Magnetic Probe, Detection Device and Detection Method for Weak Beam Diagnosis of Accelerator

Abstract

The present invention relates to the technical field of accelerator beam diagnosis, and particularly relates to a magnetic probe, a detection device and a detection method for weak beam diagnosis of an accelerator. The magnetic probe includes a magnetic core ring group, a coil winding and a multi-core connector. The magnetic core ring group includes an excitation magnetic core ring, a compensation magnetic core ring and a detection magnetic core ring arranged in parallel. An excitation coil and an excitation detection coil are respectively wound around the excitation magnetic core ring, an excitation compensation coil is wound around the compensation magnetic core ring, an AC detection coil is wound around the detection magnetic core ring, and a residual ripple detection coil and a current compensation coil are respectively and simultaneously wound around the excitation magnetic core ring, the compensation magnetic core ring and the detection magnetic core ring. A magnetic core ring group is formed by multiple magnetic core rings with different functions, and a coil winding is formed by multiple coils with different functions. Based on different functions, the corresponding coils are wound around the magnetic core rings to form a feedback and compensation design with multiple weak magnetic flux differences, which can improve the detection accuracy to the order of dozens of microamperes to achieve high-precision weak DC detection of the accelerator.

Description

Technical Field

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

[0002] The beam diagnosis (beam current diagnosis) system is one of the very important subsystems on proton and heavy ion accelerators, equivalent to the "eyes" and "senses" of the accelerator. The diagnosis content includes monitoring various parameters such as beam current intensity, energy, and phase to ensure the parameter matching and stable operation of each section before and after the accelerator. Among them, the measurement of beam current intensity and the monitoring of transmission efficiency are crucial and are important parameters characterizing the performance indicators of the accelerator.

[0003] During the beam diagnosis of proton and heavy ion accelerators, there are sometimes weak current intensities in the microampere level or even lower levels, which are generally referred to as "weak currents". The measurement of "weak currents" requires high-sensitivity equipment for detection. Among the commonly used beam current measurement methods for proton and heavy ion machines, according to whether they block the beam, they can be divided into intercepting probes and non-intercepting beam current diagnosis devices. Among them, intercepting probes such as Faraday cups can measure relatively weak current intensities ("weak currents"), but they will affect the downstream operating conditions due to blocking the beam, and due to beam power deposition and target head temperature rise, they cannot handle high-power measurements. There will be high-energy electrons escaping from its surface after being bombarded by the beam, which will affect the measurement accuracy to a certain extent. Non-intercepting beam current diagnosis devices generally use the magnetic flux change generated when an alternating beam macro-pulse passes through a magnetic core as the working mechanism to form a pulse AC transformer, which can meet the pulsed weak current measurement requirements of accelerator beam diagnosis. However, when the macro-pulse width is in milliseconds or above, the pulse AC transformer will show a relatively obvious square wave top drop and it 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 weak beam diagnosis of an accelerator to solve the above defects existing in the commonly used beam current measurement means for accelerator beam diagnosis in the prior art, form beam diagnosis detection based on magnetic modulation, and achieve high-precision weak current detection of the accelerator.

[0005] The present invention provides a magnetic probe for diagnosing weak beam currents in an accelerator, which includes a magnetic core ring group, a coil winding, and a multi-core connector. The magnetic core ring group includes an excitation magnetic core ring, a compensation magnetic core ring, and a detection magnetic core ring arranged in parallel. The coil winding 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 around the excitation magnetic core ring, the excitation compensation coil is wound around the compensation magnetic core ring, the AC detection coil is wound around the detection magnetic core ring, and the residual ripple detection coil and the current compensation coil are simultaneously wound around the excitation magnetic core ring, the compensation magnetic core ring, and the detection magnetic core ring. The multi-core connector includes multiple signal transmission ports, 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 the magnetic probe for diagnosing weak beam currents in an accelerator provided by the present invention, the magnetic core ring group includes two sets of the excitation magnetic core rings, one set of the compensation magnetic core rings, and one set of the detection magnetic core rings. The coil winding includes two sets of the excitation coils, two sets of the excitation detection coils, one set of the excitation compensation coils, one set of the AC detection coils, one set of the residual ripple detection coils, and one set of the current compensation coils.

[0007] The two sets of the excitation coils are correspondingly wound around the two sets of the excitation magnetic core rings, and the number of turns of the two sets of the excitation coils is the same and the directions are opposite. The two sets of the excitation detection coils are correspondingly wound around the two sets of the excitation magnetic core rings, and the number of turns of the two sets of the excitation detection coils is the same and the directions are the same. The residual ripple detection coil is sequentially wound around the two sets of the excitation magnetic core rings, one set of the compensation magnetic core rings, and one set of the detection magnetic core rings, and the number of turns on each magnetic core ring is equal and the directions are the same. The current compensation coil is sequentially wound around the two sets of the excitation magnetic core rings, one set of the compensation magnetic core rings, and one set of the detection magnetic core rings, and the number of turns on each magnetic core ring is equal and the directions are the same.

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

[0009] A magnetic probe for diagnosing weak beam currents in an accelerator according to the present invention. The magnetic probe for diagnosing weak beam currents in an accelerator further includes a coaxial vacuum inner tube and a vacuum outer tube. Both 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 disposed in the vacuum-sealed cavity, and the multi-core connector passes through the vacuum outer tube.

[0010] A magnetic probe for diagnosing weak beam currents in an accelerator according to the present invention. A magnetic shielding layer is provided on the inner wall of the vacuum outer tube and on the end surface of the sealing flange facing the vacuum-sealed cavity.

[0011] A magnetic probe for diagnosing weak beam currents in an accelerator according to 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 diagnosing weak beam currents in an accelerator, including the magnetic probe for diagnosing weak beam currents in an accelerator according to any one of the above, and further including a controller. The controller is connected to the multi-core connector of the magnetic probe through a connection cable. The controller includes an excitation generator, an excitation detection and 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 connection 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 and compensation module is connected to the excitation detection coil of the magnetic probe through the connection cable, and is used to detect the difference in the excitation magnetic flux generated in the excitation coil; the other end of the excitation detection and compensation module is connected to the excitation compensation coil of the magnetic probe through the connection 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 connection cable, and is used to detect and extract the second harmonic in the excitation detection coil as the DC component in the to-be-detected primary weak current signal; the AC detection module is connected to the AC detection coil of the magnetic probe through the connection cable, and is used to extract the AC component in the to-be-detected primary weak current signal; the residual ripple detection module is connected to the residual ripple detection coil of the magnetic probe through the connection cable, and is used to extract the difference between the magnetic flux generated by the to-be-detected primary weak current 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 perform 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, 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 connection 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 beam diagnosis provided by the present invention, the controller further includes a power amplification module, and the power amplification module 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.

[0015] According to a detection device for accelerator weak beam diagnosis provided by the present invention, the controller further includes a gear selection module, and the gear selection module is connected to the power amplification module, and is used to control the gain of the power amplification module under different to-be-detected weak current ranges so that the power amplification module outputs a signal with the best signal-to-noise ratio.

[0016] The present invention also provides a detection method for accelerator weak beam diagnosis, which is applicable to the detection device for accelerator weak beam diagnosis described in any one of the above, and the detection method for accelerator weak beam diagnosis includes:

[0017] 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 making the excitation core of the excitation core ring alternately reach the saturation state.

[0018] 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 so that the entire excitation core ring externally presents a zero magnetic flux state.

[0019] 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.

[0020] 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, the signal processing module performs phase-locked, filtering, and gain amplification processing and outputs a total error signal.

[0021] The power amplification 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 amplification module to change the gain through the gear selection module so that the power amplification module outputs a signal with the best signal-to-noise ratio.

[0022] The output module detects the current value in the current compensation coil, converts the detected current value into an analog voltage value for output, and obtains the weak current detection result in the oscilloscope.

[0023] The magnetic probe for accelerator weak current beam diagnosis provided by the present invention consists of a core ring group composed of multiple core rings with different functions and a coil winding composed of multiple coils with different functions. Based on different functions, the corresponding coils are wound around the core rings to form a feedback and compensation design with multiple weak magnetic flux differences, which can improve the detection accuracy to the order of dozens of microamperes to achieve high-precision weak DC detection of the accelerator. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is a schematic cross-sectional structure diagram of a magnetic probe for weak beam diagnosis of an accelerator provided by the present invention.

[0026] Figure 2 It is a schematic connection structure diagram of a detection device for weak beam diagnosis of an accelerator provided by the present invention.

[0027] Figure 3 It is a schematic working principle diagram of a magnetic probe and a controller for weak beam diagnosis of an accelerator provided by the present invention.

[0028] Reference numerals:

[0029] 1. Magnetic core ring group; 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. Connection cable. Specific embodiments

[0030] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0032] 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 directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0033] In the embodiments of the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply indicates that the horizontal height of the first feature is less than that of the second feature.

[0034] In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments 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 a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0035] The following is combined with Figures 1 to 3 to describe the magnetic probe, detection device and detection method for weak beam diagnosis of an accelerator of the present invention.

[0036] An embodiment of the present invention provides a magnetic probe for weak beam diagnosis of an accelerator. Refer to Figure 1 As shown, the magnetic probe includes a magnetic core ring group 1, a coil winding 2 and a multi-core connector 3. The magnetic core ring group 1 includes an excitation magnetic core ring, a compensation magnetic core ring and a detection magnetic 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 around the excitation magnetic core ring, the excitation compensation coil is wound around the compensation magnetic core ring, the AC detection coil is wound around the detection magnetic core ring, and the residual ripple detection coil and the current compensation coil are respectively and simultaneously wound around the excitation magnetic core ring, the compensation magnetic core ring and the detection magnetic 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.

[0037] It can be understood that during the beam diagnosis of proton and heavy ion accelerators, high-sensitivity equipment is required to detect the measurement of "weak currents" in the microampere level or even lower levels. This magnetic probe for weak beam diagnosis of accelerators in this embodiment forms a magnetic core ring group 1 through multiple magnetic core rings with different functions, and forms a coil winding 2 through multiple coils with different functions. Based on different functions, the corresponding coils are wound around the magnetic core rings to form a feedback and compensation design with multiple weak magnetic flux differences, which can improve the detection accuracy to the order of dozens of microamperes to achieve high-precision weak direct current detection of accelerators.

[0038] In some embodiments of the magnetic probe for weak beam diagnosis of accelerators of the present invention, the magnetic core ring group 1 includes two excitation magnetic core rings, one compensation magnetic core ring, and one detection magnetic core ring; the coil winding 2 includes two excitation coils, two excitation detection coils, one excitation compensation coil, one alternating current detection coil, one residual ripple detection coil, and one current compensation coil.

[0039] The two excitation coils are correspondingly wound around the two excitation magnetic core rings, and the number of turns of the two excitation coils is the same and the directions are opposite; the two excitation detection coils are correspondingly wound around the two excitation magnetic core rings, and the number of turns of the two excitation detection coils is the same and the directions are the same; the residual ripple detection coil is sequentially wound around the two excitation magnetic core rings, one compensation magnetic core ring, and one detection magnetic core ring, and the number of turns on each magnetic core ring is equal and the directions are the same; the current compensation coil is sequentially wound around the two excitation magnetic core rings, one compensation magnetic core ring, and one detection magnetic core ring, and the number of turns on each magnetic core ring is equal and the directions are the same.

[0040] 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.

[0041] 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.

[0042] Further, in some other embodiments of the magnetic probe for weak beam diagnosis of an accelerator in the present invention, the coil winding 2 further includes a calibration coil. The calibration coil is wound around the excitation magnetic core ring, the compensation magnetic core ring, and the detection magnetic core ring simultaneously. The two ends of the calibration coil are externally connected to a standard current source. Specifically, the magnetic core ring group 1 includes a group of calibration coils, which are also wound around two groups of excitation magnetic core rings, a group of compensation magnetic core rings, and a group of detection magnetic core rings in sequence. The two ends of the calibration coil are connected to the output ports of a 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 result meets the expected requirements. The number of turns of the calibration coil on each magnetic core ring is equal and the direction is the same. The number of turns on each magnetic core ring is preferably but not limited to 10 turns, ensuring that the calibration current can uniformly affect each magnetic core ring, thereby improving the accuracy and consistency of calibration.

[0043] The high-precision standard current source is an external current source that provides high-precision current output with an accuracy within 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, according to the calibration requirements, one or more standard current values are selected for testing. The output ports of the high-precision standard current source are connected to the two ends of the calibration coil, and 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 at one time to ensure that there is no other current interference during the calibration process, otherwise it will affect the accuracy of the calibration result.

[0044] In some embodiments of the magnetic probe for weak beam diagnosis of an accelerator in the present invention, continue to refer to Figure 1 As shown, the magnetic probe for weak beam diagnosis of an accelerator further includes a coaxial vacuum inner tube 4 and a vacuum outer tube 5. The two ends of the vacuum inner tube 4 and the vacuum outer tube 5 are respectively connected to a sealing flange 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 passes through the vacuum outer tube 5.

[0045] 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, ensuring that the space between the two tubes is completely sealed, thereby forming a vacuum environment. Key components such as the magnetic core ring group 1 and the coil winding 2 are arranged 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 signals. The multi-core connector 3 passes through the vacuum outer tube, allowing signals to be transmitted from the internal magnetic core ring group 1 and coil winding 2 to external devices for processing, ensuring both stable signal transmission and maintaining the vacuum tightness of the entire system.

[0046] The sealing flange 6 can be, but is not limited to, a 304 or 316LN type stainless steel standard CF flange. During the accelerator beam current diagnosis, the sealing flange 6 is used to connect to the upstream and downstream pipelines and perform vacuum sealing. The particle beam current in the proton or heavy ion accelerator flows through the vacuum inner tube 4 from the upstream and downstream pipelines via the sealing flange 6. During this process, the beam current diagnosis is detected by the magnetic core ring group 1 and the coil winding 2 between the vacuum inner tube 4 and the vacuum outer tube 5.

[0047] In some specific examples, magnetic shielding layers 7 are provided on the inner wall of the vacuum outer tube 5 and the end faces of the sealing flange 6 facing the vacuum sealed 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 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 coil winding 2 from unnecessary electromagnetic interference and ensure their normal operation. The magnetic shielding layer 7 can be made of high-permeability materials (such as permalloy or soft ferrite), and these materials have excellent magnetic shielding performance to avoid the leakage magnetic field of the upstream and downstream magnets of the accelerator affecting the magnetic core ring during operation. Figure 1 The arrow direction in [description] indicates the bypass direction of the mirror 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 cancelled by the mirror current signal of the vacuum pipeline inside the ring. The magnetic shielding layer 7 guides the external magnetic field around the magnetic core ring group 1 through its high-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.

[0048] Furthermore, the vacuum inner tube 4 includes a first vacuum tube and a second vacuum tube, and the first and second vacuum tubes are connected by a ceramic ring 8. The first vacuum tube is a part of the vacuum inner tube 4 and is 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 and is usually located at one end close to the downstream pipeline. The ceramic ring 8 is an intermediate component for connecting the first and second vacuum tubes. The ceramic ring 8 has excellent electrical insulation performance, which can effectively prevent the direct conduction of current between the two vacuum tubes and avoid short circuits or other electrical problems. In a high-vacuum environment, when the particle beam current passes through the vacuum pipeline, induced currents (image currents) will be generated on the pipeline wall, and these currents will interfere with the measurement of the weak beam current signal by the magnetic core ring group 1. Through its electrical insulation characteristics, the ceramic ring 8 cuts off the induced image current, preventing it from directly conducting along the vacuum pipeline wall. Instead, it bypasses the periphery of the magnetic core ring and transfers downward, thus avoiding the cancellation of the electromagnetic field signal generated by the image current and the primary weak current, thereby improving the measurement accuracy.

[0049] It should be understood that in some other embodiments of the magnetic probe for accelerator weak beam diagnosis of the present invention, it may only include three components: the magnetic core ring group 1, the coil winding 2, and the multi-core connector 3. After being treated by potting or the like to form an exposed magnetic probe, it can be applied to the outer wall of the vacuum pipeline or the test piece. Its application scenario is more flexible, but it is also more susceptible to environmental magnetic leakage and noise, etc.

[0050] On the other hand, the present invention also provides a detection device for accelerator weak beam diagnosis. Refer to Figure 2 As shown, in some embodiments, the detection device includes the magnetic probe for accelerator weak beam diagnosis according to any one of the above, and further includes a controller 9. The controller 9 is connected to the multi-core connector 3 of the magnetic probe through a connection cable 10. The controller 9 includes an excitation generator, an excitation detection and 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.

[0051] The excitation generator is connected to the excitation coil of the magnetic probe through the 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 and compensation module is connected to the excitation detection coil of the magnetic probe through the connecting cable 10, and is used to detect the difference in the excitation magnetic flux generated in the excitation coil; the other end of the excitation detection and compensation module is connected to the excitation compensation coil of the magnetic probe through the 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 the connecting cable 10, and is used to detect and extract the second harmonic in the excitation detection coil as the DC component in the measured primary weak current signal; 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 measured primary weak current signal; the residual ripple detection module is connected to the residual ripple detection coil of the magnetic probe through the connecting cable 10, and is used to extract the difference between the magnetic flux generated by the measured primary weak current 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 perform 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, 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 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.

[0052] It can be understood that the controller 9 is connected to the multi-core connector 3 of the magnetic probe through the connection cable 10 and is responsible for signal generation, processing, and output. The excitation generator outputs a square-wave excitation voltage with a fixed frequency to the excitation coil of the magnetic probe, generating an alternating magnetic field, which provides a basic signal source for subsequent magnetic field measurement. The input end of the excitation detection and 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 and compensation module ensures the stability and accuracy of the system by detecting and compensating the difference in 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, and uses it as the DC component in the measured primary weak current signal, separating the second-harmonic component in the high-frequency signal for extracting the DC component of the measured primary weak current and improving the measurement accuracy. The AC detection module is connected to the AC detection coil of the magnetic probe to extract the AC component in the measured primary weak current signal and separate the AC part in the measured signal for further analysis and processing. The residual ripple detection module is connected to the residual ripple detection coil of the magnetic probe to extract the difference between the magnetic flux generated by the measured primary weak current and the magnetic flux generated by the current compensation coil, forming a residual ripple component, detecting the residual ripple to evaluate the system error, and performing 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 a total error signal, and outputs a compensation current to the current compensation coil based on the total error signal, comprehensively processing various signals, eliminating noise and interference, and generating a high-precision measurement result. 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, converting the final measurement result into a voltage signal that is easy to read and use.

[0053] The working process of this detection device for weak beam diagnosis in an accelerator mainly includes processes such as excitation signal generation, signal detection and compensation, signal processing and compensation, and result output.

[0054] Excitation signal generation: The excitation generator outputs a square-wave excitation voltage with a fixed frequency to the excitation coil, generating an alternating magnetic field.

[0055] Signal detection and compensation: The excitation detection and compensation module detects the difference in magnetic flux in the excitation coil and injects a 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 measured primary weak current. The AC detection module extracts the AC component of the measured primary weak current. The residual ripple detection module detects the difference in magnetic flux between the measured primary weak current and the current compensation coil, forming a residual ripple component.

[0056] Signal processing and compensation: The signal processing module performs phase-locking, filtering, and gain amplification on the above various signals to generate a total error signal and output a compensation current to the current compensation coil.

[0057] Result output: The output module converts the current value in the current compensation coil into an analog voltage value for output.

[0058] This detection device for weak beam diagnosis of accelerators in this embodiment realizes high-precision measurement of weak beams of accelerators through precise design and the collaborative work of multiple modules, and is applicable to the weak beam current diagnosis requirements in complex environments such as proton or heavy ion accelerators. Through a variety of signal processing technologies, the high accuracy and stability of the measurement results are ensured. Through signal compensation and shielding design, the influence of external electromagnetic interference on the measurement results is reduced.

[0059] In some embodiments of the detection device for weak beam diagnosis of accelerators of the present invention, the controller 9 further includes a power amplification module. The power amplification module 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 amplification module is located between the signal processing module and the current compensation coil. Its input end receives the total error signal output from the signal processing module. After power amplification processing, a compensation current is output from the output end to the current compensation coil. The power amplification 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 errors in the system and maintain high-precision measurement. By amplifying the signal, even in the case of weak beams, a sufficient signal-to-noise ratio can be obtained, improving the sensitivity and reliability of the system.

[0060] Furthermore, the controller 9 further includes a gear selection module. The gear selection module is connected to the power amplification module and is used to control the gain of the power amplification module under different weak beam ranges to be measured, so that the power amplification module outputs a signal with the best signal-to-noise ratio. The gear selection module is connected to the power amplification module. When the superconducting linear accelerator is in weak beam commissioning and normal operation, and when the synchrotron ring accelerator is in multi-turn accumulation and frequency conversion acceleration, the beam current to be measured will change greatly by several orders of magnitude. Therefore, it is necessary to control the power amplification module to perform corresponding gain changes to ensure that a signal with the best signal-to-noise ratio is output. The power amplification module is controlled to dynamically adjust the gain of the power amplification module according to different weak beam ranges to be measured. Under different weak beam ranges to be measured, the appropriate gain setting is automatically selected to ensure the best signal-to-noise ratio. By intelligently selecting the gain gear, measurement errors caused by too strong or too weak signals are avoided, and the overall performance and stability of the system are improved.

[0061] In this embodiment, the power amplification module ensures that the intensity of the compensation current is large enough to effectively cancel out the system error and improve the measurement accuracy. The gain is adjusted according to different ranges through the range selection module, avoiding measurement errors caused by too strong or too weak signals and ensuring the best signal-to-noise ratio. Multi-stage signal processing and gain adjustment are formed, reducing the influence of external electromagnetic interference on the measurement results and improving the stability and reliability of the system.

[0062] On the other hand, the present invention also provides a detection method for accelerator weak beam diagnosis, which is applicable to the detection device for accelerator weak beam diagnosis in any of the above embodiments. The detection method for accelerator weak beam diagnosis includes the following steps S1 to S6.

[0063] 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 making the excitation core of the excitation core ring alternately reach the saturation state.

[0064] S2. 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 to make the entire excitation core ring externally present a zero magnetic flux state.

[0065] 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 measured primary weak current signal, and the signal is output to the signal processing module; based on the AC detection module, the AC component in the measured primary weak current signal 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 measured primary weak current 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.

[0066] 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.

[0067] S5. The power amplification 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. During this process, the range selection module controls the power amplification module to change the gain, so that the power amplification module outputs a signal with the best signal-to-noise ratio.

[0068] S6. The output module detects the current value in the current compensation coil, converts the detected current value into an analog voltage value for output, and obtains the weak current detection result on the oscilloscope.

[0069] See Figure 3Schematic diagram of the working principle of the magnetic probe and the controller shown. 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 the weak beam diagnosis of the accelerator in this embodiment includes the processes of excitation signal generation - excitation compensation - second harmonic demodulation - AC component extraction - residual ripple component extraction - signal processing - power amplification - gain adjustment - result output.

[0070] Excitation signal generation: The excitation generator of the controller 9 is connected to the excitation coils of the magnetic probe through the connection cable 10 and the multi-core connector 3, and outputs a square-wave excitation voltage with a fixed frequency to the excitation coils, so that the excitation coils generate an alternating excitation current, and the excitation magnetic cores of the excitation magnetic core rings reach the saturation state alternately, providing a basic signal source for subsequent magnetic field measurement, and ensuring that the system can accurately measure the weak primary current signal to be measured. The waveform of the excitation voltage is preferably a square wave, the frequency is preferably 31 kHz, and the voltage amplitude is preferably such that the excitation magnetic core can reach the saturation state alternately quickly. The square-wave voltage excitation source can make the key sensitivity parameters of the magnetic probe of the present invention not affected by the excitation field itself and not change with the signal field of the weak primary current to be measured, and has high independence and stability.

[0071] Excitation compensation: One end of the excitation detection and compensation module of the controller 9 is connected to the excitation detection coil, which is used to detect the difference in the excitation magnetic flux generated in the excitation coil, and the other end is connected to the excitation compensation coil, which is used to inject the excitation compensation current. The excitation detection coils, with equal number of turns and the same direction, are respectively wound on the excitation magnetic core rings, and are used to detect that when actually used, the magnetic flux magnitudes excited by the two excitation coils on the two excitation magnetic core rings are inconsistent, and thus when they cannot be completely cancelled out, the magnitude of the difference in this magnetic flux. The excitation compensation coil is separately wound on the compensation magnetic core ring, takes the excitation detection coil as the signal input, and the output signal is used to compensate for the magnetic flux difference of the excitation coil.

[0072] Based on the excitation detection and compensation module detecting the difference in the excitation magnetic flux generated by the excitation coil, and injecting the excitation compensation current into the excitation compensation coil, the magnetic flux difference in the excitation coil is eliminated through the compensation current, so that the overall excitation magnetic core ring presents a zero magnetic flux state to the outside, reducing the system error and ensuring the stability and accuracy of the system.

[0073] 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. Preferably but not limited to the use of second harmonic components for signal demodulation in the present invention, all even harmonic signals can also be used for demodulation. The essence of even harmonic magnetic modulation is that, by using the symmetric non-linear characteristics of the hysteresis loop of soft magnetic materials, when there are both an excitation field and a DC or low-frequency signal field at the same time, the signal field will cause the magnetic core to accelerate and saturate in advance in the first half cycle, and in the second half cycle, it will oppose the excitation field to make it saturate laggingly. The difference in the magnetic flux change rate between these two half cycles generates an even harmonic signal, and the presence of the signal field has little effect on odd harmonics.

[0074] Based on the second harmonic demodulation module, the second harmonics in the excitation detection coil are detected and extracted, and the second harmonic components in the high-frequency signal are separated, which are used to extract the DC component of the primary weak current to be measured, improve the measurement accuracy, and ensure the accurate extraction of the DC component.

[0075] AC component extraction: The AC detection module of the controller 9 is connected to the AC detection coil and is used to extract the AC component in the primary weak current signal to be measured. The AC detection coil is separately wound on the detection magnetic core ring and is used to pick up the AC component in the weak current signal to be measured. 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. The AC detection module separates the AC part in the signal to be measured, which is convenient for further analysis and processing, ensures the accurate extraction of the AC component, and provides basic data for further signal processing.

[0076] 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 primary 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 magnetic core ring, the compensation magnetic core ring, and the detection magnetic core ring and is used to pick up the magnitude of this residual ripple and output the signal 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 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.

[0077] Signal Processing: The signal processing module of controller 9 is connected to the second harmonic demodulation module, AC detection module, and residual ripple detection module. 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, the signal processing module performs phase-locking, filtering, and gain amplification processing, and outputs the 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 signals, and provides reliable data for subsequent compensation.

[0078] Power Amplification: The power amplification module of controller 9 is connected to the signal processing module and the current compensation coil, and is used to perform power amplification processing on the input total error signal and output the compensation current to the current compensation coil. The current compensation coil is wound around the excitation core ring, compensation core ring, and detection core ring, and is used to transmit the processed and amplified compensation current to ensure a zero magnetic flux state within the entire measurement space. The power amplification module performs power amplification processing based on the total error signal output by the signal processing module and outputs the compensation current to the current compensation coil, enhancing the intensity of the compensation current to ensure that it is strong enough to cancel out the system error, improving the sensitivity and reliability of the system, and ensuring high-precision measurement.

[0079] Gain Adjustment: The range selection module of controller 9 is connected to the power amplification module and is used to control the gain of the power amplification module under different weak flow ranges to be measured, enabling the measurement system to change the range and maintain the best signal-to-noise ratio. The range control module is used when the superconducting linear accelerator is in weak flow commissioning and normal operation, and when the synchrotron ring accelerator is in multi-turn accumulation and frequency conversion acceleration, the measured beam current will change by several orders of magnitude, so it is necessary to control the power amplification module to perform corresponding gain changes to ensure the output of a signal with the best signal-to-noise ratio. The range selection module dynamically adjusts the gain of the power amplification 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 over-strong or over-weak signals.

[0080] Result Output: The output module of controller 9 is connected to the current compensation coil and is used to detect the current value in the current compensation coil and convert this current value into an analog voltage value for output to obtain the weak current detection result on the oscilloscope. The output module converts the final measurement result into a voltage signal that is easy to read and use, facilitating users to view and analyze the measurement results, and ensuring the intuitiveness and operability of the data.

[0081] 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 detection method, the accuracy detection is first carried out through the calibration coil. Before calibration, it is necessary to ensure that the primary weak current is zero. Then, the output port of the high-precision standard current source is connected to both ends of the calibration coil, and a standard current is injected into the calibration coil through the high-precision standard current source to generate a corresponding magnetic field in the calibration coil. A process similar to the above detection method is adopted (specifically, the accuracy calibration process of the current sensor in the prior art can be referred to), the output value of the controller output module is recorded, and the actual output value is compared with the theoretical value to evaluate whether the weak current detection accuracy of the detection device meets the requirements.

[0082] The detection method for accelerator weak current beam diagnosis of the present invention will be described below in combination with the test results of specific examples. It should be noted that the magnetic probe used in this example only includes three components: the magnetic core ring group 1, the coil winding 2, and the multi-core connector 3, and is processed into a bare magnetic probe through processes such as potting, without including components such as the vacuum inner tube 4, the vacuum outer tube 5, the magnetic shielding layer 7, and the sealing flange 6. The system noise and background measured in this example will be relatively larger.

[0083] Specifically, when using the standard current source meter Keithley6221 to input a square wave current of 120 µA, 100 Hz, and 50% duty cycle through the calibration coil, the oscilloscope measures that the voltage signal output by the controller 9 at 20 mA / 10 V is approximately 60 mV. After conversion by the gear, it is 120 µA. At this time, the noise width is approximately 60 µA, and there is still a signal-to-noise ratio of about 2. At this time, because it is a bare magnetic ring test without a magnetic shielding structure, it will be interfered by the 50 Hz power supply noise, etc. It is easier to measure weak DC or low-frequency signals in the order of dozens of microamperes with a complete shielded magnetic probe, which can meet the detection requirements of accelerator weak current beam diagnosis.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A magnetic probe for weak beam diagnosis of an accelerator, characterized in that, Comprising: A magnetic core ring group (1), the magnetic core ring group (1) comprising two sets of excitation magnetic core rings arranged in parallel, one set of compensation magnetic core rings, and one set of detection magnetic core rings; A coil winding (2), the coil winding (2) comprising two sets of excitation coils, two sets of excitation detection coils, one set of excitation compensation coils, one set of AC detection coils, one set of residual ripple detection coils, and one set of current compensation coils. The two sets of excitation coils are respectively wound around the two sets of excitation magnetic core rings, and the number of turns of the two sets of excitation coils is the same and the directions are opposite; the two sets of excitation detection coils are respectively wound around the two sets of excitation magnetic core rings, and the number of turns of the two sets of excitation detection coils is the same and the directions are the same; the excitation compensation coil is wound around the compensation magnetic core ring, the AC detection coil is wound around the detection magnetic core ring, the residual ripple detection coil is sequentially wound around the two sets of excitation magnetic core rings, one set of compensation magnetic core rings, and one set of detection magnetic core rings, and the number of turns on each magnetic core ring is equal and the directions are the same; the current compensation coil is sequentially wound around the two sets of excitation magnetic core rings, one set of compensation magnetic core rings, and one set of detection magnetic core rings, and the number of turns on each magnetic core ring is equal and the directions are the same; A multi-core connector (3), comprising 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).

2. The magnetic probe for weak beam diagnosis of an accelerator according to claim 1, characterized in that, The coil winding (2) further comprises a calibration coil, the calibration coil is simultaneously wound around the excitation magnetic core ring, the compensation magnetic core ring, and the detection magnetic core ring, and both ends of the calibration coil are externally connected to a standard current source.

3. The magnetic probe for weak beam diagnosis of an accelerator according to claim 1 or 2, characterized in that The magnetic probe for weak beam diagnosis of an accelerator further comprises a coaxial vacuum inner tube (4) and a vacuum outer tube (5), both ends of the vacuum inner tube (4) and the vacuum outer tube (5) are respectively connected to a sealing flange (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) passes through the vacuum outer tube (5).

4. The magnetic probe for weak beam diagnosis of an accelerator according to claim 3, 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 sealed cavity.

Images