JP2628185B2 - Acceleration power supply for ion source - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration power supply for an ion source, and more particularly to an acceleration power supply for an ion source used in a nuclear fusion device or an ion implantation device. Regarding acceleration power supply.

[Conventional technology]

2. Description of the Related Art As a conventional acceleration power supply for an ion source, those shown in FIGS. 2 to 4 are known. Rectifier 30 Each power supply that converts AC power from a commercial power supply into DC power of 100 kV, a capacitor C for smoothing the output of the rectifier 30, have a vacuum tube 34 for supplying the output of the rectifier 30 to the accelerating electrode via the end T ₁ A resistor 31 and a crowbar switch 32 are connected in series to both ends of the rectifier 30, and a grounding device 33 is connected. Dividing resistors 35,36-1 ...... 36-n between the power supply shown in FIG. 2 and the terminal T ₁ and the terminal T _3, the voltage dividing resistors changer 37-1 ...... 37-
n are provided, so a voltage divided by the voltage dividing resistors and the voltage dividing resistors 35 that are selected by the voltage dividing resistors changer via the terminal T ₂ to be applied to other acceleration electrodes I have.

In case of power shown in FIG. 3, the voltage dividing resistors 35A between the terminals T ₁ and the terminal T _3, 35B and the vacuum tube 34A, 34B is inserted, the vacuum tube 34A, a voltage controlled by 34B via the terminal T ₂ is adapted to be applied to other acceleration electrode. In the case of acceleration power supply shown in Fig. 4, the terminal T ₁ and the terminal
Dividing resistors 35-1 ...... 35-n between T _3, are inserted 35C and the semiconductor switch 38-1 ...... 38-n, the voltage by the control of the semiconductor switches 38-1 to 38-n via the terminal T ₂ is adapted to be applied to other acceleration electrode.

In each of the power supplies, a high voltage is applied to each acceleration electrode of the ion source, ions generated from the ion source are extracted from the ion source, and ions are accelerated by each acceleration electrode to obtain a high-speed ion beam. ing. When the ion source is operated by each power supply, a short circuit frequently occurs between the electrodes because a high voltage is applied between the electrodes. Therefore, in order to prevent the electrodes from being destroyed by the short-circuit between the electrodes, when a short-circuit between the electrodes occurred, the vacuum tube 34 was controlled to separate the accelerating power supply from each of the accelerating electrodes, and the short-circuit between the electrodes was recovered. Later, the vacuum tube 34 is controlled again to quickly apply the DC power from the acceleration power source to each acceleration electrode. Further, since it is necessary to apply a constant voltage to each accelerating electrode, the vacuum tube 34 is required to have a high voltage constant control, a high-speed cutoff, and a high-speed reconnection function. When a short circuit occurs between the electrodes, the crowbar switch 32
Is turned on and the output of the rectifier 30 is short-circuited by the resistor 31 and the crowbar switch 32. During the suspension of operation, the grounding device 33 is turned on to discharge the electric charge stored in the capacitor C.

[Problems to be solved by the invention]

In the above prior art, in order to apply a voltage to a plurality of accelerating electrodes, a method of dividing a main output voltage which is an output of the vacuum tube 34 is adopted. As a method of dividing the main output voltage, FIGS. Although the power supplies shown in FIG. 4 are employed, each power supply has the following disadvantages.

(1) Voltage division method by resistance (I) Since a current flows through the resistance, the power consumption of the voltage division resistance becomes extremely large, and the device becomes large.

(II) Since most of the current flowing through the voltage dividing resistor is lost, the capacity of the main circuit is increased.

(III) A large-capacity, high-purity (high-resistance) pure water cooling device is required to cool the resistance.

(IV) The output voltage ratio of each stage cannot be controlled during operation.

(2) Voltage division method using vacuum tube (I) It is necessary to control a large-capacity vacuum tube while a high voltage is applied.

(II) A pure water cooling device for cooling the vacuum tube is required.

(3) Voltage division method using semiconductor element and resistor (I) There is a problem similar to that shown in (I) to (III) in the voltage division method using a resistor.

The drawbacks of each partial pressure method are summarized as follows.

(I) The loss at the voltage divider is large.

(II) Ancillary equipment such as a large-capacity high-purity pure water cooling system is required.

(III) The device becomes larger.

As described above, the conventional voltage dividing method has the above-described disadvantages, and thus it is difficult to increase the output voltage of the acceleration power supply to 500 kV to 1 MV.

Further, in each of the conventional methods, since the voltage dividing capacitor C is inserted in the output of the rectifier 30, the vacuum tube 34 is immediately turned off when the electrodes are short-circuited, thereby preventing the charge of the capacitor C from flowing into the ion source. However, the control system for controlling the vacuum tube 34 may malfunction due to the surge voltage of the capacitor C. In addition, since a high voltage is applied to the vacuum tube 34, a high-voltage control signal must be applied to the vacuum tube 34 in order to control the vacuum tube 34, and a device for controlling the vacuum tube 34 must have a higher voltage. Must. That is, in order to control the vacuum tube 34, it is necessary to control with a potential floating at a high voltage.

An object of the present invention is to provide an acceleration power supply for an ion source that can control a voltage to be applied to an acceleration electrode with a voltage lower than a voltage applied to the acceleration electrode.

[Means for solving the problem]

To achieve the above object, the present invention provides a converter for converting AC power to DC power, a high-frequency inverter for converting DC power of the converter output to AC power having a higher frequency than the frequency of the AC power of the converter, It has a multi-stage high-voltage DC power supply including a high-frequency transformer that boosts the output voltage of the inverter and a high-frequency converter that converts the AC power output from the high-frequency transformer into high-voltage DC power. The high-voltage DC power supply of each stage is connected in series, and the output of the high-voltage DC power supply of each stage is connected to each acceleration electrode of the ion source. This constitutes an ion source acceleration power supply connected. Still further, an acceleration power supply for an ion source is provided in which at least a transformer having a large voltage difference between an input voltage and an output voltage among the high-frequency transformers at each stage is constituted by an insulating transformer.

[Action]

A voltage from a high-voltage DC power supply of each stage is applied to each accelerating electrode. The power supply of each stage can adjust the output voltage by controlling the converter and the high-frequency inverter. That is, the output voltage of each stage can be controlled by the low voltage. Further, since high-frequency AC power is converted into DC power by the high-frequency converter, a smoothed DC voltage can be applied to each accelerating electrode without connecting a smoothing capacitor to the output of each power supply.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIG.

In FIG. 1, a main DC power supply 1 and slave DC power supplies 2A and 2B are respectively a converter 10, 20A, 20B, a high-frequency inverter 11,
21A, 21B, high-frequency transformers 12, 22A, 22B, high-frequency inverter 1
3,23A, 23B, converters 10,20A, 20B
Are connected to the commercial power supply, respectively,
3A and 23B are respectively connected in series and connected to the acceleration electrode of the ion source. That is, in order to draw the negative ions from the ion source of a high output voltage, the positive terminal of the high-frequency converter 13 is grounded via a terminal T _4, - terminal via the terminal T ₁ is connected to the accelerating electrode of the high voltage I have. High frequency converter 23
A is - terminal grounded to the terminal T _1, + terminal is connected to the accelerating electrode of the second stage via a terminal T _2. Frequency converter 23B is - terminal is connected to the positive terminal of the high-frequency converter 23A, + terminal is connected to the acceleration electrode of the third stage via a terminal T _3.

Converters 10, 20A, and 20B convert AC power from commercial power into DC power, and supply the converted output power to high-frequency inverters 11, 21A, and 21B. The high-frequency inverters 11, 21A, and 21B convert the input DC power into AC power having a frequency higher than the frequency of the commercial power supply, and supply the converted output power to the high-frequency transformers 12, 22A, and 23B. The high-frequency transformers 12, 22A, and 22B boost the AC voltage input to the primary side from the secondary side to a high-voltage AC voltage, and supply the boosted AC voltage to the high-frequency converters 13, 23A, and 23B. ing. The high frequency converters 13, 23A and 23B are configured to convert the input AC voltage into a high DC voltage. For example, as the first stage acceleration electrode of the ion source, 50
When a voltage of 0 kV is required, the high-frequency converter 13
Output a voltage of 500 kV. Each of the high-frequency converters 23A and 23B has an output capacity corresponding to the input capacity of each acceleration electrode. That is, a voltage to be applied to each acceleration electrode is supplied by controlling the high-frequency converters 23A and 23B.

The DC voltage output from each stage's DC power supply is
Arbitrary values can be obtained by adjusting the control signals of the 10, 20A, 20B and the high-frequency inverters 11, 21A, 21B. That is, the output of the DC power supply at each stage can be controlled by a control signal having a voltage lower than the voltage to be applied to each acceleration electrode. Therefore, even when controlling the converters 10, 20A, 20B and the high-frequency inverters 11, 13, 21A, 21B, 23A, 23B, it is not necessary to increase the voltage of each control signal, and the output voltage can be easily adjusted. Becomes possible. Further high-frequency inverters 11,2
The frequency of the output signals of 1A and 21B is changed to a signal of, for example, a frequency of 10 kHz. Can be output. Therefore, it is possible to prevent the control system from malfunctioning due to the charge voltage of the smoothing capacitor. Further, since high-frequency AC power is converted to DC power, even without inserting a vacuum tube on the output side of the high-frequency converter 13,
When the electrodes are short-circuited, the DC power supply of each stage can be quickly turned on and off.

In addition, the high-frequency transformer 22 of the high-frequency transformers 12, 22A and 23B
If A and 22B are constituted by insulating transformers, the transformers 22A and 22B will not cause dielectric breakdown even if the voltage difference between the primary side and the secondary side is large.

In the present embodiment, since the DC power supply of each stage may be configured with an output capacity corresponding to the input capacity of each acceleration electrode, it is possible to greatly reduce the capacity of the entire power supply as compared with the conventional one. Become. Furthermore, since each converter and inverter can be controlled with reference to the ground potential, control when the electrodes are short-circuited and control for adjusting the output voltage are facilitated. Furthermore, since ancillary equipment such as high-purity pure water cooling equipment is not required, the entire apparatus can be downsized.

〔The invention's effect〕

As described above, according to the present invention, a DC power supply is provided for each of a plurality of acceleration electrodes, and each DC power supply is controlled at a voltage lower than a voltage to be applied to the acceleration electrodes. Loss can be greatly reduced, which can contribute to a reduction in power supply capacity, and can eliminate the need for ancillary equipment, thereby contributing to a reduction in the size of the device. Further, by constituting the high-frequency transformer with an insulating transformer, it is possible to prevent the high-frequency transformer from being broken down even when the frequency is increased.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIGS.
The figures are each a configuration diagram of a conventional example. 1… Main DC power supply, 2A, 2B… Subordinate DC power supply, 10,20A, 20B… Converter, 11,21A, 21B… High frequency inverter, 12,22A, 22B
… High frequency transformer, 13,23A, 23B… High frequency converter.

Claims (2)

(57) [Claims] 1. A converter for converting AC power into DC power, a high-frequency inverter for converting DC power output from the converter into AC power having a frequency higher than the frequency of the AC power of the converter, and boosting an output voltage of the high-frequency inverter. It has a high-frequency transformer and a plurality of stages of high-voltage DC power supplies including a high-frequency converter for converting AC power output from the high-frequency transformer into high-voltage DC power. For an ion source consisting of an output capacity corresponding to the capacity, the high-voltage DC power supplies of each stage are connected in series, and the output of the high-voltage DC power supply of each stage is connected to each accelerating electrode of the ion source. Acceleration power supply. 2. The acceleration power supply for an ion source according to claim 1, wherein at least one of the high-frequency transformers of each stage having a large voltage difference between the input voltage and the output voltage is constituted by an insulating transformer.