A non-intercepting DC beam position and beam spot shape measurement method and system

Abstract

The present invention provides a non-intercepting DC beam position and beam spot shape measurement method and system, including: applying a voltage of a preset amplitude between each of two deflection plates facing each other in the measurement probe to generate an electric field between the two deflection plates; using the electric field to make the beam hit the current probe, thereby detecting the current change; zeroing the deflection plate voltage, adjusting the voltage of the deflection plate until the current is detected on the current probe, recording the voltage amplitude at this time, and looping the above operation for each group of deflection plates until the measurement is completed; processing the voltage amplitude with a preset logic, thereby obtaining the offset displacement, so as to obtain the beam position and the beam spot shape. The present invention solves the technical problems of complex structure, susceptibility to interference, high cost of use, easy damage and ablation, and single measurement object.

Description

Technical Field

[0001] The present invention relates to the technical field of accelerator beam diagnosis, and in particular to a non-intercepting direct current beam position and beam spot shape measurement method and system. Background Art

[0002] Beam position and beam spot shape are important parameters in the process of accelerator debugging, operation and acceptance. In order to ensure efficient and reliable particle transportation during the operation of the accelerator system and provide high-quality, high-brightness and stable beam for subsequent work, it is necessary to continuously optimize a series of beam parameters during system debugging and operation. Accurately and effectively realizing the collection and diagnosis of parameters such as beam position and beam spot shape can not only greatly save the beam debugging time and obtain better beam quality, but also effectively reduce the failure rate of accelerator operation and increase the service life of the accelerator.

[0003] The currently commonly used beam position diagnosis method mainly uses the detector to couple and measure the electromagnetic field of the beam. According to the principle of electromagnetic induction, when the beam is transmitted forward, a transverse electromagnetic field wave will be generated in the surrounding space. Placing corresponding electrodes around the beam pipe will induce a corresponding current and form an electromotive force. When the beam deviates in a certain direction, the induced potential generated by the electrode in that direction will increase, while the induced potential of the electrode in the opposite direction will decrease. Then, the direction and degree of the beam deviation can be measured by comparing the signals collected by the corresponding electrodes. This method is divided into three types according to the shape of the detector: button type, strip type and cavity beam position detector. This type of detector is usually complex in structure, susceptible to interference, and relatively expensive.

[0004] At present, the commonly used methods for measuring beam spot are optical measurement and wire scanning measurement. Optical measurement is usually an interception type measurement, and wire scanning measurement is also a quasi-non-interception type device. These two methods are not suitable for applications with high beam energy and high beam intensity, and are prone to damage and ablation.

[0005] Chinese patent specification CN103809198 discloses a method for measuring the beam position of a particle accelerator. This method integrates the electrode signals of multiple electrode probes into a matrix, and uses principal component analysis to simultaneously process these electrode signals, thereby eliminating the noise in each electrode signal and improving the measurement accuracy of the beam position. This method can only locate the beam position, but cannot provide relevant information about the beam spot shape.

[0006] Chinese patent specification CN109490943 discloses a cross-multi-wire probe for measuring ion beam current intensity and position. The probe has the characteristics of simple structure, convenient processing, high reliability and low cost, and can measure beam current intensity, beam position and beam profile information respectively. This method belongs to quasi-non-interception measurement, and it is easy to cause probe ablation when the beam intensity is large. The existing technology has the technical problems of complex structure, susceptibility to interference, high cost of use, easy damage and ablation, and single measurement object. Summary of the invention

[0007] The technical problem to be solved by the present invention is how to solve the technical problems of complex structure, susceptibility to interference, high cost of use, easy damage and ablation, and single measurement object.

[0008] The present invention adopts the following technical solution to solve the above technical problem: a non-intercepting DC beam position and beam spot shape measurement method comprises:

[0009] S1. applying a voltage of a preset amplitude between two deflection plates facing each other in the measuring probe, so as to generate an electric field between the two deflection plates;

[0010] S2, using the electric field to make the beam hit the current probe, thereby detecting the current change;

[0011] S3, returning the voltage of the deflection plates to zero, adjusting the voltage of the deflection plates until the current is detected on the current probe, recording the voltage amplitude at this time, and repeating the above operation for each group of the deflection plates until the measurement is finished;

[0012] S4 processes the voltage amplitude with a preset logic to obtain an offset displacement, thereby obtaining the beam position and the beam spot shape.

[0013] The purpose of applying pulse voltage in the present invention is to reduce the influence of measurement on beam current on the one hand, and to avoid ablation of the probe by beam current when the current is strong on the other hand. The pulse electric field technology and the current probe technology are used to accurately detect the beam position, and the disturbance to the beam current is small during the measurement process. In addition, the method is simple in principle, easy to implement, and has low manufacturing cost. The present invention has the characteristics of simple structure, high reliability, and low cost, and can simultaneously measure information such as beam position and beam spot size.

[0014] In a more specific technical solution, step S2 includes:

[0015] S21, arranging the deflection plate and the current probe in a preset position relationship;

[0016] S22, applying the electric field to the beam so that the moving direction of the beam is offset toward the deflection plate on one side;

[0017] S23. When the applied voltage amplitude reaches a preset specific value, the beam will be projected onto the current probe on the corresponding side, so that the current change can be detected by using the current probe.

[0018] The present invention applies a voltage of a certain amplitude between each of the two deflection plates facing each other to generate an electric field between the two deflection plates. Under the action of the electric field, the beam will deviate in its moving direction toward one of the deflection plates. When the applied voltage amplitude reaches a certain value, the beam will just hit the current probe on the corresponding side, and the current change can be detected on the probe. The purpose of applying the pulse voltage is to reduce the influence of the measurement on the beam on the one hand, and to avoid the ablation of the probe by the beam when the current is strong on the other hand.

[0019] In a more specific technical solution, step S1 includes:

[0020] S11, arranging at least two groups of deflection plates opposite to each other, so that each group of deflection plates is arranged in a circle with a preset symmetry center as an axis;

[0021] S12, placing the current probe at a preset distance from the deflection plate.

[0022] In a more specific technical solution, step S3 includes:

[0023] S31, zeroing the deflection plate;

[0024] S32, adjusting the voltage of a group of the deflection plates, gradually increasing the voltage amplitude on the deflection plates until the current is detected on the current probe;

[0025] S33, stop adjusting the voltage amplitude, record the current voltage amplitude and execute steps S1 to S33 for the deflection plates of other groups.

[0026] In a more specific technical solution, step S31 includes:

[0027] S31, returning the current deflection plate voltage to zero;

[0028] S32, detecting the corresponding probe status and performing zeroing adjustment.

[0029] In a more specific technical solution, step S33 includes:

[0030] S331, clearing the current deflection plate voltage;

[0031] S332, switching to another group of the deflection plates and repeating the above operation to collect the voltage amplitude corresponding to each group of the deflection plates.

[0032] In a more specific technical solution, step S4 includes:

[0033] S41, processing the voltage amplitude corresponding to each group of the deflection plates with a preset offset displacement processing logic to obtain the offset displacement of the particle;

[0034] S42, processing the offset displacement with a preset deviation logic;

[0035] S43, obtaining the beam position and the beam spot shape according to the offset displacement processing.

[0036] In a more specific technical solution, step S41 includes:

[0037] According to the voltage amplitudes V1, V2...V i , the offset displacement S is calculated using the following logic i :

[0038] ,

[0039] Wherein, D is the distance between the deflection plate and the probe, L is the length of the deflection plate, d is the distance between the two deflection plates, and E is the incident beam energy.

[0040] In a more specific technical solution, step S43 includes:

[0041] S431, processing the offset displacement according to the following logic:

[0042] ,

[0043] The arrangement angle information of the combined deflection plates and the distance of the beam from the axis in the corresponding direction are obtained accordingly;

[0044] S432, obtaining arrangement angle information of the deflection plates;

[0045] S433, obtaining the beam spot shape and the beam position according to the arrangement angle information and the distance from the axis.

[0046] The present invention combines the arrangement angle information of the deflection plate to obtain the shape and size of the beam spot and determine the center position of the beam. The shape of the beam spot can be quantitatively estimated using the existing pulsed electric field technology and current probe technology. The disturbance to the beam is small during the measurement process, and no water cooling and heat dissipation treatment is required.

[0047] In a more specific technical solution, a non-intercepting direct current beam position and beam spot shape measurement system includes: an electric field generating unit, including at least two pairs of deflection plates and probes, for applying a voltage of a preset amplitude between each two opposite deflection plates in the measurement probe, so as to generate an electric field between the two deflection plates;

[0048] A detection unit, used for making the beam hit the current probe by the electric field, so as to detect the current change;

[0049] A voltage amplitude detection unit, used to reset the voltage of the deflection plates to zero, adjust the voltage of the deflection plates until the current is detected on the probe, record the voltage amplitude at this time, and repeat the above operation for each group of the deflection plates until the measurement is finished;

[0050] The beam position and beam spot shape processing unit is used to process the voltage amplitude according to a preset logic, thereby obtaining an offset displacement to obtain the beam position and the beam spot shape.

[0051] Compared with the prior art, the present invention has the following advantages: the purpose of applying pulse voltage in the present invention is to reduce the influence of measurement on the beam on the one hand, and to avoid the ablation of the probe by the beam when the current is strong on the other hand. The pulse electric field technology and the current probe technology are used to accurately detect the beam position, and the disturbance to the beam is small during the measurement process. Moreover, the principle of the method is simple, easy to implement, and the manufacturing cost is low. The present invention has the characteristics of simple structure, high reliability, and low cost, and can simultaneously measure information such as the beam position and beam spot size. The present invention applies a voltage of a certain amplitude between each of the two deflection plates facing each other to generate an electric field between the two deflection plates. Under the action of the electric field, the direction of movement of the beam will deviate to one side of the deflection plate. When the applied voltage amplitude reaches a certain specific value, the beam will just hit the current probe on the corresponding side, and the current change can be detected on the probe at this time. The present invention combines the arrangement angle information of the deflection plate to obtain the shape and size of the beam spot and determine the center position of the beam. The existing pulsed electric field technology and current probe technology can be used to quantitatively estimate the shape of the beam spot. During the measurement process, the disturbance to the beam is small and no water cooling is required. This solves the technical problems of the existing technology, such as complex structure, susceptibility to interference, high cost, easy damage and ablation, and single measurement object. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a flow chart of the beam position and beam spot shape measurement method;

[0053] Figure 2 This is a schematic diagram of the specific process in step S3 in Example 1;

[0054] Figure 3 It is a schematic diagram of the lateral structure of the measuring probe;

[0055] Figure 4 This is a cross-sectional view in the vertical direction of the measuring probe beam. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments 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.

[0057] Example 1

[0058] The beam position and beam spot shape measurement method of the present invention is carried out according to the following steps:

[0059] like Figure 3 As shown in the figure, a pulse voltage with a variable amplitude can be applied between each pair of deflection plates to deflect the beam; the current probe can detect the deflected beam hitting the probe. The entire detection system consists of n pairs of deflection plates and n pairs of probes. The deflection plates are arranged in a circle with the symmetry center as the axis, and the corresponding probes are placed at a certain distance behind the deflection plates.

[0060] Define the pulse voltage amplitude applied to both ends of the deflection plate as V i , i represents the serial number of each deflection plate.

[0061] Obtaining the deflection plate pulse voltage value

[0062] like Figure 1 and Figure 4 As shown, S1, a voltage of a certain amplitude is applied between each of the two deflection plates facing each other to generate an electric field between the two deflection plates;

[0063] S2. Under the action of the electric field, the beam will move toward the deflection plate on one side. When the applied voltage amplitude reaches a certain value, the beam will hit the current probe on the corresponding side. At this time, the current change can be detected on the probe. The purpose of applying pulse voltage is to reduce the influence of measurement on the beam on the one hand, and to avoid the ablation of the probe by the beam when the current is strong on the other hand.

[0064] like Figure 2 As shown, S3, at the beginning of the measurement, firstly, the deflection plate voltage is reset to zero, the corresponding probe state is detected, and the reset adjustment is performed; then, the voltage of one group of deflection plates is adjusted, and the voltage amplitude on the deflection plate is gradually increased, and the current change on the probe is observed at the same time. When the current is detected on the probe, the voltage amplitude adjustment is stopped, and the voltage amplitude at this time is recorded. After the recording is completed, the deflection plate voltage is reset to zero, and the other group of deflection plates is switched to repeat the above operation until all the deflection plates have completed the rotation, and the measurement is ended. Step S3 includes:

[0065] S31, bias voltage returns to zero;

[0066] S32, pulse bias is applied to beam deflection plate i;

[0067] S33, detecting the current of probe i;

[0068] S34, judging whether the current of probe i is greater than 0;

[0069] S35, if yes, then record the bias value V i ;

[0070] S36, if not, increase the bias value and return to step S33;

[0071] S37, judging whether i is greater than the total number of deflection plates;

[0072] S38, if yes, then combine the bias plate position and bias value V i Draw the beam spot shape;

[0073] S39: If not, then loop through steps S32 to S37.

[0074] Step 2: Processing of collected data

[0075] Based on the above measurement, we can get i groups of voltage amplitudes V1, V2…V i . Using the formula for particle deflection in an electric field

[0076]

[0077] We can calculate the particle displacement S i , where D is the distance between the deflection plate and the probe; L is the length of the deflection plate; d is the distance between the two deflection plates, and E is the incident beam energy. Furthermore, we can obtain the distance that the beam deviates from the axis in the corresponding direction: Combined with the arrangement angle information of the deflection plate, the shape and size of the beam spot can be obtained, and the center position of the beam can be determined.

[0078] In summary, the purpose of applying pulse voltage in the present invention is to reduce the influence of measurement on the beam on the one hand, and to avoid the ablation of the probe by the beam when the current is strong on the other hand. The pulse electric field technology and the current probe technology are used to accurately detect the beam position, and the disturbance to the beam is small during the measurement process. Moreover, the principle of this method is simple, easy to implement, and the manufacturing cost is low. The present invention has the characteristics of simple structure, strong reliability, and low cost, and can simultaneously measure information such as the beam position and the beam spot size. In the present invention, a voltage of a certain amplitude is applied between each of the two deflection plates facing each other to generate an electric field between the two deflection plates. Under the action of the electric field, the direction of movement of the beam will be offset to one side of the deflection plate. When the applied voltage amplitude reaches a certain value, the beam will just hit the current probe on the corresponding side, and the current change can be detected on the probe. The present invention combines the arrangement angle information of the deflection plate to obtain the shape and size of the beam spot and determine the center position of the beam. The shape of the beam spot can be quantitatively estimated by using the existing pulse electric field technology and current probe technology, and the disturbance to the beam is small during the measurement process, and no water cooling and heat dissipation treatment is required. The invention solves the technical problems of the prior art such as complex structure, susceptibility to interference, high cost of use, easy damage and ablation, and single measuring object.

[0079] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. 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 non-intercepting DC beam position and beam spot shape measurement method, characterized in that: include: S1. applying a voltage of a preset amplitude between two deflection plates facing each other in the measuring probe, so as to generate an electric field between the two deflection plates; S2, using the electric field to make the beam hit the current probe, thereby detecting the current change; S3, returning the voltage of the deflection plates to zero, adjusting the voltage of the deflection plates until the current is detected on the current probe, recording the voltage amplitude at this time, and repeating the above operation for each group of the deflection plates until the measurement is finished; S4. Processing the voltage amplitude with a preset logic to obtain an offset displacement, thereby obtaining the beam position and the beam spot shape.

2. A non-intercepting DC beam position and beam spot shape measurement method according to claim 1, characterized in that: The step S2 comprises: S21, arranging the deflection plate and the current probe in a preset position relationship; S22, applying the electric field to the beam so that the moving direction of the beam is offset toward the deflection plate on one side; S23. When the applied voltage amplitude reaches a preset specific value, the beam will be projected onto the current probe on the corresponding side, so that the current change can be detected by using the current probe.

3. The non-intercepting DC beam position and beam spot shape measurement method according to claim 1, characterized in that: The step S1 comprises: S11, arranging at least two groups of deflection plates opposite to each other, so that each group of deflection plates is arranged in a circle with a preset symmetry center as an axis; S12, placing the current probe at a preset distance from the deflection plate.

4. The non-intercepting DC beam position and beam spot shape measurement method according to claim 1, characterized in that: The step S3 comprises: S31, zeroing the deflection plate; S32, adjusting the voltage of a group of the deflection plates, gradually increasing the voltage amplitude on the deflection plates until the current is detected on the current probe; S33, stop adjusting the voltage amplitude, record the current voltage amplitude and execute steps S1 to S33 for the deflection plates of other groups.

5. The non-intercepting DC beam position and beam spot shape measurement method according to claim 4, characterized in that: The step S31 comprises: S31, returning the current deflection plate voltage to zero; S32, detecting the corresponding probe status and performing zeroing adjustment.

6. A non-intercepting DC beam position and beam spot shape measurement method according to claim 4, characterized in that: The step S33 comprises: S331, clearing the current deflection plate voltage; S332, switching to another group of the deflection plates and repeating the above operation to collect the voltage amplitude corresponding to each group of the deflection plates.

7. The non-intercepting DC beam position and beam spot shape measurement method according to claim 1, characterized in that: The step S4 comprises: S41, processing the voltage amplitude corresponding to each group of the deflection plates with a preset offset displacement processing logic to obtain the offset displacement of the particle; S42, processing the offset displacement with a preset deviation logic; S43, obtaining the beam position and the beam spot shape according to the offset displacement processing.

8. The non-intercepting DC beam position and beam spot shape measurement method according to claim 7, characterized in that: The step S41 comprises: According to the voltage amplitudes V1, V2...V i， The offset displacement S is calculated using the following logic: i : ， Wherein, D is the distance between the deflection plate and the probe, L is the length of the deflection plate, d is the distance between the two deflection plates, and E is the incident beam energy.

9. The non-intercepting DC beam position and beam spot shape measurement method according to claim 7, characterized in that: The step S43 comprises: S431, processing the offset displacement according to the following logic: ， The arrangement angle information of the combined deflection plates and the distance of the beam from the axis in the corresponding direction are obtained accordingly; S432, obtaining arrangement angle information of the deflection plates; S433, obtaining the beam spot shape and the beam position according to the arrangement angle information and the distance from the axis.

10. A non-intercepting DC beam position and beam spot shape measurement system, characterized in that: include: An electric field generating unit, comprising at least two pairs of deflection plates and probes, for applying a voltage of a preset amplitude between each two opposite deflection plates in the measuring probe, so as to generate an electric field between the two deflection plates; A detection unit, used for making the beam hit the current probe by the electric field, so as to detect the current change; A voltage amplitude detection unit, used to reset the voltage of the deflection plates to zero, adjust the voltage of the deflection plates until the current is detected on the probe, record the voltage amplitude at this time, and repeat the above operation for each group of the deflection plates until the measurement is finished; The beam position and beam spot shape processing unit is used to process the voltage amplitude according to a preset logic, thereby obtaining an offset displacement to obtain the beam position and the beam spot shape.

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