JPH04149999A - High frequency acceleration device for accelerator - Google Patents

Abstract

PURPOSE:To make a linac for initial acceleration compact by installing two or more cavities in a cyclic passage of a particle cyclic accelerator, and deflecting the phase differences of high frequency voltages of the cavities from each other based on a reference. CONSTITUTION:In the case of installation of two cavities 5, acceleration particles are accelerated based on a composite value of high frequency voltages generated at the respective cavities 5. The phase difference of the high frequency voltages generated at the cavities 5 is changed between 180 deg. and 0 deg. to set a dynamic range infinitive. By controlling the phase difference between the two cavity voltages based on a predetermined phase reference, the control range of the cavity voltage can be wide. A linac for initial acceleration can thus be compact.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Field of Application) The present invention relates to a high-frequency accelerator device for an accelerator that allows a wide control range of particle acceleration voltage.

(Prior Art) Particle acceleration systems using synchrotron accelerators as shown in FIGS. 3 and 4 are conventionally known.

To explain this, first, in FIG. 3, 1 is a synchrotron accelerator, which is equipped with a linac 2 for initial acceleration, an injector 3, and a plurality of bending electromagnets 4.4, . Particles are incident on an injector 3 from a linac 2 and are passed through a plurality of bending electromagnets 4, 4 . ... is configured to be passed through the magnetic field of... and returned to the injector 3 again by being deflected,
Particles are designed to circulate along this path. A cavity 5 is provided in the path along which the particles circulate, and each time the particles pass through this cavity 5 during their circulation, they are accelerated by a high frequency voltage generated inside the cavity. 6 is a vacuum beam duct formed along the path of the particles.

In FIG. 4, a power input device 7, a tuner 8, and a probe 9 are provided in the cavity 5, and by supplying high frequency power into the cavity 5 by the power input device 7, particles are generated in relation to the tuner 8. A high frequency voltage for acceleration is generated, and by moving the tuner 8, the resonant frequency within the cavity 5 is adjusted. The probe 9 is used to obtain a high frequency signal having a voltage value corresponding to the strength of the high frequency voltage inside the cavity 5, and this high frequency signal is used to control the amplitude of the high frequency power applied to the cavity.

10 is an original oscillator, 11 is an attenuator, 12 is a power amplifier, 13 is a dummy load, 14 is a circulator, 15
is a tuner control device, 16 is an attenuator control device, 1
7 is a cavity voltage detector.

The amplitude of the high frequency signal from the original oscillator 10 is controlled by an attenuator 11, and the controlled high frequency signal is amplified by a power amplifier 12, and then supplied to the cavity 5 as high frequency power by a power input device 7 via a circulator 14. Ru. Further, the reflected high frequency power from the power input device 7 is transmitted to the dummy load 13 side and absorbed therein.

The tuner 8 is adapted to be moved to a tuning position by a tuner control device 115.

The high frequency signal from the probe 9 is input to the cavity voltage detector 17, and this cavity voltage detector 17 generates a DC voltage signal with a voltage value corresponding to the amplitude of the high frequency signal Vc (rf), which is used for cavity voltage detection. Output as a signal.

The attenuator controller 16 has a reference voltage signal Vc (ref
) and the cavity voltage detection signal VC are input, the attenuator controller 16 compares the voltage values of the two and outputs an attenuator control signal representing a target value taking into account the difference. This attenuation control signal is input to an attenuator 11, which outputs a high frequency power signal having a power value corresponding to the power value represented by the attenuator control signal, and this high frequency power signal is outputted through a power amplifier 12.

(Problems to be Solved by the Invention) In a high-frequency accelerator such as the conventional example, the controllable range (hereinafter referred to as dynamic range) of the cavity voltage Vc is limited to the range of the attenuator 11 and the power amplifier 12 (e.g., tetrode, klystron). Determined by characteristics, approximately 20d
It becomes B. Therefore, the pattern of the cavity voltage Vc for particle acceleration is as shown in FIG. 5(a), and V c Wax and V
The difference in c■in can only be about 20 dB. In such a case, the initial acceleration linac must be used to increase the energy at the time of incidence into the synchrotron accelerator. The higher the final acceleration energy of the particles (for example, several 10011 or more in terms of electric power), the greater the acceleration energy borne by the initial acceleration linac. Such an accelerator has the problem that the linac for initial acceleration also becomes large, and the accelerator system itself becomes large.

The object of the present invention is to achieve a dynamic range of 3
It is an object of the present invention to provide a high frequency accelerator device for an accelerator which can obtain 0 dB or more and thereby make a linac for initial acceleration compact.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides an accelerator for accelerating particles in which particles can circulate, in which two or more This device is characterized by comprising a cavity, a phase detector that detects the phase between each cavity, and a phase shifter that can control the phase between each cavity according to a phase reference.

(Function) According to the present invention, by utilizing the fact that the composite value of the high frequency voltages generated in each cavity can be equivalently regarded as the cavity voltage felt by the accelerated particle, the high frequency voltages of each cavity are shifted based on the phase difference between the two cavities. As a result, the dynamic range of the cavity voltage Vc can be increased to 30 dB or more. Therefore, the initial acceleration linac can be downsized.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2. Elements having the same functions as those in the conventional example shown in FIGS. 3 and 4 are given the same reference numerals, and their explanations will be omitted.

In the configuration of the accelerator shown in FIG. 1, compared to the conventional example shown in FIG. 3, the number of cavities 5 is increased by one, resulting in two cavities. In the high-frequency accelerator shown in Figure 2, compared to the conventional example shown in Figure 4,
It has a control system for two cavities 5. 18 is a phase shifter, 19 is a phase controller, 20 is a phase detector, and 21 is a directional coupler.

The operation of the present invention will be explained below with reference to FIGS. 1 and 2. When two cavities 5 are provided as shown in FIG. 1, the high frequency voltage felt by the accelerated particles due to each cavity 5 is Vc 1sin (2πf −t
θ1 ) −・・■Vc 2sin (2πf
It is expressed as −t+θ2 > −···■.

However, Vcl and Vc2 are the amplitudes of the voltages in the respective cavities 5, f is the frequency, and θ1. θ2 represents the phase shift of each cavity.

The accelerated particles are accelerated by the combined value of the high frequency voltages generated in each cavity 5.

The composite value of formulas ① and ② is Vc 1sin C2x f- as Vcl-Vc2-Vc
2sin (2, v f-t + θ 2) θ
1-θ2-2Vccos(), 8i. (2,, f, t+01-02 > ,,,■
It is expressed as θ1−θ2 is a phase difference Δψ between high frequency voltages generated in each cavity.

In formula (2), when there is only one cavity, the dynamic range of the cavity voltage Vc is determined only by the Vc value. When there are two cavities, cos[(θ1
-θ2)/2] can also control the dynamic range of Vc.

In other words, if the phase difference Δψ is changed from 180 @ to O'', the term COS[(θ1-θ2)/2 can be reduced to O''.
It can be changed from 1 to 1, making the dynamic range infinite.

In reality, for example, if you want to have a dynamic range of 40 dB, you will have a dynamic range of 20 dB with Vc, and then change cost (θ1-θ2)/2] by 0.
01-θ2 from about 170° to 06 so that it becomes 1 to 1
change to

In this way, when driving with the acceleration pattern of the cavity voltage Vc as shown in Fig. 5(a) and the pattern of the phase difference Δψ as shown in Fig. 5(b), the accelerated particles will equivalently feel The cavity voltage that can be controlled can be set to a dynamic range of 40 dB as shown in FIG. 5(c).

FIG. 2 shows the configuration of a high frequency accelerator for realizing the above-described control. What is different from the conventional example is that there are now two cavities and one phase shifter for phase control.
8, phase controller 19, phase detector 20, directional coupler 2
1 has been added.

The phase difference Δψ between the two cavity voltages is determined by inputting the high frequency signal from the directional coupler 21 to the phase detector 20,
generated. The phase difference signal Δψ output from the phase detector 20 is input to the phase controller 19 and represents a target value such that the phase difference Δψ becomes the phase difference reference Δψ (ref). Outputs phase shifter control signal. This phase shifter control signal is input to the phase shifter 18, so that the phase difference between the cavity voltages of the two cavities 5, 5 operates in a pattern as shown in FIG. 5(b), for example.

According to the embodiment of the present invention, the control range of the cavity voltage Vc can be equivalently widened to 30 dB or more.

[Effects of the Invention] As explained above, according to the present invention, the control range of the cavity voltage Vc can be equivalently widened to 30 dB or more, and as a result, the initial acceleration linac can also be downsized. It is possible to provide a high-frequency accelerator device that can be used as an accelerator.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of a synchrotron accelerator to which the present invention is applied, Fig. 2 is a block diagram showing an embodiment of the high frequency accelerator of the accelerator of the present invention, and Fig. 3 is a conventional synchrotron accelerator. FIG. 4 is a block diagram showing an example of a conventional high-frequency accelerator device, and FIG. 5 is a diagram showing pattern operation of cavity voltage Vc and phase difference Δψ. 1... Synchrotron accelerator, 2... Linac,
3... Injector, 4... Bending electromagnet, 5... Cavity, 6... Vacuum beam duct, 7... Power input device, 8... Tuner 9... Probe, 10...・
Original oscillator, 11... Attenuator, 12... Power amplifier, 13... Dummy load, 14... Circulator, 15... Tuner control device, 16... Attenuator controller, 1.7...・Cavity voltage detector,
18... Phase shifter, 19... Phase controller, 20...
Phase detector, 21... directional coupler, Vc (re
f)...Cavity voltage reference, Δψ(ref)・-
・Phase difference reference, Vc...cavity voltage, Δψ...
Phase difference between two cavities 5,5. Applicant's agent Patent attorney Takehiko Suzue Figure Figure Time (a) (b) Figure

Claims (1)

[Claims] An accelerator for acceleration in which particles can circulate, comprising two or more cavities disposed in a path along which the particles circulate, a phase detector that detects the phase between each cavity, and a phase detector that detects the phase between each cavity. 1. A high-frequency accelerator for an accelerator, comprising a phase shifter that can control the phase of the accelerator according to a phase reference.