JPH053100A - Betatron vibration measuring device of ring-form accelerator - Google Patents

Abstract

PURPOSE:To measure betatron vibrations in the vertical direction and in the horizontal direction simultaneously in a ring-form accelerator of an electron synchrotron or the like. CONSTITUTION:A normal phase of high-frequency wave is applied to the electrodes 14 and 15, of electrodes 14 to 17 for knockout driving; and an opposite phase of high-frequency wave is applied to the electrodes 16 and 17, so as to give a knocking force of the oblique direction including the vertical and the horizontal components to the electron beams 10. The position fluctuation in the vertical and the horizontal directions of the electron beams 10 by the kicking force is found by calculating the detecting signals of electrodes 21 to 24 for detecting by an operation means 29. By sweeping the frequency of the high-frequency signal from the low frequency in order, the peak values are shown on a spectrum analyzer 40 respectively at the places corresponding to the betatron vibration frequencies in the vertical direction and in the horizontal direction. Consequently, the betatron vibrations in the vertical direction and in the horizontal direction can be measured simultaneously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring betatron vibrations in a ring-shaped particle accelerator such as a synchrotron, which is capable of simultaneously measuring horizontal vibrations and vertical vibrations. ..

[0002]

2. Description of the Related Art In an electron synchrotron, an electron beam orbits while oscillating on a closed orbit in a beam duct. This is called betatron oscillation, which is an important factor for stably orbiting the electron beam. That is, there are betatron frequencies at which the orbit of the electron beam becomes unstable, and it is necessary to avoid this frequency for operation. Therefore, the betatron frequency is measured, and control is performed so as not to reach this unstable frequency.

An RF knockout method is a method for measuring the betatron frequency. This is to detect the amplitude when the electron beam is kicked by applying a high frequency voltage to the electrode in the beam duct to generate an electric field, and the amplitude increases when it resonates with the betatron oscillation. Then, the betatron frequency is obtained from the applied frequency at that time.

A conventional betatron frequency measuring device (tune monitor) using the RF knockout method is shown in FIG. In the ring-shaped beam duct 12 around which the electron beam 10 circulates, four knockout excitation electrodes 14 to 1 are provided.
7, the electrodes 14 and 15 are arranged on the upper left and right sides, and the electrodes 16 and 17 are arranged on the lower left and right sides, respectively. A high frequency signal for excitation is applied to the excitation electrodes 14 to 17 from the high frequency generation means 18. The frequency of this high-frequency signal can be variously changed.

In addition to the excitation electrodes 14 to 17, beam position detection electrodes 21 to 24 are arranged at upper, lower, left and right positions, respectively. The calculation means 20 detects the signal generated in each of the detection electrodes 21 to 24 by the passage of the electron beam 10,
The position of the electron beam 10 is measured based on this.

This chain monitor separately measures the betatron frequency in the horizontal direction and the betatron frequency in the vertical direction. That is, when measuring the vibration in the vertical direction, a positive phase high frequency wave is applied to the upper electrodes 14 and 15, and a negative phase high frequency wave is applied to the lower electrodes 16 and 17, as shown in FIG. Then, an electric field 26 in the vertical direction is generated to kick the electron beam 10 in the vertical direction. This operation is repeated while sweeping the frequency of the high frequency from the low frequency to the high frequency. When measuring horizontal vibration, a positive phase high frequency is applied to the left electrodes 14 and 17, and a negative phase high frequency is applied to the right electrodes 15 and 16 as shown in FIG. 3B. A horizontal electric field 26 is generated to kick the electron beam 10 in the horizontal direction. This operation is repeated while sweeping the frequency of the high frequency from the low frequency to the high frequency. The calculating means 20 of FIG. 2 detects each of the detection electrodes 21 at the time of vertical kick and horizontal kick.
From the detection signals of .about.24, the frequency of the high frequency in which the fluctuation of the electron beam position is the largest is obtained, and the betatron frequencies in the vertical direction and the horizontal direction are obtained.

[0007]

However, the conventional tune monitor cannot measure the betatron frequency in the vertical direction and the frequency in the horizontal direction at the same time, and the measurement takes a long time. SUMMARY OF THE INVENTION The present invention aims to solve the above-mentioned drawbacks of the prior art and provide a betatron vibration measuring device for a ring-shaped accelerator capable of simultaneously measuring vertical and horizontal betatron vibrations.

[0008]

SUMMARY OF THE INVENTION The present invention provides an excitation electrode arranged to give a kicking force including both horizontal and vertical components to a particle beam circulating in a beam duct, and this electrode. A detection electrode arranged to detect the vertical and horizontal positions of the particle beam at a position different from the above; a high-frequency generator for applying high frequencies of various frequencies to the excitation electrode; Arithmetic means for determining the magnitude of change in each of the vertical and horizontal positions of the particle beam from the detection output of the working electrode.

[0009]

According to the present invention, since the kick is performed by the kick force including both vertical and horizontal components with respect to the particle beam, the high frequency frequency is changed and the detection signal obtained from the detection electrode at that time is calculated. Thus, it is possible to simultaneously measure vertical and horizontal betatron vibrations.

[0010]

FIG. 1 shows an embodiment of the present invention. In the ring-shaped beam duct 12 around which the electron beam 10 circulates, four knock-out excitation electrodes 14 to 17 are arranged vertically and horizontally. These excitation electrodes 14 to
An excitation high-frequency signal is applied to the high-frequency generator 17 from the high-frequency generator 18. The frequency of this high-frequency signal can be variously changed.

The high frequency signal is transmitted to the electrode 1 as shown in FIG.
A positive phase is applied to the electrodes 4 and 15, and a negative phase is applied to the electrodes 16 and 17. As a result, an oblique electric field 26 is generated, and the electron beam 10 is kicked obliquely.

In FIG. 1, beam position detection electrodes 21 to 24 are arranged at positions different from the excitation electrodes 14 to 17 in the beam duct 12 at upper, lower, left and right positions, respectively.

A signal is generated in each of the detection electrodes 21 to 24 by the passage of the electron beam 10. The detection signals of the detection electrodes 21 and 23 in the vertical direction are input to the 180 ° power combiner 30 of the calculation means 29, and are added (that is, subtracted) by shifting the phase by 180 °, so that the vertical movement from the central orbit of the electron beam 10 is performed. An output corresponding to the amount of deviation in the direction can be obtained.
The detection signals of the left and right detection electrodes 22 and 24 are input to the 180 ° power combiner 32 of the calculation means 29,
The phases are shifted by 0 ° and added (that is, subtracted) to obtain an output according to the amount of deviation of the electron beam 10 from the central trajectory in the left-right direction.

The outputs of the 180 ° power combiners 30 and 32 are added by the power combiner 38 via the variable attenuators 34 and 36, respectively, and input to the spectrum analyzer 40 to display the output level for each frequency.

When using the tune monitor of FIG.
The high frequency generated by the high frequency generator 18 is sequentially swept from a low frequency to a high frequency. As a result, the electron beam 10 circulating in the beam duct 12
Receives a kick force diagonally. Then, the kick force becomes maximum when the high frequency corresponds to the betatron frequency in the vertical direction and the betatron frequency in the horizontal direction. Therefore, when the high frequency wave is swept once, a peak occurs at a position corresponding to the betatron frequency in each direction as shown in FIG. 5, so that the betatron frequency in both directions is simultaneously measured. If it is not known in which direction the two peaks correspond, it is determined by changing either one of the variable attenuators 34 and 36 to see which one of the peaks on the spectrum analyzer 40 moves. be able to.

[0016]

[Modification] The excitation electrodes are not limited to those shown in the above embodiment, and for example, two excitation electrodes 14 and 15 as shown in FIG.
Can be arranged diagonally and a high-frequency wave of a positive phase can be applied to one side and a high frequency wave of a reverse phase to the other side.

The present invention can be applied not only to the electron synchrotron but also to various ring-shaped accelerators.

[0018]

As described above, according to the present invention, the kicking force including both the vertical and horizontal components with respect to the particle beam is used. By calculating the obtained detection signal, the betatron oscillations in the vertical direction and the horizontal direction can be simultaneously measured.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional device.

3 is a front view showing a method of applying a high frequency to an excitation electrode in the apparatus of FIG.

4 is a front view showing a method of applying a high frequency to an excitation electrode in the apparatus of FIG.

5 is a diagram showing a display example on the spectrum analyzer 40 of FIG.

FIG. 6 is a front view showing another arrangement example of the excitation electrodes according to the present invention.

[Explanation of symbols]

 10 Electron Beam 12 Ring Beam Tact 14 to 17 Excitation Electrode 18 High Frequency Generation Means 21 to 24 Detection Electrode 29 Computing Means

Claims (1)

Claim: What is claimed is: 1. An excitation electrode arranged to give a kick force including both horizontal and vertical components to a particle beam circulating in a beam duct, and this electrode. Detection electrodes arranged to detect vertical and horizontal positions of the particle beam at different positions, high-frequency generation means for applying high frequencies of various frequencies to the excitation electrodes, and the detection electrodes And a calculation means for obtaining the magnitude of changes in the vertical and horizontal positions of the particle beam from the detection output of the betatron vibration measuring device for a ring-shaped accelerator.