JPH0266899A - High frequency power supply device - Google Patents

Abstract

PURPOSE:To provide unmanned operation of continuous discharge caking by furnishing a control means, judging the discharge situation from the degree of vacuum, and shutting off the high frequency power supply in case any abnormality has arisen. CONSTITUTION:The incident electric power irradiated to the cavity body 1 constituting a vacuum vessel is measured by a directional coupler 9a and a power meter 10a, and the reflected ligft beam is measured by another directional coupler 9b and power meter 10b, The degree of vacuum in the body 1 is measured by a vacuum meter 12, and all measured values are fed into a control device 13. The control device 13 senses the degree of vacuum, judges the discharge situation in the body 1, and controls a high frequency power supply 5. Further the device 13 senses the incident power and reflex power, and in case an abnormal discharge such as perfect shortcircuiting is judged on the basis of sensed value, the high frequency power supply 5 for supply to the vacuum vessel is shut off. This enables unmanned operation of discharge caking of a high frequency apparatus concerned.

Description

Detailed Description of the Invention [Purpose of the Invention (Industrial Field of Application) The present invention relates to a high-frequency power source that supplies high-frequency power into a vacuum container in order to, for example, accelerate processing of a particle beam inside an ultra-high vacuum container. Regarding equipment.

(Conventional technology) Various high-frequency devices are used in accelerators and nuclear fusion devices.
Many of them are kept in ultra-high vacuum conditions.

For example, a high-frequency acceleration cavity accelerates particle beams such as electrons, protons, and ions orbiting in an accelerator using high-frequency waves synchronized with the particle beams, and is an important device at the heart of the accelerator.

This high-frequency acceleration cavity includes a cavity body, an antenna for supplying high-frequency power into the cavity body, a tuner for finely adjusting the resonant frequency within the cavity body, and a It consists of a vacuum exhaust system to maintain a high vacuum.

Inside the cavity body, together with the beam duct through which the particle beam circulates, it is necessary to maintain an ultra-high degree of vacuum of approximately 10 = TOrr or more. The reason for this is to reduce residual gas molecules and prevent scattering of the particle beam due to collisions with accelerating particles, thereby preserving the lifetime of the particle beam, and to prevent discharge due to the high electric field that is unavoidable in accelerators.

In addition, the voltage applied to the accelerating electrode inside the cavity body during particle beam acceleration requires a maximum of several tens to hundreds of kilovolts. Even in a small accelerator, the high-frequency power supplied to the particle beam reaches tens of kilowatts during particle beam operation.

Here, regarding the conventionally used high frequency power supply equipment,
This will be explained with reference to the schematic configuration diagram shown in FIG. 1 in the figure is a high frequency acceleration cavity main body (hereinafter referred to as the cavity main body),
This has an evacuation port 2, and a vacuum evacuation system is constructed by sequentially passing a vacuum valve 3 and a vacuum pump 4 to this evacuation port 2, and the vacuum pump 4 always maintains a high vacuum inside the cavity body 1. It is maintained. This vacuum state is detected by a vacuum gauge 12, and a pressure signal detected by the vacuum gauge 11 is input to this vacuum gauge 12. Then, high-frequency incident power from a high-frequency power source 5 is supplied into the cavity main body via a circulator 6 and an antenna 7. The reflected power from the cavity body 1 is then consumed by the dummy load 8 via the antenna 7 and the circulator 6. In this case, the incident power is measured by the directional coupler 9a and the power meter 10a, and the reflected power is measured by the directional coupler 9b and the power meter 10b.

In the conventional high-frequency power supply H having such a configuration, it is actually impossible to suddenly supply high-frequency power reaching tens of kilowatts into the cavity body 1 as described above.

The reason for this is that a phenomenon called electric field emission or multipactoring discharge occurs.

This electric field radiation is caused by the fact that no matter how high the vacuum is maintained inside the cavity body 1, if there is an input power of about 100 W, the electric field will concentrate on the very minute protrusions existing on the inner surface of the cavity body 1, and the electrons will be emptied. This is a phenomenon in which radiation is emitted from the surface of the trunk body 1. In addition, multipactoring discharge is a phenomenon in which secondary electrons newly emitted when electrons hit the electrode surface are accelerated by a high-frequency electric field, and can occur even at voltages that are extremely lower than the normal discharge breakdown voltage. , due to multipactoring discharge,
The incident power that enters the cavity body 1 is limited to a small value.

In order to prevent these phenomena, it is necessary to dry up the discharge inside the cavity body 1 before operation. This discharge decay is achieved by continuously causing weak discharges while gradually increasing the incident power, creating a surface condition that makes it difficult for electric field radiation and multi-pattering discharge to occur, and finally in the process of injecting the specified high power. be.

When performing discharge depletion, if the scale of the discharge increases, the tip of the antenna 7 will become short-circuited, and the incident power will be totally reflected by the antenna 7, and no further power will be incident on the antenna 7. You must be careful as this may damage various parts. In reality, when performing discharge depletion, it is impossible to avoid short-circuit reflections, so we try to avoid placing an excessive load on the antenna 7. Therefore, when all the incident power on the antenna 7 is reflected, It is necessary to immediately reduce the output from the high frequency power supply 5. Normally, when the outputs of the wattmeters 10a and 10b become approximately equal, the output of the high-frequency power source 5 is quickly manually reduced.

On the other hand, when a multi-vacuum discharge occurs, the degree of vacuum inside the high-frequency acceleration cavity 1 decreases, and becomes about 10<-6 >Torr after short-circuit reflection due to a large discharge. Therefore, in order to inject power again, the degree of vacuum must rise again and at least 10
= You have to wait until it reaches about TOrr.

As described above, in the conventional high-frequency power supply device, the high-frequency power from the high-frequency power supply 5 is input from the antenna 7 into the cavity main body 1 which is always maintained in a vacuum by the vacuum pump 4. Then, the incident power is gradually increased, and when the antenna 7 is short-circuited and the incident power is totally reflected, the power input from the high frequency power source 5 is immediately stopped. Thereafter, after confirming with the vacuum gauge 12 that the degree of vacuum has increased, the operation of gradually inputting power is repeated again until the specified power is finally reached.

(Problem to be Solved by the Invention) In order to increase the incident power to the specified power value due to the discharge decay described above, a high frequency power supply is required to operate continuously for several days to several weeks. High frequency power supply equipment
Since no consideration was given to equivalent discharge decay,
It is unsuitable for long-term continuous discharge aging.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a high-frequency power supply device that can perform continuous discharge aging over a long period of time in an unmanned operation, and can achieve significant labor savings.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention supplies high frequency power from a high frequency power supply to an antenna installed in a vacuum container of a high frequency device, In the apparatus for processing a particle beam in the vacuum container, the apparatus includes a first means for detecting the degree of vacuum in the vacuum container to determine a discharge state of the antenna and controlling the high frequency power source; The incident power entering the container and the reflected power reflected from the vacuum container to the antenna are detected, and when an abnormal discharge such as a complete short circuit is determined based on the detected values, the high-frequency power source enters the vacuum container. and second means for cutting off power supplied to the.

(Function) According to the high frequency power supply device according to the present invention, the discharge status is determined based on the degree of vacuum and the output of the high frequency power supply is controlled, and the incident power and reflected power to the high frequency equipment are monitored to prevent abnormalities such as complete short circuits. If this occurs, the high-frequency power supply is immediately shut off, making it possible to automatically dry up the discharge of the high-frequency equipment.

(Example) Hereinafter, an example of the present invention will be described with reference to FIG. Here, the high-frequency acceleration side will be explained as the high-frequency device, but the present invention is not limited to this and any other device may be used. The incident power that enters the cavity body 1 constituting the vacuum container is transmitted through the directional coupler 9.
a and a wattmeter 10a, and this measured value is input to a control device 13, which will be described later. Further, the reflected power from the cavity body 1 is guided to the dummy rod 8 via the circulator 6, where the power is consumed, but the reflected power is measured by the directional coupler 9b and the wattmeter 10b, and this measurement The values are also input to the control device 13. Power meters 10a, 10b
The incident power and the reflected power measured at The output of the high-frequency power source 5 is controlled based on this judgment, and the control device 13 closes the vacuum valve 3 in the event of an emergency where the vacuum inside the cavity body 1 is destroyed. controlled as follows.

Regarding the basic operation of discharge depletion, the control device 13 has the first function described later. Second. The third setting values can be set respectively. That is, the first setting value is the cavity body]
A value indicating that the influence of a decrease in the degree of vacuum inside the chamber can be ignored is set to, for example, 10-8 TOrr. Further, the second set value is a value indicating the progress of discharge with a small degree of vacuum in the cavity main body 1, for example, 10=TOrr. Further, the third set value is a value indicating deterioration of the degree of vacuum inside the cavity body 1, for example, 10-'
Let it be Torr.

When the relationship between these set values is as follows, the control device 13 specifically controls as follows. First, when increasing the incident power gradually, high frequency type 1
The output of the iX5 is controlled to increase based on a pre-specified output increase rate, and when the degree of vacuum falls below a second set value due to discharge, the high frequency power source 5 is controlled to the same level. Instead, it waits for the degree of vacuum to rise with the output of the high frequency power source 5, and when the first set value is reached, the output of the high frequency power source 5 is controlled to be increased again. Furthermore, if a discharge that causes total reflection occurs within the cavity main body 1, it is determined that the incident power or reflected power values at the wattmeter 10a10b become equal. In this case, the control device 13 performs control to immediately stop the high-frequency power source 5 regardless of the degree of vacuum, and restarts the high-frequency power source 5 after stopping its output by setting the first set value in the vacuum gauge 12. This is done after it has been confirmed that the degree of vacuum has been achieved.

In addition, when the degree of vacuum within the cavity body 1, that is, the value detected by the vacuum gauge 12, becomes a degree of vacuum below a third set value, the control device 13 performs control to immediately close the vacuum valve 3, Maintenance of the vacuum gauge 12 is performed with the vacuum valve 11 closed, and the high frequency power source 5 is simultaneously shut off.

From the above, in the conventional high-frequency power supply device, the work of drying out the cavity body 1 and applying the high-frequency power according to the specifications required a manned person for a long period of time, but with the embodiment of the present invention, For example, since the high frequency power source 5 and the vacuum valve 3 are controlled by the control device 13, continuous operation without an operator is possible, and significant labor savings are possible. The discharge drying mentioned above is −
This is not a one-time operation, and if the cavity main body 1 is opened to the atmosphere, it is necessary to perform it again, so automation is very effective in this sense as well.

[Effects of the Invention] According to the present invention described above, it is possible to provide a high-frequency power supply device that can perform continuous discharge aging over a long period of time in an unmanned operation, and can achieve significant labor savings.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of a high frequency power supply device according to the present invention, and FIG. 2 is a schematic diagram showing an example of a conventional high frequency power supply device. 1... High frequency acceleration cavity body, 2... Vacuum exhaust port, 3... Vacuum valve, 4... Vacuum pump, 5... High frequency power supply, 6... Circulator, 7... Antenna ,
8... Dummy load, 9a, 9b... Directional coupler, 10a, ], Ob... Power meter, 11... Vacuum gauge, ]2 12... Vacuum gauge, 13... Control Device.

Claims (1)

[Scope of Claim] A device for supplying high frequency power from a high frequency power supply to an antenna installed in a vacuum container of a high frequency device and processing a particle beam in the vacuum container, comprising: a vacuum in the vacuum container; a first means for controlling the high-frequency power source by detecting the discharge state of the antenna by detecting the electric discharge state of the antenna; a second means for detecting electric power and, when abnormal discharge such as a complete short circuit is determined based on the detected value, cutting off electric power supplied from the high frequency power source to the inside of the vacuum container; Device.