JP3101426B2 - Ion accelerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion accelerator.

[0002]

2. Description of the Related Art FIG.
1 shows a V ion accelerator, in which a high voltage terminal 2 is provided in a shield box 1, which contains an ion source 3, a mass separation magnet (not shown), and an extraction electrode (not shown). In addition, a predetermined high voltage is applied from a high voltage generator 5 which is arranged on the side and is schematically shown. The high-voltage terminal 2 is supported on a floor 10 by an insulating post 6, and its lower end is fixed to a bracket 7, and its height is increased by stud bolts 9 planted on a support plate 8 fixed to the floor 10. It is arranged to be adjustable. In the high-voltage terminal 2, the above-mentioned ion source 3 is supported on the bottom wall of the high-voltage terminal 2 by a support 13 made of an insulating material. 4 is attached.

The operation of the conventional example is as described above. The operation will be described below. After ions are extracted from the plasma generated by the ion source 3 by an extraction electrode (not shown), a mass separation magnet (not shown) is also formed. By
Only predetermined ions are incident on the acceleration tube 4. The valence of ions from the high voltage terminal 2 to which a voltage of 400 KV or more is applied by the high voltage generator 5 to the ground potential,
The energy of the product of this voltage is given and accelerated through the acceleration tube 4.

In order to electrically insulate the high voltage terminal 2 from the ground potential of the floor 10, an insulating post 6 is installed between the floor 10 and the high voltage terminal 2. The height of the insulating post 6 is formed to be long in accordance with the voltage to be insulated. In the present conventional example, each element is made of epoxy resin, but is divided into four parts. 6. The insulating column 6 is fixed to the bottom wall of the high-voltage terminal 2 with screws 14.

In the ion accelerator of FIG. 3, since the material of the insulating pillar 6 is an organic substance, the high voltage terminal 2 and the floor 10
If a discharge occurs along the column between the above and the ground potential, carbonization occurs, or if a leakage current flows along the surface of the insulating column 6, the material deteriorates due to aging. Further, by accelerating the ion beam, X-rays are generated in the accelerating tube 4,
If this hits the insulating pillar 6, this material is chemically changed, which causes deterioration of the material. Furthermore, the ion accelerator of FIG. 3 uses an insulating column having a withstand voltage of 400 KV or more. However, such an insulating column is not generally commercially available, and is manufactured exclusively for this high-voltage ion accelerator. The price is very high, and with the same performance (withstand voltage and withstand load), the price is 6 to 7 times higher than that of the insulating pillar made of an insulator described below with reference to FIG.

FIG. 4 shows an ion accelerator of another conventional example. The parts corresponding to those of the above-mentioned conventional example are denoted by the same reference numerals, and the detailed description thereof will be omitted.

That is, in this conventional example, an insulating support column 12 made of ceramic, that is, an insulator is used. Attachment fittings 15 and 16 are fixed to the upper end and the lower end with adhesives. It is screwed to the bottom wall of the high voltage terminal 2. The lower mounting bracket 16 is fixed to the bracket 7 with screws 18. This is fixed to the support plate 8 via stud bolts 9. Since screw holes cannot be formed in the insulating support column 12 made of an insulator, the mounting brackets 15 and 16 are fixed with an adhesive as described above, and the bottom wall portion of the high-voltage terminal 2 and the bracket 7 are interposed therebetween.
It is fixed to.

Although this conventional example performs the same operation as the above-mentioned conventional example, it has the following disadvantages. That is, as shown in FIG.
A high voltage of KV is applied, and an upper mounting bracket 15 is fixed to this by a screw 14.
Since this protrudes downward from the bottom wall surface of the high-voltage terminal 2, the equipotential level L has a shape protruding downward as shown in FIG. 5, which distorts the electric field in these portions, and Discharge and the like are easily induced.
The same can be said for the lower mounting bracket 16, and the equipotential surface also has a distorted shape protruding upward on the floor 10 side, and there is a possibility that corona or electric discharge may also occur at this portion.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a low-cost ion accelerator which does not distort the equipotential level at its upper and lower ends. And

[0010]

The object of the present invention is to provide a casing having at least a built-in ion source and a mass separating magnet supported on a floor at a predetermined height by ceramic insulating columns, In the ion accelerator, a predetermined high voltage is applied to the casing to supply power to the ion source, the mass separation magnet, and the like by a power supply device. In the ion accelerator, an opening is formed in a bottom wall portion of the casing; The mounting bracket projects from the opening into the casing such that the bottom surface of the upper mounting bracket fixed to the upper end of the upper part is at least above the bottom surface of the casing, and the lower part fixed to the lower end of the insulating support post The upper surface of the mounting bracket is positioned below the opening formed in the plate so that it is at least below the upper surface of the ground potential plate that is stretched above the floor. The insulating pillar is disposed so as to protrude to the upper side, and the upper mounting bracket and the lower mounting bracket are respectively fixed to a mounting plate and a floor disposed in the casing. Is achieved by an ion accelerator.

[0011]

In the high voltage terminal, a mounting plate for fixing the upper mounting bracket is provided, so that the lower surface of the mounting bracket is at least above the bottom surface of the high voltage terminal.
Further, since the insulating support posts are arranged so that the upper surface of the lower mounting bracket is at least lower than the upper surface of the ground potential plate, the equipotential surface can be made substantially horizontal at the upper end and the lower end. Therefore, it is possible to prevent the occurrence of corona and discharge at the upper end and the lower end.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ion accelerator according to an embodiment of the present invention will be described with reference to FIGS. Note that the same reference numerals are given to portions corresponding to the conventional example, and detailed description thereof is omitted.

That is, in this embodiment, the mounting plate 20 is disposed within the high-voltage terminal 2 at a predetermined height from the bottom wall of the high-voltage terminal 2 and is made of an insulating material for supporting the ion source 3 thereon. The support 13 is fixed. An upper mounting bracket 15 is fixed to the lower surface of the support 13 with screws 14. The upper end of the insulating support 12 has an opening 2 a formed in the bottom wall of the high-voltage terminal 2. As shown in the figure, the lower end is inserted through an opening 17a formed in the ground shield plate 17 fixed to the shield box 1, and the lower mounting bracket 16 fixed to the lower end is high. It is fixed to an adjustable plate 21 by screws 18. Although the plate 21 is fixed on the frame 11, the plate 21 can be moved up and down through the frame 11, that is, the height of the upper end of the insulating support 12 can be adjusted.

An embodiment of the present invention is configured as described above.
The normal operation is the same as that of the conventional example, but has the following effects.

That is, as shown in FIG. 2, the upper mounting bracket 15 is disposed so as to be located at least above the lower surface of the opening 2a formed in the bottom wall of the high-voltage terminal 2. In FIG. 2, the height of the lower surface of the high-voltage terminal 2 and the lower surface of the upper mounting bracket 15 can be the same, and in this case, the equipotential surface L can be substantially horizontal as shown in FIG. . That is, the corona and the discharge are prevented from being generated by the protruding shape of the equipotential surface as in the related art.

The lower mounting bracket 16 is also disposed so as to be located below the opening 17a formed in the ground shield plate 17, so that it does not have an equipotential surface protruding upward. A substantially horizontal equipotential surface can be provided, and the occurrence of electric discharge or corona at the lower end of the insulating column 12 can also be prevented.

Although the embodiment of the present invention has been described above, the present invention is, of course, not limited to this, and various modifications can be made based on the technical concept of the present invention.

That is, in the above embodiment, the detailed structure of the high voltage generator 5 is not shown, and the power supply device for supplying power to the ion source 3 and the mass separation magnet is not shown. The ion accelerator is arranged below the high voltage terminal 2 and the upper end thereof is inserted through an opening separately formed in the bottom wall of the high voltage terminal 2 so that the ion accelerator has a compact structure as a whole. You may.

[0019]

As described above, according to the ion accelerator of the present invention, the equipotential surfaces around the upper end and lower end of the insulating pillar made of ceramic at low cost are formed almost horizontally without distortion. It is possible to prevent corona and discharge from occurring.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view of an ion accelerator according to an embodiment of the present invention.

FIG. 2 is an enlarged side sectional view of the main part.

FIG. 3 is a schematic side sectional view of a conventional ion accelerator.

FIG. 4 is a schematic side view of an ion accelerator of a second conventional example.

FIG. 5 is an enlarged side view of a main part of a second conventional example.

[Explanation of symbols]

 2 High voltage terminal 12 Insulating column 15 Upper mounting bracket 16 Lower mounting bracket 17 Ground shield plate 20 Mounting plate

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-57-113600 (JP, A) JP-A-5-266995 (JP, A) JP-A-5-266994 (JP, A) JP-A-5-266994 334987 (JP, A) JP-A-5-299198 (JP, A) JP-A-5-283200 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05H 5/02

Claims (1)

(57) [Claims] 1. A casing containing at least an ion source and a mass separation magnet is supported on a floor at a predetermined height by a ceramic insulating column, and a high voltage power supply applies a predetermined high voltage to the casing. In an ion accelerator configured to supply power to the ion source, the mass separation magnet, and the like by a power supply device, an opening is formed in a bottom wall portion of the casing, and an upper mounting bracket fixed to an upper end portion of the insulating column. The mounting bracket projects from the opening into the casing so that the bottom surface of the lower mounting bracket is at least above the bottom surface of the casing, and the upper surface of the lower mounting bracket fixed to the lower end of the insulating support post is above the floor. The insulation is provided such that the opening formed in the plate is at least lower than the upper surface of the stretched ground potential plate and projects downward. An ion accelerator, wherein a column is provided, and the upper mounting bracket and the lower mounting bracket are fixed to a mounting plate and the floor provided in the casing, respectively.