JPS583577B2 - Aeon Hatsei Souchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ion generator capable of achieving high output.

Recently, ion beams have been applied not only to the field of nuclear physics but also to various other fields.

An ion generator is required to obtain an ion beam, and various types of ion generators have been proposed in the past.

A typical example is one that utilizes the impact ionization of electrons caused by air discharge.

This type of ion generator has an anode and a cathode placed in a vacuum, generates a discharge between the two electrodes, and causes the electrons obtained by the discharge to collide with a specific gas, thereby ionizing the gas. has been done.

By the way, it would be very convenient if a high-output ion generator of this kind appeared.

However, in order to achieve high output, it is necessary to properly cool the cathode by some means.

That is, some of the generated ions collide with the cathode, and the input density to the cathode reaches, for example, 100 Kw/cm2.

Therefore, it is necessary to cool the cathode by some means, but at present there is no suitable means for achieving this, and for this reason, the reality is that there is no one with a high output.

The present invention was developed in view of the above circumstances, and its purpose is to suppress the amount of ions that collide with the cathode to a sufficiently small value, thereby facilitating cooling of the cathode and increasing output power. An object of the present invention is to provide an ion generator capable of achieving the following.

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

In FIG. 1, 1 in the figure is a vacuum container, and this container 1
A hole 2 is provided in a part of the wall.

A cylindrical container 3 is airtightly fixed to a flange 30 formed on the outer peripheral edge of the hole 2 so as to become a part of the wall of the container 1.

The cylindrical container 3 is made of an insulating material, and its internal space is formed in the shape of a frustum cone whose diameter decreases as it moves away from the container 1.

A cylindrical anode 4 is arranged coaxially within the cylindrical container 3.

The anode 4 is formed to have a smaller diameter as it goes upward in the figure, and the portion 4a other than both ends is formed of a material having gas permeability.

The upper end of the anode 4 in the figure is appropriately bent and fixed to the inner surface of the cylindrical container 3 in an airtight manner.

An insulating tube 5 is coaxially disposed between the inner surface of the cylindrical container 3 and the outer surface of the anode 4 to form a ring-shaped space between the cylindrical container 3 and the anode 4. Intervening.

The lower end of the insulating cylinder 5 in the figure is hermetically fixed to the flange 30 of the vacuum vessel 1, and the upper end in the figure is a free end so as not to come into contact with the inner surface of the upper end of the anode 4 in the figure. .

A cylindrical adjustment member 6 is fixed to the surface of the insulating tube 5 located on the anode 4 side for setting the space formed between the insulating tube 5 and the anode 4 to a predetermined value.

The lower end side of the adjustment member 6 in the figure is formed to have a thin wall so that its outer diameter decreases over a predetermined length, and due to the existence of this thin wall, a ring-shaped gap is formed between the adjustment member 6 and the insulating cylinder 5. A space 7 is formed.

A guide cylinder 8 made of an insulating material is provided so that its upper end fits into the space 7 without contact. is fixed.

Note that the lower part of the space formed between the guide cylinder 8 and the insulating cylinder 5 in the figure is connected to a gas discharge hole 9 formed in the wall of the container 1, and the insulating cylinder 5 and the cylindrical container 3 are connected to each other. The lower part of the space formed between the two is connected to a gas supply hole 10 also formed in the wall of the container 1.

Further, the lower end of the anode 4 in the figure is airtightly fixed to the inner surface of the guide cylinder 8 via a ring-shaped support member 11.

Therefore, near the upper and lower openings in the figure of the anode 4,
Cathodes 12 and 13 are provided to face these openings.

The cathode 12 is formed, for example, in the shape of a double disk, and is connected to a conductive pipe 1 which is provided by penetrating the earthen wall of the cylindrical container 3 in an airtight manner.
It is fixed at the tip of 4.

A cooling liquid flows through the conductive pipe 14, and the cathode 12 is cooled by this cooling liquid, while the cathode 13 is connected to the guide tube through a support member made of an insulating material (not shown). It is fixed to the inner surface of the body 8, and an ion extraction hole 15 is provided in the center thereof.

Although not shown, lead wires are connected to the anode 4 and the cathode 13, respectively, and these lead wires are drawn out through the cylindrical container 3 in an airtight and insulated state.

Thus, coils 16 and 17 are attached to the outer periphery of the cylindrical container 3.

The coil 16 is formed so that the winding layer in the direction orthogonal to the axial direction is the same at any position in the axial direction, and the coil 17 is formed so that the winding layer in the direction orthogonal to the axial direction is upward in the figure. It is formed so that it gradually increases towards the other side.

Both coils 16 and 17 are connected in series or in parallel to an excitation power source (not shown).

Note that 18 in the figure indicates a non-magnetic case that houses the coils 16 and 17.

Next, the operation of the apparatus of the present invention configured as described above will be explained.

First, the inside of the vacuum container 1 is evacuated by an evacuation device (not shown).
After exhausting to below Torr, the coils 16 and 17 are energized.

Next, when the anode 4 is connected to the positive pole of a DC high voltage power supply (not shown) and the cathodes 12 and 13 are connected to the negative pole of the same power supply, a cold cathode discharge occurs between the anode 4 and the cathodes 12 and 13, and this discharge It persists under the action of the magnetic field created by the coils 16,17.

In such a state, when the gas to be ionized is supplied through the gas supply hole 10, this gas rises through the ring-shaped space formed between the cylindrical container 3 and the insulating tube 5, and reaches the upper end of the insulating tube 5. It flows down through the space formed between the folded anode 4 and the adjustment member 6.

A part of the gas flowing during this period enters the anode 4, that is, the discharge space, through the gas permeable portion 4a formed in the anode 4.

On the other hand, after the remaining gas contacts the anode 4 and cools the anode 4, the space formed between the adjusting member 6 and the guide cylinder 8 and the space formed between the guide cylinder 8 and the insulating cylinder 5 is released. The gas is discharged from the gas discharge hole 9 through the space formed by the gas.

The gas that has entered the discharge space through the gas permeable portion 4a of the anode 4 is collided with electrons generated by the discharge and becomes ion-electron pairs.

The generated ions are extracted from the extraction hole 15 of the cathode 13 through the following route.

That is, FIG. 2 shows only the anode 4 and cathodes 12 and 13 in order to explain the movement of ions, and 21 in the figure shows the lines of magnetic force of the magnetic field generated by the coils 16 and 17.

Since the coils 16 and 17 are configured as described above, the magnetic flux density gradually decreases from the cathode 12 side to the cathode 13 side.

Thus, for example, the ions generated at the human point in FIG. 2 are accelerated in the direction of the symmetry axis by the electric field peculiar to high-voltage discharge in a magnetic field, and during this time their direction is bent by the magnetic field, so that they have a magnetic moment μm.

When the axis of symmetry of the anode 4 is the Z-axis and the cathode 13 side is in the positive direction, the ions are subjected to a force F in the Z-axis direction due to a spatial change in the magnetic field.

This force F is 0 when the magnetic flux density is B (B=IB1).
Therefore, the ions are accelerated in the positive direction, draw a trajectory 22, are extracted from the extraction hole 15 of the cathode 13, and become part of the ion beam in a trajectory 23.

On the other hand, if the ions generated at point B are subjected to a force directed in the negative direction on the Z axis due to collision with molecules or other causes, the following will occur.

In other words, the ions moving toward the cathode 12 are 24 in the figure.
As shown in , the direction is bent by the magnetic field as it progresses.

However, since the force F due to the spatial change in the magnetic field is applied downward in the figure, the velocity of the ions decreases due to this force F, and is finally reflected at the position shown at 25, after which it is directed toward the cathode 13. and is extracted from the extraction hole 15 in the same manner as in the case described above.

With this configuration, it is possible to prevent the generated ions from colliding with the cathode 12, thereby preventing the cathode 12 from being heated, allowing the cathode 12 to be sufficiently cooled, and extracting a high-output ion beam. can do.

That is, there is an advantage that the output power is not limited by the cooling capacity of the cathode 12.

Further, it is possible to suppress wear and deformation of the cathode 12 due to sputtering, prolong the life of the cathode 12, and obtain an ion beam that does not contain impurities.

Note that although the above embodiment is an example of cold cathode discharge, it can also be applied to hot cathode discharge.

It can also be applied to high voltage mode discharge.

Furthermore, the magnetic field and electrodes do not necessarily have to be axially symmetrical.

Further, although it is desirable that the direction of change in the magnetic field be constant, it may be locally reversed as long as the direction is constant in the dog part.

Furthermore, the anode and the magnetic field near the anode may be parallel or non-parallel.

As detailed above, according to the present invention, the traveling direction of the generated ions is regulated by the strength of the magnetic field to prevent them from colliding with the cathode, so that the cathode may be damaged by the collision of ions. It is possible to reliably prevent
It is possible to provide an ion generator that is small, has high output, and has a long life.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a diagram for explaining the operation of the embodiment. 1... Vacuum container, 3... Cylindrical container, 4
... Anode, 12.13 ... Cathode, 15
...Ion extraction hole, 16,17... Coil for magnetic field generation.

Claims (1)

[Claims] 1. A vacuum container, a cylindrical anode provided in the vacuum container, a first cathode provided opposite to one open end of the anode, and a first cathode provided opposite to the other open end of the anode. a second cathode provided with an ion extraction hole in the center; a high voltage application device for applying a high voltage between the anode and the first and second cathodes to cause a discharge; and means for supplying an ionized gas into a discharge space surrounded by a second cathode, and a magnetic flux density increasing in the discharge space in substantially the same direction as the axial direction of the anode and as it approaches the first cathode. An ion generator comprising: a magnetic field generator that applies a magnetic field.