JPS6313300A - Radio frequency cavity - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to increasing the current flow in the high frequency cavity of a storage ring.

[Conventional technology]

Figure 2 shows, for example, the International School of Particle Accelerators Op the “Etoile Majorana” Center for Scientific Culture, Ellis 10-22.
November 1976 (Proceedings of
the First Course of the E
international 5chool of
Particle Accelerators
of the Ettore Majorana”C
enter for 5 scientificCultu
re+Er1ce 10-22 November 1
976), in which 1 is an RF resonator (high frequency cavity), 2 is the direction of the electrolytic vector, 3 is the direction of the magnetic field vector, and 4 is the TM
1r.

5 is a mode absorption rod, and 5 is the trajectory of the particle beam.

In addition to the fundamental mode, T M lt is generated in the resonator 1 by the zero particle beam 5, the operation of which will be explained next.

Mode 2 or 3 is excited. At this time, the particles undergo a trajectory change in the X direction due to interaction with the magnetic field 3. In a ring-shaped particle accelerator, particles change their orbits in the It ends up.

To avoid this, conventional stabilization measures include TM. A mode absorber 4 is used.

T M r Io mode absorber 4 is T M + Io
Converts the energy of the mode into heat, TM,... It has the property of weakening modes and contributes to beam stabilization. The principle is as follows. The absorber 4 has T M r + o
The mode is arranged so that a part of the magnetic field passes through the absorber, and in this state, the absorber 4
Eddy currents are generated therein, and heat is generated due to the resistance of the absorber 4. That is, T M + +. The energy of the mode will be converted into heat.

[Problem that the invention seeks to solve]

Since the conventional high-frequency cavity stabilization means is configured as described above, in order to suppress the T M IIo mode, the absorber 4 must be inserted quite deeply into the resonator 1, and the fundamental wave There were problems such as having an impact on

The present invention has been made to solve the above-mentioned problems, and aims to provide a device that can stabilize the flow of a particle beam without substantially affecting the fundamental mode.

[Means for solving problems]

The high-frequency cavity according to the present invention includes a detection means for detecting the phase and intensity of a higher-order mode other than the fundamental mode in the cough cavity, and a phase opposite to the higher-order mode other than the fundamental mode according to the detection result of the detection means. - Excitation means for exciting higher-order modes of the same intensity into the cavity.

[Effect]

In this invention, the detection means detects the intensity and phase of a higher-order mode other than the fundamental mode, and the excitation means provides a higher-order mode having an opposite phase and the same degree as the higher-order mode, thereby lowering the higher-order mode.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 1 is an RF resonator (high frequency cavity), 6 is an RF
a fundamental wave excitation antenna installed inside the resonator 1;
7 is TM. Anti-phase mode excitation antenna, 8 is a high frequency search coil, 9 is a fundamental mode cut filter, 10
is a phase detector, 11 is an intensity detector, 12 is a TM, . 13 is an attenuator, 14 is a phase shifter, and 15 is a terminating resistor having infinite impedance for the fundamental wave.

Next, the operation will be explained.

First, the T M + Io mode excited by the beam current is detected by a search coil 8, the fundamental mode is cut off by a filter 9, and the phase 1 intensity is detected by a phase detector 10° and an intensity detector 11. Ru.

Then, the phase shifter 14 adjusts the phase of the external TM110 oscillator 12 by the output of the phase detector 10, and adjusts the phase of the external TM110 oscillator 12 by the beam current. Excite waves that are in opposite phase to the mode. Further, by adjusting the output of the oscillator to be equal to the output of the intensity detector 11 by the attenuator 13, the resonator 1
T M + + within. A mode having the same intensity and opposite phase as the mode is excited by the excitation antenna 7, and T M r + in the resonator 1 is generated. mode can be canceled. Furthermore, in this embodiment, since the circuit 15 having infinite impedance with respect to the fundamental wave is placed after the T M llo anti-phase mode excitation antenna 7, the fundamental wave mode is
M l+. It does not affect the oscillator 12.

In the above embodiment, the T M + 16 mode oscillator is separate from the fundamental mode oscillator, but the two may be the same, in which case modulation may be added to the fundamental mode. .

Further, in the above embodiment, the case where the higher-order mode other than the fundamental mode generated in the resonator is the T M + lo mode has been described, but the present invention can be applied to other modes as well, and the above-mentioned method can be applied. It has a similar effect. It is also possible to use more than one of the above systems for stabilization of multiple modes.

Further, in the above embodiment, infinite terminating resistors are arranged in series to prevent coupling between power sources, but a directional coupler or a circulator may be used instead.

〔Effect of the invention〕

As described above, according to the present invention, the phase and intensity of higher-order modes other than the fundamental wave mode in the resonator are detected, and according to the results, the phase and intensity of higher-order modes other than the fundamental wave mode are opposite in phase and have the same intensity. Since the structure is configured to excite higher-order modes within the resonator, modes other than the fundamental wave mode can be actively controlled, resulting in a device that can sufficiently stabilize the particle beam without affecting the fundamental wave mode. It has the effect of

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a beam stabilizing device according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional stabilizing device. 7 is a T M IIo anti-phase mode excitation antenna, and 12 is T M r +. A mode oscillator, 13 an attenuator, 14 a phase shifter, and 15 a terminating resistor. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (3)

[Claims] (1) In the high-frequency cavity of a ring particle accelerator, the phase of higher-order modes other than the fundamental mode is determined from the electromagnetic field within the cavity.
It is characterized by comprising: a detection means for detecting the intensity; and an excitation means for exciting a higher-order mode having an opposite phase and the same intensity as a higher-order mode other than the fundamental mode into the cavity according to the detection result of the detection section. High frequency cavity. (2) The detection means includes a search coil provided in the cavity, a filter that cuts a fundamental mode from the detection output of the search coil, and a phase and intensity of a higher-order mode obtained from the filter. The high-frequency cavity according to claim 1, characterized in that it comprises a phase detector and an intensity detector for detecting. (3) The excitation means includes an oscillator that oscillates a high-order mode, a phase shifter that gives a phase opposite to the phase detected by the phase detector to the high-order mode from the oscillator, and a phase shifter that provides a phase opposite to the phase detected by the phase detector to the high-order mode from the oscillator; an attenuator that makes the intensity of the mode the same as the intensity detected by the intensity detector; an infinite terminating resistor for a fundamental mode connected between the attenuator and the high frequency cavity; and an excitation antenna connected to the terminating resistor.
High frequency cavity as described in section.