Magnetic probe, detection device and detection method for weak flow beam diagnosis of accelerator

Abstract

The invention relates to the technical field of accelerator beam diagnosis, in particular to a magnetic probe, a detection device and a detection method.The magnetic probe comprises a magnetic core ring set, a coil winding and a multi-core connector, and the magnetic core ring set comprises an excitation magnetic core ring, a compensation magnetic core ring and a detection magnetic core ring which are arranged in parallel; the excitation coil and the excitation detection coil are respectively wound on the excitation magnetic core ring, the excitation compensation coil is wound on the compensation magnetic core ring, the alternating current detection coil is wound on the detection magnetic core ring, and the residual ripple detection coil and the current compensation coil are respectively and simultaneously wound on the excitation magnetic core ring, the compensation magnetic core ring and the detection magnetic core ring. A magnetic core ring group is formed by a plurality of groups of magnetic core rings with different functions, a coil winding is formed by a plurality of groups of coils with different functions, corresponding coils are wound on the magnetic core rings based on different functions, a feedback and compensation design of multiple weak magnetic flux differences is formed, and the detection precision can be improved to tens of microamperes. Therefore, high-precision weak direct current detection of the accelerator is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of accelerator beam current diagnosis, and in particular to a magnetic probe, a detection device and a detection method for accelerator weak current beam diagnosis. Background Art

[0002] The beam diagnosis system is one of the most important subsystems of the proton and heavy ion accelerators, which is equivalent to the "eyes" and "five senses" of the accelerator. The diagnosis content includes the monitoring of various parameters such as beam intensity, energy, phase, etc. to ensure the parameter matching and stable operation of the front and rear sections of the accelerator. Among them, the beam intensity measurement and transmission efficiency monitoring are crucial and are one of the important parameters to characterize the performance indicators of the accelerator.

[0003] During the beam diagnosis of proton and heavy ion accelerators, there are sometimes weak currents of microampere or even lower order. These weak currents are generally called "weak currents". The measurement of "weak currents" requires highly sensitive equipment for detection. Among the commonly used current measurement methods for proton and heavy ion machine beam diagnosis, they can be divided into interception probes and non-interception current diagnosis equipment according to whether they block the beam. Among them, interception probes such as Faraday cups can measure weaker currents ("weak currents"), but they will affect the downstream operating conditions due to blocking the beam, and they cannot cope with high-power measurements due to beam power deposition and target head temperature rise. High-energy electrons escape from their surfaces after being bombarded by the beam, which will affect the measurement accuracy to a certain extent. Non-interception current diagnosis equipment generally uses alternating beam macro pulses to generate magnetic flux changes when passing through the magnetic core, and uses this as the working mechanism to form a pulse AC transformer, which can meet the pulsed weak current measurement needs of accelerator beam diagnosis. However, when the macro pulse width is in milliseconds or above, the pulse AC transformer will show a more obvious square wave top drop, which is difficult to work stably and accurately. Summary of the invention

[0004] The present invention provides a magnetic probe, a detection device and a detection method for accelerator weak current beam diagnosis, so as to solve the above-mentioned defects of the current intensity measurement means commonly used in accelerator beam diagnosis in the prior art, form a beam diagnosis detection based on magnetic modulation, and realize high-precision weak current detection of accelerator.

[0005] The present invention provides a magnetic probe for accelerator weak current beam diagnosis, comprising a magnetic core ring group, a coil winding and a multi-core connector, wherein the magnetic core ring group comprises an excitation magnetic core ring, a compensation magnetic core ring and a detection magnetic core ring arranged in parallel; the coil winding comprises an excitation coil, an excitation detection coil, an excitation compensation coil, an AC detection coil, a residual ripple detection coil and a current compensation coil, the excitation coil and the excitation detection coil are respectively wound on the excitation magnetic core ring, the excitation compensation coil is wound on the compensation magnetic core ring, the AC detection coil is wound on the detection magnetic core ring, the residual ripple detection coil and the current compensation coil are respectively and simultaneously wound on the excitation magnetic core ring, the compensation magnetic core ring and the detection magnetic core ring; the multi-core connector comprises a multi-channel signal transmission port, and the excitation coil, the excitation detection coil, the excitation compensation coil, the AC detection coil, the residual ripple detection coil and the current compensation coil respectively form signal transmission ports on the multi-core connector.

[0006] According to a magnetic probe for accelerator weak current beam diagnosis provided by the present invention, the magnetic core ring group includes two groups of excitation magnetic core rings, one group of compensation magnetic core rings and one group of detection magnetic core rings; the coil winding includes two groups of excitation coils, two groups of excitation detection coils, one group of excitation compensation coils, one group of AC detection coils, one group of residual ripple detection coils and one group of current compensation coils.

[0007] The two groups of excitation coils are correspondingly wound on the two groups of excitation core rings, and the two groups of excitation coils have the same number of turns and opposite directions; the two groups of excitation detection coils are correspondingly wound on the two groups of excitation core rings, and the two groups of excitation detection coils have the same number of turns and the same direction; the residual ripple detection coils are sequentially wound on the two groups of excitation core rings, one group of compensation core rings and one group of detection core rings, and the number of turns on each core ring is equal and the direction is the same; the current compensation coils are sequentially wound on the two groups of excitation core rings, one group of compensation core rings and one group of detection core rings, and the number of turns on each core ring is equal and the direction is the same.

[0008] According to a magnetic probe for accelerator weak current beam diagnosis provided by the present invention, the coil winding also includes a calibration coil, and the calibration coil is simultaneously wound around the excitation core ring, the compensation core ring and the detection core ring, and both ends of the calibration coil are externally connected to a standard current source.

[0009] According to a magnetic probe for accelerator weak current beam diagnosis provided by the present invention, the magnetic probe for accelerator weak current beam diagnosis also includes a coaxial vacuum inner tube and a vacuum outer tube, and the two ends of the vacuum inner tube and the vacuum outer tube are respectively connected to sealing flanges to form a vacuum sealed cavity between the vacuum inner tube and the vacuum outer tube; the magnetic core ring group and the coil winding are arranged in the vacuum sealed cavity, and the multi-core connector is passed through the vacuum outer tube.

[0010] According to a magnetic probe for accelerator weak-current beam diagnosis provided by the present invention, magnetic shielding layers are provided on the inner wall of the vacuum outer tube and the end surface of the sealing flange facing the vacuum sealing cavity.

[0011] According to a magnetic probe for accelerator weak current beam diagnosis provided by the present invention, the vacuum inner tube includes a first vacuum tube and a second vacuum tube, and the first vacuum tube and the second vacuum tube are connected by a ceramic ring.

[0012] The present invention also provides a detection device for accelerator weak current beam diagnosis, comprising any one of the magnetic probes for accelerator weak current beam diagnosis described above, and also comprising a controller, wherein the controller is connected to the multi-core connector of the magnetic probe via a connecting cable, and the controller comprises an excitation generator, an excitation detection compensation module, a second harmonic demodulation module, an AC detection module, a residual ripple detection module, a signal processing module, an output module and a power supply module.

[0013] The excitation generator is connected to the excitation coil of the magnetic probe through the connecting cable, and is used to output a square wave excitation voltage with a fixed frequency to the excitation coil; one end of the excitation detection compensation module is connected to the excitation detection coil of the magnetic probe through the connecting cable, and is used to detect the difference in excitation magnetic flux generated in the excitation coil; the other end of the excitation detection compensation module is connected to the excitation compensation coil of the magnetic probe through the connecting cable, and is used to inject an excitation compensation current into the excitation compensation coil; the second harmonic demodulation module is connected to the excitation detection coil of the magnetic probe through the connecting cable, and is used to detect and extract the second harmonic in the excitation detection coil as the DC component in the primary weak current signal to be measured; the AC detection module is connected to the AC detection coil of the magnetic probe through the connecting cable, and is used to extract the AC component in the primary weak current signal to be measured; the residual ripple detection module is connected to the AC detection coil of the magnetic probe through the connecting cable The residual ripple detection coil of the magnetic probe is used to extract the difference between the magnetic flux generated by the primary weak current to be measured and the magnetic flux generated by the current compensation coil to form a residual ripple component; the signal processing module is respectively connected to the second harmonic demodulation module, the AC detection module, the residual ripple detection module and the current compensation coil of the magnetic probe, and is used to phase-lock, filter and gain-amplify the second harmonic output by the second harmonic demodulation module, the AC component output by the AC detection module, and the residual ripple component output by the residual ripple detection module, output a total error signal, and output a compensation current to the current compensation coil based on the total error signal; the output module is connected to the current compensation coil of the magnetic probe through the connecting cable, and is used to detect the current value in the current compensation coil, and convert the current value into an analog voltage value for output; the power supply module is used to provide a low-voltage power supply for the controller.

[0014] According to a detection device for accelerator weak current beam diagnosis provided by the present invention, the controller also includes a power amplification module, which is connected between the signal processing module and the current compensation coil, and is used to power amplify the total error signal output by the signal processing module and output a compensation current to the current compensation coil.

[0015] According to a detection device for accelerator weak flow beam diagnosis provided by the present invention, the controller also includes a gear selection module, which is connected to the power amplifier module and is used to control the gain of the power amplifier module under different weak flow ranges to be measured so that the power amplifier module outputs a signal with an optimal signal-to-noise ratio.

[0016] The present invention also provides a detection method for accelerator weak current beam diagnosis, which is applicable to any of the above detection devices for accelerator weak current beam diagnosis, and the detection method for accelerator weak current beam diagnosis comprises: The excitation generator outputs a square wave excitation voltage with a fixed frequency to the excitation coil, so that the excitation coil generates an alternating excitation current and the excitation core of the excitation core ring alternately reaches a saturation state.

[0017] The excitation detection compensation module detects the difference in excitation magnetic flux generated by the excitation coil, and injects an excitation compensation current into the excitation compensation coil, so that the excitation magnetic core ring as a whole presents a zero magnetic flux state to the outside.

[0018] Based on the second harmonic demodulation module, the second harmonic in the excitation detection coil is detected and extracted as the DC component in the primary weak current signal to be measured, and the signal is output to the signal processing module; based on the AC detection module, the AC component in the primary weak current signal to be measured is extracted, and the signal is output to the signal processing module; based on the residual ripple detection module, the difference between the magnetic flux generated by the primary weak current to be measured and the magnetic flux generated by the current compensation coil is extracted to form a residual ripple component, and the signal is output to the signal processing module.

[0019] The signal processing module performs phase locking, filtering and gain amplification processing based on the second harmonic output by the second harmonic demodulation module, the AC component output by the AC detection module and the residual ripple component output by the residual ripple detection module, and outputs a total error signal.

[0020] The power amplifier module performs power amplification processing based on the total error signal output by the signal processing module, outputs a compensation current to the current compensation coil, and controls the power amplifier module to change the gain through the gear selection module, so that the power amplifier module outputs a signal with the best signal-to-noise ratio.

[0021] The output module detects the current value in the current compensation coil, and converts the detected current value into an analog voltage value for output, and obtains the weak current detection result in the oscilloscope.

[0022] The magnetic probe for accelerator weak current beam diagnosis provided by the present invention comprises a plurality of groups of magnetic core rings with different functions to form a magnetic core ring group, and a plurality of groups of coils with different functions to form a coil winding. Corresponding coils are wound on the magnetic core rings based on different functions to form a feedback and compensation design for multiple weak magnetic flux differences, which can improve the detection accuracy to tens of microamperes, so as to realize high-precision weak DC detection of the accelerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1It is a schematic diagram of the cross-sectional structure of a magnetic probe for accelerator weak-current beam diagnosis provided by the present invention.

[0025] Figure 2 It is a schematic diagram of the connection structure of the detection device for accelerator weak current beam diagnosis provided by the present invention.

[0026] Figure 3 It is a schematic diagram of the working principle of the magnetic probe and controller for accelerator weak current beam diagnosis provided by the present invention.

[0027] Reference numerals: 1. Magnetic core ring assembly; 2. Coil winding; 3. Multi-core connector; 4. Vacuum inner tube; 5. Vacuum outer tube; 6. Sealing flange; 7. Magnetic shielding layer; 8. Ceramic ring; 9. Controller; 10. Connecting cables. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0030] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0031] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0032] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0033] Combine the following Figures 1 to 3 The invention describes a magnetic probe, a detection device and a detection method for accelerator weak-current beam diagnosis.

[0034] One embodiment of the present invention provides a magnetic probe for accelerator weak current beam diagnosis, see Figure 1 As shown, the magnetic probe includes a core ring group 1, a coil winding 2 and a multi-core connector 3. The core ring group 1 includes an excitation core ring, a compensation core ring and a detection core ring arranged in parallel; the coil winding 2 includes an excitation coil, an excitation detection coil, an excitation compensation coil, an AC detection coil, a residual ripple detection coil and a current compensation coil. The excitation coil and the excitation detection coil are respectively wound on the excitation core ring, the excitation compensation coil is wound on the compensation core ring, the AC detection coil is wound on the detection core ring, and the residual ripple detection coil and the current compensation coil are respectively wound on the excitation core ring, the compensation core ring and the detection core ring; the multi-core connector 3 includes a multi-channel signal transmission port, and the excitation coil, the excitation detection coil, the excitation compensation coil, the AC detection coil, the residual ripple detection coil and the current compensation coil respectively form signal transmission ports on the multi-core connector 3.

[0035] It is understandable that in the process of proton and heavy ion accelerator beam current diagnosis, the measurement of "weak current" at the microampere level or even lower requires highly sensitive equipment for detection. The magnetic probe for accelerator weak current beam diagnosis of this embodiment is composed of a magnetic core ring group 1 through multiple groups of magnetic core rings with different functions, and a coil winding 2 through multiple groups of coils with different functions. Corresponding coils are wound on the magnetic core rings based on different functions to form a feedback and compensation design of multiple weak magnetic flux differences, which can improve the detection accuracy to tens of microamperes, so as to realize high-precision weak DC detection of accelerators.

[0036] In some embodiments of the magnetic probe for accelerator weak current beam diagnosis of the present invention, the magnetic core ring group 1 includes two groups of excitation magnetic core rings, one group of compensation magnetic core rings and one group of detection magnetic core rings; the coil winding 2 includes two groups of excitation coils, two groups of excitation detection coils, one group of excitation compensation coils, one group of AC detection coils, one group of residual ripple detection coils and one group of current compensation coils.

[0037] The two groups of excitation coils are correspondingly wound on the two groups of excitation core rings, and the two groups of excitation coils have the same number of turns and opposite directions; the two groups of excitation detection coils are correspondingly wound on the two groups of excitation core rings, and the two groups of excitation detection coils have the same number of turns and the same direction; the residual ripple detection coils are sequentially wound on the two groups of excitation core rings, one group of compensation core rings and one group of detection core rings, and the number of turns on each core ring is equal and the direction is the same; the current compensation coils are sequentially wound on the two groups of excitation core rings, one group of compensation core rings and one group of detection core rings, and the number of turns on each core ring is equal and the direction is the same.

[0038] The magnetic core rings included in the magnetic core ring group 1 of this embodiment have a very high relative magnetic permeability of about 100,000 at low frequency. The magnetic core ring group 1 includes two groups of excitation magnetic core rings. The two groups of excitation magnetic core rings require very high parameter consistency. When the excitation coil feeds currents of the same magnitude and opposite directions, the magnetic fluxes of the two magnetic rings will cancel each other out in an ideal state, and the whole will not generate leakage magnetic flux to the outside. A group of excitation coils and a group of excitation detection coils are respectively wound on each group of excitation magnetic core rings. The magnetic core ring group 1 includes a group of compensation magnetic core rings, on which a group of excitation compensation coils are wound. The magnetic core ring group 1 includes a group of detection magnetic core rings, on which a group of AC detection coils are wound. The two groups of excitation coils have the same number of turns but opposite directions, and are respectively wound on the two groups of excitation magnetic core rings, which can generate an alternating magnetic field, which is helpful for accurately controlling and measuring weak current signals. The two groups of excitation detection coils have the same number of turns and the same direction, and are respectively wound on the two groups of excitation magnetic core rings, and are used to detect the changes in the magnetic field generated by the excitation coils. A group of excitation compensation coils are wound on the compensation core rings to compensate for errors caused by external interference or internal non-uniformity of the system. A group of AC detection coils are wound on the detection core rings to extract the AC component of the primary weak current signal to be measured. A group of residual ripple detection coils are wound on two groups of excitation core rings, one group of compensation core rings and one group of detection core rings in sequence. The number of turns on each core ring is equal and the direction is the same. It is used to detect residual ripple, that is, the difference between the primary weak current to be measured and the current compensation coil. A group of current compensation coils are also wound on two groups of excitation core rings, one group of compensation core rings and one group of detection core rings in sequence. The number of turns on each core ring is equal and the direction is the same. It is used to provide compensation current to offset the errors in the system.

[0039] Through the above-mentioned complex coil winding structure, highly sensitive detection of tiny current changes can be achieved, and the compensation mechanism can be used to reduce system errors and improve measurement accuracy. By injecting compensation current into the excitation compensation coil, the excitation core ring as a whole can present a zero flux state to the outside, further improving the accuracy of the measurement. The magnetic probe design of this embodiment significantly improves the detection capability and stability of weak current signals through complex coil windings and multi-layer feedback compensation mechanisms, so that the magnetic probe can achieve a measurement accuracy of tens of microamperes, which is suitable for the diagnosis needs of accelerator weak beams.

[0040] Furthermore, in some other embodiments of the magnetic probe for accelerator weak current beam diagnosis of the present invention, the coil winding 2 also includes a calibration coil, which is wound around the excitation core ring, the compensation core ring and the detection core ring at the same time, and the two ends of the calibration coil are externally connected to a standard current source. Specifically, the core ring group 1 includes a group of calibration coils, which are also wound around two groups of excitation core rings, one group of compensation core rings and one group of detection core rings in sequence, and the two ends of the calibration coil are connected to the output port of the high-precision standard current source. By injecting a known standard current, the accuracy of the weak current detection current sensor can be calibrated to determine whether its measurement results meet the expected requirements. The number of turns of the calibration coil on each core ring is equal and in the same direction. The number of turns on each core ring is preferably but not limited to 10 turns, ensuring that the calibration current can evenly affect each core ring, thereby improving the accuracy and consistency of the calibration.

[0041] The high-precision standard current source is an external current source that provides high-precision current output with an accuracy of less than 0.01%. The high-precision standard current source is only used when the weak current detection current of the magnetic probe needs to be calibrated for accuracy. The high-precision standard current source is not used when the magnetic probe is working normally. During the calibration accuracy process, one or more standard current values ​​are selected for testing according to the calibration requirements. The output port of the high-precision standard current source is connected to both ends of the calibration coil. A high-precision standard current is input into the calibration coil to generate a corresponding magnetic field. The current detection output value of the magnetic probe is recorded, and the actual output value is compared with the theoretical value to evaluate whether its accuracy meets the requirements. It should be understood that when calibrating the accuracy, the weak current must be zero to ensure that there is no other current interference during the calibration process, otherwise it will affect the accuracy of the calibration result.

[0042] In some embodiments of the magnetic probe for accelerator weak current beam diagnosis of the present invention, see Figure 1 As shown, the magnetic probe for accelerator weak current beam diagnosis also includes a coaxial vacuum inner tube 4 and a vacuum outer tube 5, and the two ends of the vacuum inner tube 4 and the vacuum outer tube 5 are respectively connected to sealing flanges 6 to form a vacuum sealed cavity between the vacuum inner tube 4 and the vacuum outer tube 5; the magnetic core ring group 1 and the coil winding 2 are arranged in the vacuum sealed cavity, and the multi-core connector 3 is passed through the vacuum outer tube 5.

[0043] It can be understood that in this embodiment, the vacuum outer tube 5 is coaxially arranged around the vacuum inner tube 4, and a sealed cavity is formed between the two. The sealing flange 6 is a component connected to both ends of the vacuum inner tube 4 and the vacuum outer tube 5 to ensure that the space between the two tubes is completely sealed, thereby forming a vacuum environment. The key components such as the magnetic core ring group 1 and the coil winding 2 are placed in the vacuum sealed cavity formed by the vacuum inner tube 4, the vacuum outer tube 5 and the sealing flange 6, which helps to protect these sensitive components from the influence of the external environment, such as humidity, dust and other factors that may interfere with the signal. The multi-core connector 3 is inserted into the vacuum outer tube, allowing the signal to be transmitted from the internal magnetic core ring group 1 and the coil winding 2 to the external device for processing, which not only ensures the stable transmission of the signal, but also maintains the vacuum sealing of the entire system.

[0044] The sealing flange 6 can be, but is not limited to, a 304 or 316LN stainless steel standard CF flange. During beam diagnosis of the accelerator, the sealing flange 6 is used to connect with the upstream and downstream pipelines and perform vacuum sealing. The particle beam in the proton or heavy ion accelerator flows through the vacuum inner tube 4 via the sealing flange 6 from the upstream and downstream pipelines. During this process, the magnetic core ring group 1 and the coil winding 2 between the vacuum inner tube 4 and the vacuum outer tube 5 perform beam diagnosis detection.

[0045] In some specific examples, a magnetic shielding layer 7 is provided on the inner wall of the vacuum outer tube 5 and the end surface of the sealing flange 6 facing the vacuum sealing cavity. The main function of the magnetic shielding layer 7 is to shield the influence of the external magnetic field on the internal magnetic core ring group 1 and the coil winding 2, thereby improving the measurement accuracy. By isolating the external magnetic field, the magnetic shielding layer 7 can protect the magnetic core ring group 1 and the coil winding 2 from unnecessary electromagnetic interference to ensure their normal operation. The magnetic shielding layer 7 can be made of high magnetic permeability materials (such as Permalloy or soft ferrite), which have excellent magnetic shielding properties, and prevent the magnetic core ring from being affected by the leakage magnetic field of the upstream and downstream magnets of the accelerator during operation. Figure 1 The direction of the arrow in the figure indicates the bypass direction of the image current formed by the magnetic shielding layer 7, so as to ensure that when the magnetic core ring group 1 is working, the electromagnetic field signal generated by the primary weak current will not be offset by the image current signal of the vacuum pipe in the ring. The magnetic shielding layer 7 guides the external magnetic field to bypass the magnetic core ring group 1 through its high magnetic permeability material, reducing the influence of the external magnetic field on the internal measurement. The magnetic shielding layer 7 effectively shields the external magnetic field, ensuring that the magnetic core ring group can accurately measure the electromagnetic field signal generated by the primary weak current without being masked by external interference signals.

[0046] Further, the vacuum inner tube 4 includes a first vacuum tube and a second vacuum tube, and the first vacuum tube and the second vacuum tube are connected by a ceramic ring 8. The first vacuum tube is a part of the vacuum inner tube 4, usually located at one end close to the upstream pipeline, and the second vacuum tube is also another part of the vacuum inner tube 4, usually located at one end close to the downstream pipeline. The ceramic ring 8 is an intermediate piece for connecting the first vacuum tube and the second vacuum tube. The ceramic ring 8 has excellent electrical insulation performance, which can effectively prevent the current from being directly conducted between the two vacuum tubes, avoiding short circuits or other electrical problems. In a high vacuum environment, when the particle beam passes through the vacuum pipeline, an induced current (image current) will be generated on the pipeline wall, and these currents will interfere with the measurement of the weak beam signal by the magnetic core ring group 1. The ceramic ring 8 isolates the induced image current through its electrical insulation characteristics, so that it cannot be directly conducted along the vacuum pipeline wall, but bypasses the periphery of the magnetic core ring and passes downward, so that the image current and the electromagnetic field signal generated by the primary weak current can be prevented from canceling each other, thereby improving the measurement accuracy.

[0047] It should be understood that in other embodiments of the magnetic probe for accelerator weak-current beam diagnosis of the present invention, it may only include three components: a magnetic core ring group 1, a coil winding 2, and a multi-core connector 3. The exposed magnetic probe is processed by glue filling or the like and can be applied to the outer wall of a vacuum pipe or a test object. Its application scenario is more flexible, but it is also more susceptible to environmental leakage magnetic field and noise.

[0048] Another aspect of the present invention provides a detection device for accelerator weak current beam diagnosis, see Figure 2 As shown, in some embodiments, the detection device includes any one of the above-mentioned magnetic probes for accelerator weak current beam diagnosis, and also includes a controller 9, the controller 9 is connected to the multi-core connector 3 of the magnetic probe through a connecting cable 10, and the controller 9 includes an excitation generator, an excitation detection compensation module, a second harmonic demodulation module, an AC detection module, a residual ripple detection module, a signal processing module, an output module and a power supply module.

[0049] The excitation generator is connected to the excitation coil of the magnetic probe through a connecting cable 10, and is used to output a square wave excitation voltage with a fixed frequency to the excitation coil; one end of the excitation detection compensation module is connected to the excitation detection coil of the magnetic probe through a connecting cable 10, and is used to detect the difference in excitation magnetic flux generated in the excitation coil; the other end of the excitation detection compensation module is connected to the excitation compensation coil of the magnetic probe through a connecting cable 10, and is used to inject an excitation compensation current into the excitation compensation coil; the second harmonic demodulation module is connected to the excitation detection coil of the magnetic probe through a connecting cable 10, and is used to detect and extract the second harmonic in the excitation detection coil as the DC component in the primary weak current signal to be measured; the AC detection module is connected to the AC detection coil of the magnetic probe through the connecting cable 10, and is used to extract the AC component in the primary weak current signal to be measured; the residual ripple detection module is connected to the The residual ripple detection coil of the magnetic probe is used to extract the difference between the magnetic flux generated by the primary weak current to be measured and the magnetic flux generated by the current compensation coil to form a residual ripple component; the signal processing module is respectively connected to the second harmonic demodulation module, the AC detection module, the residual ripple detection module and the current compensation coil of the magnetic probe, and is used to phase-lock, filter and gain-amplify the second harmonic output by the second harmonic demodulation module, the AC component output by the AC detection module, and the residual ripple component output by the residual ripple detection module, output a total error signal, and output a compensation current to the current compensation coil based on the total error signal; the output module is connected to the current compensation coil of the magnetic probe through a connecting cable 10, and is used to detect the current value in the current compensation coil, and convert the current value into an analog voltage value for output; the power supply module is used to provide a low-voltage power supply for the controller 9.

[0050] It can be understood that the controller 9 is connected to the multi-core connector 3 of the magnetic probe through the connecting cable 10, and is responsible for the generation, processing and output of the signal. The excitation generator outputs a square wave excitation voltage with a fixed frequency to the excitation coil of the magnetic probe to generate an alternating magnetic field, which provides a basic signal source for subsequent magnetic field measurement. The input end of the excitation detection compensation module is connected to the excitation detection coil of the magnetic probe, which is used to detect the difference in the excitation magnetic flux generated in the excitation coil, and the output end is connected to the excitation compensation coil of the magnetic probe, which is used to inject an excitation compensation current into the excitation compensation coil. The excitation detection compensation module ensures the stability and accuracy of the system by detecting and compensating the difference in the magnetic flux in the excitation coil. The second harmonic demodulation module is connected to the excitation detection coil of the magnetic probe, detects and extracts the second harmonic in the excitation detection coil as the DC component in the primary weak current signal to be measured, and separates the second harmonic component in the high-frequency signal to extract the DC component of the primary weak current to be measured, thereby improving the measurement accuracy. The AC detection module is connected to the AC detection coil of the magnetic probe, extracts the AC component in the primary weak current signal to be measured, and separates the AC part in the signal to be measured, which is convenient for further analysis and processing. The residual ripple detection module is connected to the residual ripple detection coil of the magnetic probe, extracts the difference between the magnetic flux generated by the primary weak current to be measured and the magnetic flux generated by the current compensation coil, forms the residual ripple component, detects the residual ripple, evaluates the system error, and performs corresponding compensation. The signal processing module performs phase locking, filtering, and gain amplification processing on the second harmonic output by the second harmonic demodulation module, the AC component output by the AC detection module, and the residual ripple component output by the residual ripple detection module, outputs the total error signal, and outputs the compensation current to the current compensation coil based on the total error signal, comprehensively processes various signals, eliminates noise and interference, and generates high-precision measurement results. The output module is connected to the current compensation coil of the magnetic probe, detects the current value in the current compensation coil, and converts the current value into an analog voltage value for output, and converts the final measurement result into a voltage signal that is easy to read and use.

[0051] The working process of the detection device for accelerator weak current beam diagnosis in this embodiment mainly includes the processes of excitation signal generation, signal detection and compensation, signal processing and compensation, and result output.

[0052] Excitation signal generation: The excitation generator outputs a fixed-frequency square wave excitation voltage to the excitation coil to generate an alternating magnetic field.

[0053] Signal detection and compensation: The excitation detection and compensation module detects the magnetic flux difference in the excitation coil and injects compensation current into the excitation compensation coil. The second harmonic demodulation module extracts the second harmonic from the excitation detection coil as the DC component of the primary weak current to be measured. The AC detection module extracts the AC component of the primary weak current to be measured. The residual ripple detection module detects the magnetic flux difference between the primary weak current to be measured and the current compensation coil to form the residual ripple component.

[0054] Signal processing and compensation: The signal processing module performs phase locking, filtering and gain amplification processing on the above-mentioned various signals, generates a total error signal, and outputs a compensation current to the current compensation coil.

[0055] Result output: The output module converts the current value in the current compensation coil into an analog voltage value for output.

[0056] The detection device for accelerator weak beam diagnosis in this embodiment achieves high-precision measurement of accelerator weak beam through precise design and coordinated operation of multiple modules, and is suitable for weak beam diagnosis needs in complex environments such as proton or heavy ion accelerators. Through multiple signal processing technologies, the high accuracy and stability of the measurement results are ensured, and through signal compensation and shielding design, the influence of external electromagnetic interference on the measurement results is reduced.

[0057] In some embodiments of the detection device for accelerator weak beam diagnosis of the present invention, the controller 9 also includes a power amplifier module, which is connected between the signal processing module and the current compensation coil, and is used to perform power amplification processing on the total error signal output by the signal processing module, and output a compensation current to the current compensation coil. The power amplifier module is located between the signal processing module and the current compensation coil, and its input end receives the total error signal output from the signal processing module. After power amplification processing, the compensation current is output from the output end to the current compensation coil. The power amplifier module performs power amplification processing on the total error signal generated by the signal processing module to ensure that the output compensation current is strong enough to offset the error in the system and maintain high-precision measurement. By amplifying the signal, a sufficient signal-to-noise ratio can be obtained even in the case of a weak beam, thereby improving the sensitivity and reliability of the system.

[0058] Further, the controller 9 also includes a gear selection module, which is connected to the power amplifier module and is used to control the gain of the power amplifier module under different weak flow ranges to be measured, so that the power amplifier module outputs a signal with the best signal-to-noise ratio. The gear selection module is connected to the power amplifier module, and is used when the superconducting linear accelerator is in weak flow debugging and normal operation, and the synchronous ring accelerator is in multi-turn accumulation and variable frequency acceleration. The measured flow intensity will change greatly to several orders of magnitude, so it is necessary to control the power amplifier module to perform corresponding gain changes to ensure the output of the signal with the best signal-to-noise ratio. The power amplifier module is controlled to dynamically adjust the gain of the power amplifier module according to different weak flow ranges to be measured, and automatically select the appropriate gain setting under different weak flow ranges to be measured to ensure the best signal-to-noise ratio. By intelligently selecting the gain gear, the measurement error caused by the signal being too strong or too weak is avoided, and the overall performance and stability of the system are improved.

[0059] This embodiment ensures that the intensity of the compensation current is large enough through the power amplification module, which can effectively offset the system error and improve the measurement accuracy; the gear selection module adjusts the gain according to different ranges to avoid measurement errors caused by too strong or too weak signals and ensure the best signal-to-noise ratio. Multi-level signal processing and gain adjustment are formed to reduce the impact of external electromagnetic interference on the measurement results and improve the stability and reliability of the system.

[0060] Another aspect of the present invention further provides a detection method for accelerator weak current beam diagnosis, which is applicable to the detection device for accelerator weak current beam diagnosis of any one of the above embodiments. The detection method for accelerator weak current beam diagnosis includes the following steps S1 to S6.

[0061] S1. The excitation generator outputs a square wave excitation voltage with a fixed frequency to the excitation coil, causing the excitation coil to generate an alternating excitation current and causing the excitation core of the excitation core ring to alternately reach a saturation state.

[0062] S2. Detect the difference of the excitation magnetic flux generated by the excitation coil based on the excitation detection compensation module, and inject an excitation compensation current into the excitation compensation coil so that the excitation magnetic core ring as a whole presents a zero magnetic flux state to the outside.

[0063] S3. Based on the second harmonic demodulation module, the second harmonic in the excitation detection coil is detected and extracted as the DC component in the primary weak current signal to be measured, and the signal is output to the signal processing module; based on the AC detection module, the AC component in the primary weak current signal to be measured is extracted, and the signal is output to the signal processing module; based on the residual ripple detection module, the difference between the magnetic flux generated by the primary weak current to be measured and the magnetic flux generated by the current compensation coil is extracted to form a residual ripple component, and the signal is output to the signal processing module.

[0064] S4. The signal processing module performs phase locking, filtering and gain amplification processing based on the second harmonic output by the second harmonic demodulation module, the AC component output by the AC detection module, and the residual ripple component output by the residual ripple detection module, and outputs a total error signal.

[0065] S5, the power amplifier module performs power amplification processing based on the total error signal output by the signal processing module, and outputs a compensation current to the current compensation coil. In this process, the power amplifier module is controlled by the gear selection module to change the gain so that the power amplifier module outputs a signal with the best signal-to-noise ratio.

[0066] S6. The output module detects the current value in the current compensation coil, and converts the detected current value into an analog voltage value for output, and obtains the weak current detection result in the oscilloscope.

[0067] See also Figure 3The working principle diagram of the magnetic probe and controller shown in the figure, the magnetic core ring group 1 includes two groups of excitation magnetic core rings, one group of compensation magnetic core rings and one group of detection magnetic core rings; the coil winding 2 includes two groups of excitation coils, two groups of excitation detection coils, one group of excitation compensation coils, one group of AC detection coils, one group of residual ripple detection coils, one group of current compensation coils and one group of calibration coils. It can be understood that the detection method for accelerator weak current beam diagnosis in this embodiment includes the process of excitation signal generation-excitation compensation-second harmonic demodulation-AC component extraction-residual ripple component extraction-signal processing-power amplification-gain adjustment-result output.

[0068] Excitation signal generation: The excitation generator of the controller 9 is connected to the excitation coil of the magnetic probe through the connecting cable 10 and the multi-core connector 3, and outputs a square wave excitation voltage with a fixed frequency to the excitation coil, so that the excitation coil generates an alternating excitation current, and the excitation core of the excitation core ring alternately reaches a saturation state, providing a basic signal source for subsequent magnetic field measurements, ensuring that the system can accurately measure the primary weak current signal to be measured. The waveform of the excitation voltage is preferably a square wave, the frequency is preferably 31kHz, and the voltage amplitude is preferably such that the excitation core can quickly reach a saturation state alternately. The square wave voltage excitation source can make the key sensitivity parameters of the magnetic probe of the present invention not be affected by the excitation field itself, and will not change with the signal field of the primary weak current to be measured, and has high independence and stability.

[0069] Excitation compensation: One end of the excitation detection compensation module of the controller 9 is connected to the excitation detection coil for detecting the difference in the excitation magnetic flux generated in the excitation coil, and the other end is connected to the excitation compensation coil for injecting the excitation compensation current. The excitation detection coils have equal turns and the same direction, and are respectively wound on the excitation magnetic core rings. They are used to detect the difference in the size of the magnetic flux excited by the two excitation coils on the two excitation magnetic core rings when they are actually used. The excitation compensation coil is separately wound on the compensation magnetic core ring, and the excitation detection coil is used as a signal input. The output signal is used to compensate for the difference in the magnetic flux of the excitation coil.

[0070] Based on the excitation detection compensation module, the difference in the excitation magnetic flux generated by the excitation coil is detected, and an excitation compensation current is injected into the excitation compensation coil. The magnetic flux difference in the excitation coil is eliminated by the compensation current, so that the excitation core ring as a whole presents a zero magnetic flux state to the outside, reducing system errors and ensuring the stability and accuracy of the system.

[0071] Second harmonic demodulation: The second harmonic demodulation module of the controller 9 is connected to the excitation detection coil, and is used to pick up the DC component in the weak current signal to be measured, and output the signal to the signal processing module. The present invention is preferably, but not limited to, using the second harmonic component for signal demodulation. All even harmonic signals can also be used for demodulation. The essence of even harmonic magnetic modulation is to utilize the symmetrical nonlinear characteristics of the hysteresis loop of soft magnetic materials. When the excitation field and the DC or low-frequency signal field exist at the same time, the signal field will accelerate the early saturation of the magnetic core in the first half of the cycle, and will counteract the excitation field in the second half of the cycle to make it saturated later. The difference in the rate of change of magnetic flux in these two half cycles produces an even harmonic signal, and the presence of the signal field has almost no effect on the odd harmonics.

[0072] Based on the second harmonic demodulation module, the second harmonic in the excitation detection coil is detected and extracted, and the second harmonic component in the high-frequency signal is separated to extract the DC component of the primary weak current to be measured, thereby improving the measurement accuracy and ensuring the accurate extraction of the DC component.

[0073] AC component extraction: The AC detection module of the controller 9 is connected to the AC detection coil to extract the AC component in the weak current signal to be tested. The AC detection coil is wound on the detection core ring separately to pick up the AC component in the weak current signal to be tested. The AC component in the weak current signal to be tested is extracted based on the AC detection module, and the signal is output to the signal processing module. The AC detection module separates the AC part of the signal to be tested, which is convenient for further analysis and processing, ensuring the accurate extraction of the AC component and providing basic data for further signal processing.

[0074] Residual ripple component extraction: The residual ripple detection module of the controller 9 is connected to the residual ripple detection coil, and is used to extract the difference between the magnetic flux generated by the weak current to be measured and the magnetic flux generated by the current compensation coil. The residual ripple detection coil is wound on the excitation core ring, the compensation core ring and the detection core ring, and is used to pick up the size of the residual ripple and output a signal to the signal processing module. Based on the residual ripple detection module, the difference between the magnetic flux generated by the weak current to be measured and the magnetic flux generated by the current compensation coil is extracted to form a residual ripple component, and the signal is output to the signal processing module. The residual ripple detection module detects the residual ripple, evaluates the system error, and performs corresponding compensation to reduce the system error and ensure the accuracy of the final measurement result.

[0075] Signal processing: The signal processing module of the controller 9 is connected to the second harmonic demodulation module, the AC detection module, and the residual ripple detection module. The signal processing module performs phase locking, filtering, and gain amplification based on the second harmonic (DC error input) output by the second harmonic demodulation module, the AC component (AC error input) output by the AC detection module, and the residual ripple component (residual error input) output by the residual ripple detection module, and outputs a total error signal. The signal processing module comprehensively processes various signals, eliminates noise and interference, generates high-precision measurement results, ensures the purity and accuracy of the signal, and provides reliable data for subsequent compensation.

[0076] Power amplification: The power amplification module of the controller 9 is connected to the signal processing module and the current compensation coil, and is used to power amplify the input total error signal and output the compensation current to the current compensation coil. The current compensation coil is wound on the excitation core ring, the compensation core ring and the detection core ring, and is used to transmit the processed and amplified compensation current to ensure the zero flux state in the entire measurement space. The power amplification module performs power amplification based on the total error signal output by the signal processing module, and outputs the compensation current to the current compensation coil, enhancing the strength of the compensation current, ensuring that it is strong enough to offset the system error, improve the sensitivity and reliability of the system, and ensure high-precision measurement.

[0077] Gain adjustment: The gear selection module of the controller 9 is connected to the power amplifier module, and is used to control the gain of the power amplifier module under different weak flow ranges to be measured, so that the measurement system can change the range and maintain the best signal-to-noise ratio. The gear control module is used when the superconducting linear accelerator is in weak flow debugging and normal operation, and the synchronous ring accelerator is in multi-turn accumulation and variable frequency acceleration. The measured flow intensity will change greatly to several orders of magnitude, so it is necessary to control the power amplifier module to make corresponding gain changes to ensure the output of the signal with the best signal-to-noise ratio. The gear selection module dynamically adjusts the gain of the power amplifier module according to different weak flow ranges to be measured, optimizes the signal quality, ensures the best signal-to-noise ratio, and avoids measurement errors caused by too strong or too weak signals.

[0078] Result output: The output module of the controller 9 is connected to the current compensation coil to detect the current value in the current compensation coil and convert the current value into an analog voltage value for output, and obtain the weak current detection result in the oscilloscope. The output module converts the final measurement result into a voltage signal that is easy to read and use, making it convenient for users to view and analyze the measurement results, ensuring the intuitiveness and operability of the data.

[0079] It should be understood that the calibration coil is used to calibrate the weak current detection accuracy of the detection device. Before starting the above-mentioned detection method, the accuracy test is first performed through the calibration coil. Before calibration, it is necessary to ensure that the weak current is zero. Then, the output port of the high-precision standard current source is connected to the two ends of the calibration coil. The standard current is injected into the calibration coil through the high-precision standard current source to make the calibration coil generate a corresponding magnetic field. A process similar to the above-mentioned detection method is adopted (for details, please refer to the accuracy calibration process of the current sensor in the prior art), the output value of the controller output module is recorded, and the actual output value is compared with the theoretical value. It is possible to evaluate whether the weak current detection accuracy of the detection device meets the requirements.

[0080] The following describes the detection method for accelerator weak current beam diagnosis of the present invention in combination with the test results of a specific example. It should be noted that the magnetic probe used in this example only includes three components: a magnetic core ring group 1, a coil winding 2, and a multi-core connector 3. It is processed into an exposed magnetic probe through glue filling, etc., and does not include components such as a vacuum inner tube 4, a vacuum outer tube 5, a magnetic shielding layer 7, and a sealing flange 6. The system noise and background measured in this example will be relatively larger.

[0081] Specifically, using the standard current source meter Keithley6221, when the square wave current of 120µA, 100Hz, and 50% duty cycle is input through the calibration coil, the oscilloscope measures that the voltage signal output by the controller 9 at 20mA / 10V is about 60mV, which is converted to 120µA after the gear is converted. At this time, the noise width is about 60µA, and there is still about 2 times the signal-to-noise ratio. At this time, because the bare magnetic ring test has no magnetic shielding structure, it may be affected by 50Hz power supply noise and other interference. The complete shielded magnetic probe can easily measure weak DC or low-frequency signals of the order of tens of microamperes, which can meet the detection needs of accelerator weak current beam diagnosis.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A magnetic probe for accelerator weak beam diagnosis, characterized in that: include: A magnetic core ring group (1), the magnetic core ring group (1) comprising an excitation magnetic core ring, a compensation magnetic core ring and a detection magnetic core ring arranged in parallel; A coil winding (2), the coil winding (2) comprising an excitation coil, an excitation detection coil, an excitation compensation coil, an AC detection coil, a residual ripple detection coil and a current compensation coil, the excitation coil and the excitation detection coil being respectively wound on the excitation magnetic core ring, the excitation compensation coil being wound on the compensation magnetic core ring, the AC detection coil being wound on the detection magnetic core ring, the residual ripple detection coil and the current compensation coil being respectively and simultaneously wound on the excitation magnetic core ring, the compensation magnetic core ring and the detection magnetic core ring; The multi-core connector (3) comprises a multi-channel signal transmission port, wherein the excitation coil, the excitation detection coil, the excitation compensation coil, the AC detection coil, the residual ripple detection coil and the current compensation coil respectively form signal transmission ports on the multi-core connector (3).

2. The magnetic probe for accelerator weak current beam diagnosis according to claim 1, characterized in that: The magnetic core ring group (1) includes two groups of the excitation magnetic core rings, one group of the compensation magnetic core rings and one group of the detection magnetic core rings; the coil winding (2) includes two groups of the excitation coils, two groups of the excitation detection coils, one group of the excitation compensation coils, one group of the AC detection coils, one group of the residual ripple detection coils and one group of the current compensation coils; The two groups of excitation coils are correspondingly wound on the two groups of excitation core rings, and the two groups of excitation coils have the same number of turns and opposite directions; the two groups of excitation detection coils are correspondingly wound on the two groups of excitation core rings, and the two groups of excitation detection coils have the same number of turns and the same direction; the residual ripple detection coils are sequentially wound on the two groups of excitation core rings, one group of compensation core rings and one group of detection core rings, and the number of turns on each core ring is equal and the direction is the same; the current compensation coils are sequentially wound on the two groups of excitation core rings, one group of compensation core rings and one group of detection core rings, and the number of turns on each core ring is equal and the direction is the same.

3. The magnetic probe for accelerator weak current beam diagnosis according to claim 1, characterized in that: The coil winding (2) also includes a calibration coil, which is wound around the excitation magnetic core ring, the compensation magnetic core ring and the detection magnetic core ring at the same time, and both ends of the calibration coil are externally connected to a standard current source.

4. The magnetic probe for accelerator weak current beam diagnosis according to any one of claims 1 to 3, characterized in that: The magnetic probe for accelerator weak current beam diagnosis further comprises a coaxial vacuum inner tube (4) and a vacuum outer tube (5), wherein both ends of the vacuum inner tube (4) and the vacuum outer tube (5) are respectively connected to sealing flanges (6) to form a vacuum sealed cavity between the vacuum inner tube (4) and the vacuum outer tube (5); the magnetic core ring group (1) and the coil winding (2) are arranged in the vacuum sealed cavity, and the multi-core connector (3) is passed through the vacuum outer tube (5).

5. The magnetic probe for accelerator weak current beam diagnosis according to claim 4, characterized in that: A magnetic shielding layer (7) is provided on the inner wall of the vacuum outer tube (5) and on the end surface of the sealing flange (6) facing the vacuum sealing cavity.

6. The magnetic probe for accelerator weak current beam diagnosis according to claim 4, characterized in that: The vacuum inner tube (4) comprises a first vacuum tube and a second vacuum tube, and the first vacuum tube and the second vacuum tube are connected via a ceramic ring (8).

7. A detection device for accelerator weak beam diagnosis, characterized in that: A magnetic probe for accelerator weak current beam diagnosis according to any one of claims 1 to 6, further comprising a controller (9), wherein the controller (9) is connected to the multi-core connector (3) of the magnetic probe via a connecting cable (10), and the controller (9) comprises: an excitation generator, connected to the excitation coil of the magnetic probe via the connecting cable (10), and used to output a square wave excitation voltage with a fixed frequency to the excitation coil; An excitation detection compensation module, one end of which is connected to the excitation detection coil of the magnetic probe via the connection cable (10) and is used to detect the difference in excitation magnetic flux generated in the excitation coil; and the other end of which is connected to the excitation compensation coil of the magnetic probe via the connection cable (10) and is used to inject an excitation compensation current into the excitation compensation coil; A second harmonic demodulation module, connected to the excitation detection coil of the magnetic probe via the connection cable (10), for detecting and extracting the second harmonic in the excitation detection coil as a DC component in the primary weak current signal to be measured; An AC detection module, connected to the AC detection coil of the magnetic probe via the connection cable (10), and used to extract the AC component in the primary weak current signal to be detected; A residual ripple detection module, connected to the residual ripple detection coil of the magnetic probe via the connecting cable (10), for extracting the difference between the magnetic flux generated by the primary weak current to be measured and the magnetic flux generated by the current compensation coil, to form a residual ripple component; a signal processing module, connected to the second harmonic demodulation module, the AC detection module, the residual ripple detection module and the current compensation coil of the magnetic probe, respectively, for performing phase locking, filtering and gain amplification processing on the second harmonic output by the second harmonic demodulation module, the AC component output by the AC detection module and the residual ripple component output by the residual ripple detection module, outputting a total error signal, and outputting a compensation current to the current compensation coil based on the total error signal; An output module, connected to the current compensation coil of the magnetic probe via the connection cable (10), used to detect the current value in the current compensation coil and convert the current value into an analog voltage value for output; A power supply module is used to provide a low-voltage power supply to the controller (9).

8. The detection device for accelerator weak current beam diagnosis according to claim 7, characterized in that: The controller (9) further comprises a power amplification module, which is connected between the signal processing module and the current compensation coil and is used for performing power amplification processing on the total error signal output by the signal processing module and outputting a compensation current to the current compensation coil.

9. The detection device for accelerator weak current beam diagnosis according to claim 8, characterized in that: The controller (9) further comprises a gear selection module, the gear selection module being connected to the power amplification module and being used to control the gain of the power amplification module under different weak flow ranges to be measured, so that the power amplification module outputs a signal with an optimal signal-to-noise ratio.

10. A detection method for accelerator weak beam diagnosis, characterized in that: The detection device for accelerator weak current beam diagnosis according to any one of claims 7 to 9, wherein the detection method for accelerator weak current beam diagnosis comprises: The excitation generator outputs a square wave excitation voltage with a fixed frequency to the excitation coil, so that the excitation coil generates an alternating excitation current and the excitation core of the excitation core ring alternately reaches a saturation state; The excitation detection compensation module detects the difference of the excitation magnetic flux generated by the excitation coil, and injects an excitation compensation current into the excitation compensation coil, so that the excitation magnetic core ring as a whole presents a zero magnetic flux state to the outside; Based on the second harmonic demodulation module, the second harmonic in the excitation detection coil is detected and extracted as the DC component in the primary weak current signal to be measured, and the signal is output to the signal processing module; based on the AC detection module, the AC component in the primary weak current signal to be measured is extracted, and the signal is output to the signal processing module; based on the residual ripple detection module, the difference between the magnetic flux generated by the primary weak current to be measured and the magnetic flux generated by the current compensation coil is extracted to form a residual ripple component, and the signal is output to the signal processing module; The signal processing module performs phase locking, filtering and gain amplification processing based on the second harmonic output by the second harmonic demodulation module, the AC component output by the AC detection module, and the residual ripple component output by the residual ripple detection module, and outputs a total error signal; The power amplifier module performs power amplification processing based on the total error signal output by the signal processing module, outputs a compensation current to the current compensation coil, and controls the power amplifier module to change the gain through the gear selection module, so that the power amplifier module outputs a signal with an optimal signal-to-noise ratio; The output module detects the current value in the current compensation coil, and converts the detected current value into an analog voltage value for output, and obtains the weak current detection result in the oscilloscope.

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