pressure of the radio frequency cavity. V c * and the original forward voltage V f * The cavity pressure was obtained by calibration and normalization. V C and forward voltage V F ;

[0040] The cavity differential equation building unit is configured to be based on cavity pressure. V C and forward voltage V F Establish the cavity differential equation;

[0041] The steady-state detuning establishment unit is configured to calculate the steady-state detuning Δ based on the cavity differential equation. ω ;

[0042] The small-signal differential equation establishment unit is configured based on steady-state detuning Δ ω And based on the cavity pressure when there is no beam. V C and forward voltage V F The cavity pressure change under the combined effects of the beam current and the radio frequency loop was calculated during closed-loop operation. v c and forward voltage change v f Establish small-signal differential equations;

[0043] The cavity pressure variation solution unit is configured to solve the loop driving term based on small-signal differential equations. u Caused cavity pressure changes v cf ;

[0044] The cavity pressure solving element is configured to be based on cavity pressure variations. v c and cavity pressure changes v cf The cavity pressure change under beam term excitation alone was obtained. v vcb And reconstruct the cavity pressure including beam loading effect under the "virtual open-loop" condition. V C, VOL ;

[0045] The beam phase solving unit is configured to be based on cavity pressure. V C, VOL phase ∠ V C, VOL Calculate beam phase .

[0046] Thirdly, the present invention also provides an electronic device, comprising: at least one processor; and a memory communicatively connected to the processor; wherein the memory stores instructions executable by the processor, the instructions being executed by the processor to enable the processor to perform the method described thereon.

[0047] Fourthly, the present invention also provides a computer-readable storage medium for storing one or more programs, characterized in that the one or more programs include computer instructions for causing a computer to perform the method.

[0048] Because the present invention adopts the above technical solution, it has the following characteristics:

[0049] 1. Precise measurement of beam synchronization phase: This invention can directly solve the phase of the beam relative to the cavity pressure, i.e., the beam synchronization phase, effectively avoiding phase drift caused by environmental factors, thereby ensuring high accuracy of the calculation results.

[0050] 2. High-precision calculation in closed-loop mode: This invention can calculate the beam phase in closed-loop mode, and its calibration time window is... T w Unaffected by loop delay τ d The limitations of this system allow for improved measurement accuracy by fitting more sampling points, thereby further enhancing the system's stability and reliability.

[0051] 3. Enhanced flexibility and compatibility: Since the forward voltage signal does not require a steady state, the present invention has lower requirements for beam feedforward compensation, and has higher flexibility under different operating conditions, making it adaptable to a wider range of application scenarios.

[0052] In summary, this invention can operate directly in normal operation, reducing reliance on expensive beam-guided equipment. It is of great significance for improving accelerator availability, reducing operating costs, and promoting the widespread application of particle accelerators. It can be widely used in particle accelerators. Attached Figure Description

[0053] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. In the drawings:

[0054] Figure 1 This is a flowchart of the online beam synchronization phase measurement method according to an embodiment of the present invention.

[0055] Figure 2 This is a structural diagram of the online beam synchronization phase measurement system according to an embodiment of the present invention.

[0056] Figure 3This is a schematic diagram illustrating the measurement principle of beam phase in the open-loop operation mode of the RF cavity according to an embodiment of the present invention. In this diagram, a represents the transient beam load effect caused by the beam in the open-loop mode, and b represents the cavity pressure change caused by the beam during the open-loop operation of the RF cavity within the flat-top time, i.e., the beam load signal. V cb c is the IQ coordinate graph of cavity pressure change.

[0057] Figure 4 The diagram shows the voltage of the radio frequency cavity in open-loop operation mode as measured in an embodiment of the present invention. In this diagram, a represents the cavity voltage with current (red) and without current (blue) and the corresponding forward voltage (green) in open-loop operation mode of the radio frequency cavity; b is a magnified detail of the gray rectangular area in a; and c is the I / Q coordinate diagram corresponding to the cavity voltage signal in b.

[0058] Figure 5 This is a schematic diagram of the virtual open-loop technology according to an embodiment of the present invention.

[0059] Figure 6 The figures shown are measured results of signals at various important nodes in the virtual open-loop technology of this invention. In figure a, the waveforms of cavity pressure and forward voltage with and without beam current during closed-loop operation of the RF cavity in this invention are shown, with the upper sub-figure corresponding to the real part and the lower sub-figure corresponding to the imaginary part; figure b shows the measured small signal (…) in this invention. v c and v f ) and RF loop response ( v cf The waveform diagram is shown, with the upper sub-diagram corresponding to the real part and the lower sub-diagram corresponding to the imaginary part; c is the beam load signal under virtual open-loop conditions reconstructed by the embodiments of the present invention. V C, VOL Compared with the measured open-loop beam load signal V cb The comparison diagram shows the real part at the top and the imaginary part at the bottom.

[0060] Figure 7 The following are measurement results for open-loop, closed-loop, and virtual open-loop operation of the RF cavity in this embodiment of the invention. In the first two sub-figures, a) the complete cavity pressure pulse signal is shown, with the upper sub-figure corresponding to the amplitude and the lower sub-figure corresponding to the phase. In the second two sub-figures, b) the detailed images of the beam load signal after amplification are shown, with the upper sub-figure corresponding to the amplitude and the lower sub-figure corresponding to the phase. The IQ coordinate graph in the third figure compares the beam load signal vector diagrams under the three conditions (open-loop, closed-loop, and virtual open-loop).

[0061] Figure 8The figures show the beam load IQ coordinates of the measured RF cavity under open-loop (green), closed-loop (blue), and virtual open-loop (red) conditions in this embodiment of the invention. Figure a corresponds to the measurement results under four conditions: beam current intensity of 60 mA, beam phase of -90°, -45°, -19°, and 0°; figure b corresponds to the measurement results under four conditions: beam current intensity of 5 mA, beam phase of -90°, -45°, -19°, and 0°.

[0062] Figure 9 This is a comparison of the measured beam phase under different current intensities in the embodiments of the present invention with the measured BPM (green) measurement results under closed-loop (blue) and virtual open-loop (red) conditions. Among them, Figure a corresponds to the comparison of the beam phase measurement results at -87 degrees (current intensity equal to 5 mA), and Figure b corresponds to the comparison of the beam phase measurement results at -42 degrees (current intensity equal to 5 mA).

[0063] Figure 10 This is a structural diagram of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0064] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0065] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0066] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "above," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure.

[0067] To address the beam loss risks and application limitations caused by the open-loop operation required by traditional methods, this invention provides a method, apparatus, device, and medium for online beam synchronization phase measurement based on virtual open-loop technology, including: obtaining the original cavity pressure of the radio frequency cavity. V c * and the original forward voltage V f * The cavity pressure is obtained through processing. V C and forward voltage V F Based on cavity pressure V C and forward voltage V F Establish the cavity differential equation; calculate the steady-state detuning Δ based on the cavity differential equation. ω Based on steady-state detuning Δ ω And based on the cavity pressure when there is no beam. V C and forward voltage V F The cavity pressure change under the combined effects of the beam current and the radio frequency loop was calculated during closed-loop operation. v c and forward voltage change v f Establish a small-signal differential equation; based on the small-signal differential equation, solve for the loop driving term. u Caused cavity pressure changes v cf Based on cavity pressure changes v c and cavity pressure changes v cf The cavity pressure change under beam term excitation alone was obtained. v vcb And reconstruct the cavity pressure including beam loading effect under the "virtual open-loop" condition. V C, VOL ; for cavity pressure V C, VOL obtain the phase ∠ by performing linear fitting. V C, VOL And calculate the beam phase Therefore, this invention can separate the cavity field changes caused by the beam and the feedback loop in the closed-loop operation mode of the RF cavity, making the RF loop in an equivalent open-loop state (the RF cavity still operates in a closed loop, but the measurement results are not affected by the closed loop and can be approximated as open-loop operation). This allows for real-time extraction of beam synchronization phase information while ensuring stable closed-loop operation. This invention can directly solve for the phase of the beam relative to the cavity pressure, and the calculation results are no longer affected by phase drift caused by environmental factors, nor are they limited by the closed-loop delay.

[0068] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0069] Example 1: As Figure 1 As shown, the online beam synchronization phase measurement method based on virtual open-loop technology provided in this embodiment includes:

[0070] S1, Baseband signal reading.

[0071] In this embodiment, the cavity sampling signal of the radio frequency cavity is measured online. P t Cavity incident signal P f and cavity reflection signal P r Obtain the raw cavity pressure of the radio frequency cavity V c * Original forward voltage V f * and the original reverse voltage V r * .

[0072] Specifically, such as Figure 2 As shown, this embodiment includes an online beam synchronization phase measurement system, comprising a digital low-level system 1, a solid-state power source 2, a directional coupler 3, an input coupler 4, an RF cavity 5, a signal extraction coupler 6, a down-conversion module 7, and a host computer 8. The output of the digital low-level system 1 is connected to the input of the solid-state power source 2. The output of the solid-state power source 2 is connected to the input of the directional coupler 3. The output of the directional coupler 3 is fed into the RF cavity 5 via the input coupler 4. The directional coupler 3 is used to extract the cavity incident signal from the RF cavity 5. P f and cavity reflection signals Pr The signal extraction coupler 6 is connected to the radio frequency cavity 5 for extracting the cavity sampling signal. P t Cavity incident signal P f Cavity reflection signal P r and cavity sampling signal P t After being down-converted by the down-conversion module 7, the signal is sent to the digital low-level system 1. The digital low-level system 1 is based on the cavity incident signal. P f Cavity reflection signal P r and cavity sampling signal P t The corresponding digital baseband in-phase quadrature (I / Q) components are demodulated and uploaded to the host computer 8 via the data bus.

[0073] Furthermore, the digital low-level system 1 includes an FPGA, which contains a digital signal processing module. The digital signal processing module samples the cavity signal from the radio frequency cavity 5. P t Cavity incident signal P f and reflected signals P r The processing yields the corresponding three raw voltage signals, including the raw cavity pressure. V c * Original forward voltage V f * and the original reverse voltage V r * It should be noted that the parameters involved in this embodiment, for example... V c * , V f * , V C , V F , V cb and V b Both are in complex form, and can be expressed as amplitude and phase, for example: V =| V | e j∠V , among which, | V | represents the amplitude or modulus, ∠ VThis refers to the phase, also known as the argument; it can also be expressed as the real part plus the imaginary part, for example: V = V I + jV Q ,in, V I The real part, also known as the in-phase component, V Q It is the imaginary part, or orthogonal component.

[0074] Furthermore, for cross-validation, a beam current detector (BCM) 9 can be installed at the entrance of the RF cavity 5 to measure the beam current intensity online; a beam position detector (BPM) 10 can also be installed at the exit of the RF cavity 5 to measure the phase of the beam online.

[0075] S2, Signal calibration and normalization.

[0076] In this embodiment, based on the original cavity pressure V c * and forward voltage V f * The cavity pressure was obtained after calibration and normalization. V C and forward voltage V F .

[0077] Forward voltage V f * Calibration is performed using V f, cali = XV f * Obtain the calibrated forward voltage V f, cali Among them, the correction coefficient X For complex numbers, the correction coefficient is... X It can be solved using existing techniques, and can be expressed as amplitude and phase (i.e. X =| X | e j∠X The form can also be represented as the real part plus the imaginary part (i.e., ...). X = X I + jX Q The form of the signal is not limited here; what needs to be noted is the original signal. V c * It is typically used as a reference signal and requires no calibration.

[0078] Furthermore, such as Figure 3 As shown in a, the original cavity pressure V c * After a fill time (the time it takes for the RF cavity voltage to reach a steady state from 0), it reaches a steady state. The steady-state cavity voltage will be maintained for a period of time for beam acceleration (flat-top time). The flat-top time is calculated... t 1 and t The average cavity pressure between two time points is the normalization coefficient. V c, ss * The calculation formula is as follows:

[0079]

[0080] The mean function is used to calculate the average value, and it can be implemented using numpy.mean in Python.

[0081] Based on the original cavity pressure V c * use V C = V c * / V c, ss * Obtain the normalized cavity pressure V C After normalization V C The steady-state amplitude is 1 and the phase is 0 degrees. Similarly, to ensure signal consistency, the calibrated forward voltage must be... V f, cali The normalized forward voltage is obtained by performing a completely consistent scaling process. V F ,Right now V F = V f, cali / V c, ss * .

[0082] S3. Establish the differential equation.

[0083] In this embodiment, based on cavity pressure V C and forward voltage V F Establish the cavity differential equation:

[0084]

[0085] In the formula,V C0 and V C1 cavity pressures under no-beam and with-beam conditions, respectively. V C , V F0 and V F1 Forward voltages under no-current and with-current conditions, respectively. V F , β The coupling coefficient is... V b The beam current equivalent voltage; Δ ω and ω 0.5 These are the cavity detuning and half-bandwidth, respectively. Under the premise that the beam is a short pulse (e.g., the width of the beam pulse is less than 100 microseconds), they can be approximately considered to be unaffected by the beam.

[0086] S4. Steady-state detuning calculation.

[0087] In this embodiment, steady-state detuning calculation refers to calculating the cavity pressure. V C Forward voltage V F The steady-state average value is obtained, and the detuning angle Δ under steady state is calculated. θ and detuning Δ ω Normally, ω 0.5 Given that Δ ω The detuning angle Δ can be obtained when there is no beam. θ The steady-state value is obtained by calculation using the following formula:

[0088]

[0089] in, V F,ss This represents the steady-state value of the forward voltage signal before the beam arrives. V F,ss The calculation formula is:

[0090]

[0091] in, Given a time interval, using Δ θ =-∠ V F,ss Calculate the detuning angle under steady state and obtain the steady-state detuning Δ according to formula (2). ω .

[0092] S5. Establish the small-signal differential equation.

[0093] In this embodiment, the cavity pressure is determined based on whether there is a beam or not. V C ( V C1 and V C0 and forward voltage V F ( V F1 and V F0 The cavity pressure change under the combined effects of the beam current and the radio frequency loop was calculated during closed-loop operation. v c and forward voltage change v f And establish small-signal differential equations.

[0094] like Figure 5 As shown, the cavity pressure varies depending on whether there is a beam or not. V C ( V C1 and V C0 Forward voltage V F ( V F1 and V F0 The cavity pressure change under the combined effects of the beam current and the radio frequency loop was calculated during closed-loop operation. v c and forward voltage change v f The formula is as follows:

[0095]

[0096] Based on small signal v c and v f (In this embodiment, the small signal refers to the signal generated by the beam itself and the control loop when the beam passes through the flat-top region of the radio frequency pulse, and is superimposed on the beamless cavity pressure.) V C0 and forward voltage V F0 In this embodiment, the smaller signals are uniformly represented by lowercase letters, such as... v c , v f , v vcb (etc.). By subtracting the differential equation without a current from the differential equation with current, we obtain the small-signal differential equation:

[0097]

[0098] The input terms on the right side of the above differential equation (3) consist of two parts: the first part is the RF loop drive term, representing the forward voltage term changed by adjusting the RF power source; the second part is the beam current term. v c This represents the cavity pressure change caused by the combined effects of the RF loop driving term and the beam term.

[0099] Since equation (3) above is a linear equation, let's assume that the cavity pressure changes caused by the beam current and the radio frequency loop are respectively denoted as... v vcb and v cf The two together form v c ,Right now v c = v vcb + v cf Then the above equation (3) can be decomposed into:

[0100]

[0101] And order u =2 βv f / (1+ β The differential equation under the action of the radio frequency loop term is obtained as follows:

[0102]

[0103] in, v cf For loop drive items u The resulting changes in cavity pressure.

[0104] S6. Solve for cavity pressure changes v cf .

[0105] In this embodiment, the cavity pressure change is solved. v cf That is, solving the response of the difference equation under the sole excitation of the loop driving term. v cf The specific process is as follows:

[0106] Transform the above differential equation (4) into a difference equation: sampling point n The differential part d v cf / dt can be based on two adjacent sampling points ( n and n The difference representation of +1):

[0107]

[0108] Substituting the above equation into formula (4) and simplifying, we get:

[0109]

[0110] Furthermore, expanding the above equation according to its real and imaginary parts, we get:

[0111]

[0112] in, v cf,i and v cf,q Corresponding to v cf The real and imaginary parts; u i and u q Corresponding to u The real and imaginary parts. T s For voltage signals (such as) v cf and u The sampling period.

[0113] By solving the difference equation (5) above, the loop driving term can be obtained. u cavity pressure changes caused by individual excitation v cf .

[0114] S7. Calculate the virtual open-loop signal V C, VOL and beam phase .

[0115] In this embodiment, the change in cavity pressure v c deducting from v cf The influence of the beam term alone was used to obtain the cavity pressure change. v vcb Based on this, the cavity pressure signal including the beam load effect under the "virtual open loop" is reconstructed. V C, VOL ,right V C, VOL Linear fitting to obtain phase ∠ V C, VOL And convert the beam phase to obtain the beam phase. The specific process is as follows:

[0116] Since differential equation (3) is a linear equation, from v cdeducting from v cf The cavity pressure change caused by the beam term can then be obtained. v vcb .exist v vcb The cavity pressure when there is no current is superimposed. V C0 This means that the cavity pressure signal containing only the beam term (excluding the loop drive term) can be reconstructed. V C, VOL ,at this time V C, VOL Since the contribution from the RF loop is no longer included, it can be considered as the cavity pressure signal caused by the beam under "virtual open-loop" conditions. The formula for the above process is described as follows:

[0117] ;

[0118] Among them, the virtual open-loop cavity pressure signal V C, VOL The letter V in the subscript stands for "Virtual" and OL stands for "Open Loop".

[0119] Furthermore, based on virtual open-loop signals V C, VOL Calculate beam phase :

[0120] .

[0121] The application and verification process of the beam synchronization phase online measurement method based on virtual open-loop technology of the present invention are described in detail below through specific embodiments.

[0122] The online beam synchronization phase measurement method based on virtual open-loop technology provided in this embodiment includes:

[0123] 1. Measure the original cavity pressure of radio frequency cavity 5 V c * Forward voltage V f * and reverse voltage V r * .

[0124] like Figure 2 As shown, the output of the digital low-level system 1 is connected to the input of the solid-state power source 2, the output of the solid-state power source 2 is connected to the input of the directional coupler 3, and the output of the directional coupler 3 is fed into the RF cavity 5 via the input coupler 4. The measurement process is as follows:

[0125] 1. Use signal extraction coupler 6 to extract cavity pressure signal online. P t The incident signal from the cavity was measured online using directional coupler 3. P f and reflected signals P r In this embodiment, the cavity pressure signal P t Cavity incident signal P f and reflected signals P r All are 352.21 MHz radio frequency signals.

[0126] 2. After sequentially down-converting, digitizing, and demodulating the above radio frequency signal using IQ modulation, the original digitized baseband voltage signal, i.e., the original cavity voltage, is obtained in the digitized low-level system 1. V c * Original forward voltage V f * and the original reverse voltage V r * The digital low-level system 1 uploads the aforementioned baseband signal to the data bus.

[0127] II. Signal calibration and normalization.

[0128] Based on the original cavity pressure V c * and original forward voltage V f * The signal calibration and normalization are implemented within the host computer 8, including:

[0129] 1. Original forward voltage signal V f * Calibration.

[0130] The host computer 8 reads the current raw chamber pressure online from the data bus. V c * and original forward voltage V f * First, according to V f, cali = XV f * To solve for the calibrated forward signal, the complex multiplication operation can be performed as follows:

[0131]

[0132] In the formula, V f, caliI and V f, caliQ They are respectively V f, cali The real and imaginary parts; V fI * and V fQ * They are respectively V f * The real and imaginary parts; X I and X Q Calibration coefficients X The real and imaginary parts.

[0133] 2. Normalized original cavity pressure V c * and original forward voltage V f * .

[0134] like Figure 4 As shown in Figure a, after a certain filling time, the original cavity pressure of the RF cavity... V c * exist t =Reaching steady state in 100 microseconds. For example... Figure 4 As shown in b, the beam arrives at 177 microseconds, lasts for 5 microseconds, and ends at 182 microseconds. The cavity pressure during beam passage... V c This causes instantaneous fluctuations. For example... Figure 3 As shown in Figure a, two points are selected before the beam arrives. t 1 and t 2. Calculation V c * exist t 1 and t The average between 2 V c,ss * ,Right now V c,ss * =mean( V c * | t1→t2 Note that, to ensure calculation accuracy, t 1 and t The interval between 2s must be greater than 20 microseconds. t1 must be selected after the cavity pressure reaches steady state, for example: t 1 can be selected from a value between 100 and 156 microseconds. t 2 can be selected as 176 microseconds. Taking this as an example, but not limited to this, the process of calculating the average can be directly called using Python. numpy.mean function.

[0135] The original cavity pressure was respectively... V c * and original forward voltage V f * Normalize:

[0136]

[0137] Among them, the normalized cavity pressure V c The steady-state value is 1+0 j .

[0138] III. Steady-state detuning calculation.

[0139] Calculate the forward voltage signal under both current-free and current-without conditions. V F ( t )exist t 1 and t The steady-state vector is obtained by averaging the values ​​between 2. V F,ss Using np.angle( V F,ss )Calculated V F The phase, further, according to formula (2), yields the steady-state detuning Δ ω .

[0140] IV. Calculation of small signals caused by beam current in closed loop

[0141] like Figure 5 As shown, the cavity pressure varies depending on whether there is a beam or not. V C ( V C1 and V C0 Forward voltage V F ( V F1 and V F0 The cavity pressure change under the combined effects of the beam current and the radio frequency loop was calculated during closed-loop operation. v c and forward voltage changev f The formula is as follows:

[0142]

[0143] Note that since the signals described above are all complex signals, the operations described also follow the rules of complex number arithmetic. Furthermore, a loop driving term is constructed. u =2 βv f / (1+ β Small-signal equation under individual excitation:

[0144]

[0145] V. Solving for changes in cavity pressure v cf .

[0146]

[0147] in, v cf,i , v cf,q initial value v cf,i (1) and v cf,q (1) It can be set to 0; v cf,i ( n )and v cf,q ( n )exist n Values ​​greater than 1 can be obtained by recursively applying the formula above.

[0148] The calculation process is illustrated below: Assume T s ω 0.5 It equals 0.1. T s Δ ω =0.1, the first two sets of values ​​for the loop driving term are 0.1. u i (1)=1; u q (1) = 0; u i (2) = 1.5; u q (2) = 0. Therefore... v cf The calculation process for (2) is as follows:

[0149]

[0150] Substitutev cf,i (1) = 0, v cf,q (1) = 0 and u i (1) = 1; u q (1) = 0, therefore: v cf,i (2) = 0.1 and v cf,q (2) = 0;

[0151] Furthermore, v cf The calculation process for (3) is as follows:

[0152]

[0153] Substitute v cf,i (2) = 0.1, v cf,q (2) = 0 and u i (2) = 1.5; u q (2) = 0, therefore: v cf,i (3) = 0.24 and v cf,q (3) = 0.01; and so on, to obtain all sampling points. n of v cf ( n ).

[0154] VI. Calculate the virtual open-loop signal V C, VOL and beam phase .

[0155] In this embodiment, the loop driving term is obtained. u Response under individual stimulus v cf Afterwards, from v c deducting from v cf The contribution of the beam term alone can be used to obtain the cavity pressure change under beam term excitation. v vcb The calculation formula is:

[0156] ;

[0157] Furthermore, a beam load signal under a virtual open-loop configuration can be constructed. V C, VOL :

[0158] ;

[0159] Note that since the above signals are all complex signals, the above operations also follow the rules of complex number operations.

[0160] Furthermore, such as Figure 8 and Figure 9 As shown, draw on the IQ plane V C, VOL The trajectory of the beam as it passes through (is a straight line), and by performing a linear fit on the trajectory, can be obtained. V C, VOL The phase of the vector ∠ V C, VOL When selecting the linear fitting time window T w At that time, it is necessary to ensure T w Smaller than the width of the beam pulse b w . T w The meaning is as follows Figure 4 As shown in c, the overall pulse width of the beam b w The initial fitting window is 5 microseconds (from 177 microseconds to 182 microseconds); however, for linear fitting, a 4-microsecond fitting window (from 177 microseconds to 181 microseconds) can be selected. In this embodiment, to ensure sufficient fitting accuracy, it is recommended that... T w The parameter space is: 3 microseconds. T w < b w In existing closed-loop based measurement methods, due to loop delay... τ d (Typical value: 1-1.5 microseconds) limitation, T w The maximum selectable time is 1.5 microseconds, which significantly compresses the number of effective sampling points available for fitting, thereby reducing measurement accuracy. Figure 9 As shown. Finally, ∠ is obtained through linear fitting. V C, VOL The beam phase can be calculated using the following formula. :

[0161] .

[0162] VII. Online Experimental Verification

[0163] The experiments in this embodiment have been verified at the European Spallation Neutron Source (Lund, Sweden). Figure 2As shown, a beam current detector (BCM) 9 is installed upstream of the RF cavity 5 for online measurement of beam current; a beam position detector (BPM) 10 is installed downstream of the RF cavity 5 for online measurement of beam phase. Furthermore, the beam current and phase calculated in this embodiment are compared with the measured values ​​of the BCM and BPM.

[0164] like Figure 7 As shown, the present invention demonstrates measurement comparison and consistency verification under three conditions: open-loop, closed-loop, and "virtual open-loop" in the radio frequency cavity. Figure 7 The complete pulse diagram in a gives a complete picture of the cavity pressure amplitude and phase over time (upper amplitude, lower phase). Figure 7 b (corresponding to) Figure 7 The left gray box highlights the transient details of the load (upper amplitude, lower phase) during beam passage, while the rightmost side presents the beam load vector trajectories under three operating conditions in IQ coordinates. The beam load vector obtained by inversion under "virtual open-loop" conditions (red / ...) V C,VOL ) and open-loop measured vector (green / V cb The two beam load vectors are highly overlapping, while the measured beam load vector under closed loop (blue) is distorted due to the influence of the radio frequency loop.

[0165] like Figure 8 The following is a systematic comparison of this vector relationship under different beam conditions: taking two sets of current intensities of 60 mA and 5 mA, and four beam phases (-90°, -45°, -19°, 0°) as representatives, it can be seen that the beam load vector (red / ) obtained under the "virtual open loop" inversion is... V C,VOL ) and open-loop measured vector (green / V cb The results show a high degree of overlap under all operating conditions. In contrast, the measured beam load vector under closed-loop (blue) conditions is distorted due to the influence of the RF loop. The virtual open-loop method more accurately reflects the beam load effect, proving that the present invention has stable, accurate consistency and repeatability under different current intensities and phases.

[0166] like Figure 9 As shown, under different beam current intensities, the closed-loop method (blue) T w equal τ d (approximately 1.4 microseconds) and the beam phase obtained by the virtual open-loop method of this invention (red) ( T wThe results (selected as 4 microseconds) are compared with the measured BPM results (green). The results show that as the cavity field strength / beam load increases, the phase measurement deviation of the traditional closed-loop method from BPM increases significantly. In contrast, the calculation results based on virtual open-loop in this invention remain consistent with BPM across the entire current intensity range, significantly suppressing systematic deviations under high field strength, and demonstrating higher measurement accuracy and robustness.

[0167] Example 2: Following the above example 1 which provided an online beam synchronization phase measurement method based on virtual open-loop technology, this example provides an online beam synchronization phase measurement device based on virtual open-loop technology. The device provided in this example can implement the online beam synchronization phase measurement method based on virtual open-loop technology of Example 1. This device can be implemented through software, hardware, or a combination of both. For ease of description, this example is described by dividing the functionality into various units. Of course, in implementation, the functions of each unit can be implemented in one or more software and / or hardware components. For example, the device may include integrated or separate functional modules or units to execute the corresponding steps in the methods of Example 1. Since the device in this example is basically similar to the method example, the description process of this example is relatively simple. For relevant details, please refer to the description in Example 1. The example of the online beam synchronization phase measurement device based on virtual open-loop technology provided by this invention is merely illustrative.

[0168] Specifically, the present invention provides an online beam synchronization phase measurement device based on virtual open-loop technology, comprising:

[0169] The signal acquisition unit is configured to obtain the raw cavity pressure of the radio frequency cavity. V c * and the original forward voltage V f * The cavity pressure was obtained by calibration and normalization. V C and forward voltage V F ;

[0170] The cavity differential equation building unit is configured to be based on cavity pressure. V C and forward voltage V F Establish the cavity differential equation;

[0171] The steady-state detuning establishment unit is configured to calculate the steady-state detuning Δ based on the cavity differential equation. ω ;

[0172] The small-signal differential equation establishment unit is configured based on steady-state detuning Δ ωAnd based on the cavity pressure when there is no beam. V C and forward voltage V F The cavity pressure change under the combined effects of the beam current and the radio frequency loop was calculated during closed-loop operation. v c and forward voltage change v f Establish small-signal differential equations;

[0173] The cavity pressure variation solution unit is configured to solve the loop driving term based on small-signal differential equations. u Caused cavity pressure changes v cf ;

[0174] The cavity pressure solving element is configured to be based on cavity pressure variations. v c and cavity pressure changes v cf The cavity pressure change under beam term excitation alone was obtained. v vcb And reconstruct the cavity pressure including beam loading effect under the "virtual open-loop" condition. V C, VOL ;

[0175] The beam phase solving unit is configured to be based on cavity pressure. V C, VOL phase ∠ V C, VOL Calculate beam phase .

[0176] Example 3: This example provides an electronic device corresponding to the online beam synchronization phase measurement method based on virtual open-loop technology provided in Example 1. The electronic device can be an electronic device for the client, such as a mobile phone, laptop, tablet computer, desktop computer, etc., to execute the method of Example 1.

[0177] like Figure 10 As shown, the electronic device includes a processor, a memory, a communication interface, and a bus. The processor, memory, and communication interface are connected via the bus to enable communication between them. The memory stores a computer program that can run on the processor. When the processor runs the computer program, it executes the method of Embodiment 1. The implementation principle and technical effects are similar to those of Embodiment 1, and will not be repeated here. Those skilled in the art will understand that... Figure 10 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computing device on which the present application is applied. The specific computing device may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0178] In a preferred embodiment, the logical instructions in the aforementioned memory can be implemented as software functional units and sold or used as independent products, and can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), and optical discs.

[0179] In a preferred embodiment, the processor can be any type of general-purpose processor such as a central processing unit (CPU) or a digital signal processor (DSP), and is not limited thereto.

[0180] Example 4: This example provides a computer-readable storage medium for storing one or more programs, the one or more programs including computer instructions, which, when executed by a computer, cause the computer to perform the method provided in Example 1 above.

[0181] In a preferred embodiment, the computer-readable storage medium may be a tangible device for holding and storing instructions executable, such as, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination thereof. The computer-readable storage medium stores computer program instructions that cause a computer to perform the method provided in Embodiment 1 above.

[0182] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (devices), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0183] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0184] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0185] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In the description of this specification, the terms "a preferred embodiment," "furthermore," "specifically," "in this embodiment," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments in this specification. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0186] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for online measurement of beam synchronous phase based on virtual open loop technique, characterized in that, include: The original cavity pressure and original forward voltage of the radio frequency cavity are obtained and calibrated and normalized to obtain cavity pressure V C and forward voltage V F ; Based on cavity pressure V C And forward voltage V F Establishing cavity differential equations; Based on cavity micro differential equation calculation of steady-state mistuning Δ ω ; Based on steady-state detuning Δ ω And based on the cavity pressure when there is no beam. V C and forward voltage V F The cavity pressure change under the combined effects of the beam current and the radio frequency loop was calculated during closed-loop operation. v c and forward voltage change v f Establish the small-signal differential equation: ； in, v cf For loop drive items u The resulting change in cavity pressure, Δ ω and ω 0.5 These represent the cavity detuning and half-bandwidth, respectively. t For time, j The imaginary unit; Solving the loop driving term based on small-signal differential equations u Caused cavity pressure changes v cf ,include: The small-signal differential equation is converted into a difference equation, sampling points n of the differential part d v cf / dt are expressed according to the difference of the adjacent two sampling points: ； Substituting the above equation into the small-signal differential equation and simplifying, we get: ； Expanding the above equation using the real and imaginary parts, we get: ； in, v cf,i and v cf,q Corresponding to v cf The real and imaginary parts; u i and u q Corresponding to u The real and imaginary parts, T s The sampling period of the voltage signal; The loop driving term is obtained by solving the above difference equation. u cavity pressure changes caused by individual excitation v cf ; Based on cavity pressure changes v c and cavity pressure changes v cf The cavity pressure change under beam term excitation alone was obtained. v vcb And reconstruct the cavity pressure including beam loading effect under the "virtual open-loop" condition. V C，VOL ; Based on the cavity pressure V C, VOL The phase ∠ V C, VOL Calculate the beam phase .

2. The virtual open-loop technique based beam synchronous phase online measurement method according to claim 1, wherein, Based on the cavity pressure V C And the forward voltage V F The differential equation for the cavity is established as ； in, V C0 and V C1 cavity pressures under no-beam and with-beam conditions, respectively. V C , V F0 and V F1 Forward voltages under no-current and with-current conditions, respectively. V F , V b The beam current equivalent voltage, β is the coupling coefficient.

3. The online beam synchronization phase measurement method based on virtual open-loop technology according to claim 2, characterized in that, Steady state mistuning Δ ω The formula for calculating is: ； where Δ θ is the detuning angle, V F,ss is the forward voltage at steady state before the beam arrives, is V F,ss the phase of 4. The virtual open-loop technique based beam synchronous phase online measurement method according to claim 1, wherein, Based on cavity pressure changes v c and cavity pressure changes v cf The cavity pressure change under beam term excitation alone was obtained. v vcb And reconstruct the cavity pressure including beam loading effect under the "virtual open-loop" condition. V C，VOL The process is as follows: From the change in cavity pressure v c Subtracting cavity pressure changes v cf The cavity pressure change caused by the beam term was obtained. v vcb ; Changes in cavity pressure v vcb The cavity pressure when there is no current is superimposed. V C0 Reconstruct the cavity pressure containing only the beam term V C, VOL : 。 5. The virtual open-loop technique based beam synchronization phase online measurement method of claim 4, wherein, Beam phase The calculation formula is: 。 6. An apparatus for implementing the method of online measurement of the phase of the beam current based on the virtual open-loop technique according to any one of claims 1 to 5, characterized in that include: The signal acquisition unit is configured to obtain the raw cavity pressure of the radio frequency cavity. V c and the original forward voltage V f The cavity pressure was obtained by calibration and normalization. V C and forward voltage V F ; The cavity differential equation establishing unit is configured to establish a cavity differential equation based on a cavity pressure V C and a forward voltage V F establishing a cavity differential equation; a steady-state detuning establishment unit configured to calculate a steady-state detuning Δ based on a cavity differential equation ω ; The small-signal differential equation establishment unit is configured based on steady-state detuning Δ ω And based on the cavity pressure when there is no beam. V C and forward voltage V F The cavity pressure change under the combined effects of the beam current and the radio frequency loop was calculated during closed-loop operation. v c and forward voltage change v f Establish small-signal differential equations; The cavity pressure variation solution unit is configured to solve the loop driving term based on small-signal differential equations. u Caused cavity pressure changes v cf ; The cavity pressure solving element is configured to be based on cavity pressure variations. v c and cavity pressure changes v cf The cavity pressure change under beam term excitation alone was obtained. v vcb And reconstruct the cavity pressure including beam loading effect under the "virtual open-loop" condition. V C, VOL ; The beam phase solving unit is configured to be based on cavity pressure. V C, VOL phase ∠ V C, VOL Calculate beam phase .

7. An electronic device, comprising: include: At least one processor; And a memory communicatively connected to the processor; wherein the memory stores instructions executable by the processor, the instructions being executed by the processor to enable the processor to perform the method according to any one of claims 1-5.

8. A computer-readable storage medium storing one or more programs, the one or more programs comprising instructions that when executed by a computer cause the computer to perform a method of any of claims 1-7. The one or more programs include computer instructions for causing a computer to perform the method according to any one of claims 1-5.

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