JPH0750638B2 - Electric field generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric field generator that can be used as, for example, an accelerator tube of a charged particle accelerator.

[Conventional technology]

Appl. Phys. Lett. Vol. 45 No. 12 1984 1
Feb. 15 pp. 1287-1288 and J. Appl. Phys. Vol. 57 No. 11
There is an electron beam accelerator as shown on pages 5012-5016 of June 1, 1985, and a necessary electric field distribution can be obtained by passing a current through a plurality of electrode structures and resistors electrically contacting them. However, the structure is complicated, and particularly in the case of the technique shown in the latter document, the required electric field distribution is realized by giving each electrode a different curved surface structure.

[Problems to be solved by the invention]

The conventional electric field generator applied as an accelerating tube has a large number of parts because it is composed of a plurality of electrodes. In addition, the structure of each electrode must be very complicated because each electrode must have a unique curve. Further, since it is divided by a finite number of electrodes, there is a drawback that it is difficult to improve the accuracy of electric field distribution.

[Means for solving problems]

The above-mentioned problems can be solved by the electric field generator of the present invention, which is composed of a tubular body made of a volume-resistant material having plasticity, and electrodes provided at both ends of the tubular body.

A conductive ceramic, a ceramic containing a conductive material, a cement containing a conductive material, or the like can be used as the volume-resistant material whose raw material has plasticity. Carbon can be used as the conductive substance, and an appropriate amount can be used so as to obtain a desired resistance value. The volume resistance material needs to have hardness after being formed, but it is preferable that it can be machined after being hardened. Furthermore, if it has a vacuum sealing property after curing, it can be used as it is for an accelerating tube.

[Action]

The electric field generating device of the present invention uses a tubular body integrally formed of a volume resistance material, and a current is directly applied to the tubular body so that a complicated electric field for accelerating and converging charged particles is generated inside the tubular body. A distribution can be generated. When only the outer diameter of the tubular body is partially changed, that is, when the outer diameter is large, the electric field inside the tubular body becomes smaller than when the outer diameter is small. On the contrary, the electric field in the tubular body becomes larger at a portion having a smaller outer diameter than at a portion having a larger outer diameter. An arbitrary electric field distribution can be formed by continuously changing the outer diameter.

〔The invention's effect〕

Since the tubular body of the electric field generator of the present invention is formed of a volume resistance material, the structure of the electric field generator can be extremely simplified, but the electric field distribution inside is determined by the mechanical precision of the diameter. There is an effect that the electric field distribution can be accurately generated. When applied as an accelerating tube for accelerating charged particles, one tubular body has all the functions required for the accelerating tube structure: the accelerating effect, the converging effect, and the sky retention. Furthermore, since the raw material of the volume resistance material has plasticity, there is an advantage that it is extremely easy to produce a tubular body. Further, it is possible to reduce the size of the device that can reduce the diameter of the accelerating tube to about one third as compared with the conventional one.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples. 1a
FIGS. 1a to 1c are schematic views of the electric field generator of the present invention in various forms, and FIGS. 2a to 2c show potential distributions corresponding to the electric field generators of FIGS. 1a to 1c, respectively. Figure, first
3a to 3c are diagrams showing potential distributions corresponding to the electric field generators of FIGS. 1a to 1c, respectively. A power source 2 via switches 3 at both ends of an electric field generator having a tubular body 1.
When a voltage is applied by, a current flows in the tubular body 1. As a result, an electric field that is proportional to the product of the resistivity per unit length and the current flowing through the tubular body 1 is generated inside the tubular body 1 at that position. When the inner and outer diameters of the tubular body 1 are constant as shown in FIG. 1a, the potential is the tubular body 1 as shown in FIG. 2a.
The value of the electric field is constant as shown in FIG. 3a. As shown in FIG. 1b, when the outer diameter of the tubular body 1 is partially changed, the smaller the outer diameter is, the larger the resistivity is, and thus the smaller the outer diameter is, as shown in FIG. 2b. The potential change is also large. Also, the electric field becomes smaller when the outer diameter changes and becomes larger when the outer diameter changes, as shown in FIG. 3b. As shown in Figure 1c,
When the outer diameter of the tubular body 1 is gradually changed, as shown in FIGS. 2c and 3c, the electric potential and the electric field distribution are continuously changed accordingly. Curves I and II in FIG. 4 are measured examples of electric potentials corresponding to the tubular body shapes in FIGS. 1a and b. Curve I corresponds to the shape in FIG.
It matches the shape in Figure 2b. Therefore, the required potential and electric field distribution can be obtained extremely easily as expected.

FIG. 5 is a side sectional view when the electric field generator of the present invention is used as an accelerating tube. Electrodes 5 and 6 are provided at both ends of the tubular body 1. An electron source 7 is provided at the end where the electrode 5 is provided.
And an opening 9 through which an electron beam 8 generated from an electron source 7 passes is provided in the electrode 6. A high voltage (-1M) is applied to the electrode 5 and the electron source 7 via a line 10.
V) is applied. A vacuum pump is connected to the end of the exhaust pipe 11 so that the inside of the tubular body 1 is vacuumed. Insulating oil 12 is filled between the electrode 6 having a tubular shape with ends and the tubular body 1.
The inner wall of the tubular body 1 is coated with alumina. Further, the electrical contact portions on both ends of the tubular body 1 which is an accelerating tube are made of a silver paste (conductive adhesive. As the tubular body 1, 3Al ₂ O ₃ · 2SiO ₂ + α-Al ₂ O ₃ is carbon What is formed by firing the added material at 1200 ° C. The tubular body has a length of 40 cm, an outer diameter of 5 cmφ, an inner diameter of 4 cmφ, and a resistance value of 5 KΩ. The figure further shows a graph of the measured potential change in the axial direction of the tubular body 1.

[Brief description of drawings]

1a to 1c are schematic views of the electric field generator of the present invention in various forms, and FIGS. 2a to 2c show potential distributions corresponding to the electric field generators of FIGS. 1a to 1c, respectively. Figures, Figures 3a to 3c show electric field distributions corresponding to the electric field generators of Figures 1a to 1c respectively, and Figure 4 corresponds to the tubular body shape of Figures 1a and 1b. FIG. 5 is a side sectional view when the electric field generator of the present invention is used as an accelerating tube, and FIG. 6 is a graph of potential change in the axial direction of the tubular body of FIG. . 1 ... Tubular body, 5,6 ... Electrode, 7 ... Electron source, 8 ... Electron beam, 9 ... Aperture, 12 ... Insulating oil.

Claims (4)

[Claims] 1. An electric field generator comprising a tubular body made of a volume-resistant material having plasticity, and electrodes provided at both ends of the tubular body. 2. The electric field generator according to claim 1, wherein the electrode is provided with an opening for passing charged particles. 3. The electric field generating device according to claim 1, wherein the resistance material is a ceramic containing a trace amount of a conductive substance. 4. The electric field generating device according to claim 1, wherein the resistance material is cement containing a trace amount of a conductive substance.