JP3524277B2 - Neutral particle injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce thermal load injected in a beam damp and reduce the size of the beam damp. SOLUTION: This device has a neutralizing cell 4 converting ion beam 2 emitted from an ion source 1 to neutral particles, a biasing magnet 11 biasing the orbit of the ion beam 2 remaining after passing the neutralizing cell 4 and beam dumps 13a, 13b, 14a and 14b eliminating the remaining ion biased by the magnetic field of the bias magnet 11 as heat. Between the magnetic poles of the bias magnet 11, the beam dumps 13a and 13b are arranged so that the ion beam 2 goes into the beam dumps 13a and 13b before completely reflected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a neutral particle injector which is a heating device for a nuclear fusion device.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view showing the structure of a conventional neutral particle injector. As shown in FIG. 5, the ion beam 2 extracted from the ion source 1 is neutralized by passing through a vacuum container 3 and a neutralization cell 4. Only the neutral particles neutralized by the neutralization cell 4 are contained in the vacuum container 5.
Through the drift tube 6 and is incident on the plasma 8 of the nuclear fusion device body 7.

Further, in order to evacuate the inside of the vacuum container 3,
While the cryopump 9 is installed, the vacuum container 5
A calorimeter 10 therein, a deflection magnet 11 for deflecting the path of the ion beam 2, and a beam dump 1 for removing residual ions deflected by the deflection magnet 11 as heat.
2 and 12 are installed.

When the ion beam 2 passes through the neutralization cell 4 and is converted into a neutral particle beam, some of the ions remain as ions. The residual ions have their ion trajectories bent by the magnetic field of the deflection magnet 11 installed in the vacuum container 5, and enter the beam dumps 12 and 12 as a heat load to be removed.

Now, a method of deflecting the ion beam will be described. The ion beam deflection method is divided into a transmissive type and a reflective type. FIG. 6 shows a conventional transmissive type ion beam trajectory and beam dump configuration, and FIG. 7 shows a conventional reflective type ion beam. The orbit and beam dump configurations are shown respectively. However, in FIGS. 6 and 7, only the trajectory of the negative ion beam is shown, and the positive ions are not shown because they are vertically symmetrical with respect to the beam axis.

In the case of the transmission type, as shown in FIG. 6, the trajectory of the ion beam 2 is bent by the deflection magnet 11 and is incident on the beam dumps 12, 12. The transmissive beam dumps 12, 12 are arranged at positions substantially parallel to the beam axis for receiving the beam.

In the case of the reflection type, as shown in FIG. 7, the ion trajectory of the ion beam 2 is 180 due to the deflection magnet 11.
The beam dumps 12 and 12 are arranged at a position perpendicular to the beam axis because they are deflected.

The beam dumps 12 and 12 are installed with cooling pipes arranged side by side in the ion beam incident area. When a straight pipe is used depending on the value of the incident heat load, a twisting tape is inserted in the cooling pipe to remove heat. In some cases, an elevated swirl tube is used.

[0009]

However, in the conventional neutral particle injector described above, the beam dump 1
The structure of Nos. 2 and 12 has a problem in the thermal load of the incident ion beam 2 and the arrangement of the beam dumps 12 and 12 that receive it. Each problem will be described for each beam deflection method described above.

In the case of the transmission type deflection method, the ion beam 2 which has passed through the neutralization cell 4 as shown in FIG. 6 passes through the deflection magnet 11 and is thereafter converged by the magnetic field of the deflection magnet 11. The heat load per unit area when entering the beam dumps 12, 12 becomes high. In order to reduce this heat load, it is necessary to reduce the strength of the magnetic field of the deflection magnet 11 and make the incident angle of the ion beam 2 incident on the beam dumps 12, 12 shallow.

In this case, since the beam area expands in the beam axis direction, the length of the beam dumps 12, 12 must be increased. Also, long beam dumps 12, 12
Therefore, the vacuum container 5 must be enlarged. Further, if the beam dumps 12 and 12 become long, there is a problem that the pressure loss when flowing the cooling water increases and the pump capacity of the entire apparatus increases. And beam dump 1
There is also a problem that the thermal deformation caused by the temperature rise at the time of beam incidence becomes large because the lengths of 2 and 12 become long.

In the case of the reflection type deflection method, as shown in FIG. 7, the ion beam 2 is converged in the magnetic field region of the deflection magnet 11 and then diverged again so that the beam has a shape close to the beam distribution at the time of incidence. It is incident on the dumps 12, 12. Therefore, although the heat load can be kept low, the ion beam 2
Requires a magnetic field region for deflecting the beam by 180 °, which causes a problem that the deflection magnet 11 and the beam dumps 12 and 12 are increased in size.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a neutral particle injector in which the beam dump is downsized while reducing the heat load incident on the beam dump. And

[0014]

In order to solve the above-mentioned problems, the first aspect of the present invention is to provide an ion source for producing an ion beam, and an ion beam emitted from the ion source to neutral particles. Neutral particles having a neutralizing cell, a deflecting magnet for deflecting the trajectory of the ion beam remaining after passing through the neutralizing cell, and a beam dump for removing residual ions deflected by the magnetic field of the deflecting magnet as heat. In the injector, the beam dump is arranged between the magnetic poles of the deflection magnet substantially parallel to the beam axis of the ion beam.
Horizontal beam dump and the ion beam outside the deflection magnet.
Vertical beam dumps arranged perpendicular to the beam axis of the
The ion before being completely reflected while being composed of
The beam is incident on the horizontal beam dump and is totally reflected.
The ion beam is incident on the vertical beam dump.
Characterized in that that.

[0015]

According to a second aspect of the present invention, the beam dump has a cooling tube structure in which a swirl tube is provided in a high heat load portion by an ion beam and a straight tube is provided in a low heat load portion.

A third aspect of the present invention is characterized in that the cooling pipe provided in the low heat load portion has a double pipe structure.

[0018] Claim 4 is characterized with cooling water flowing in the beam dump receiving the high heat load, that the cooling water of the beam dump receiving the low thermal load has a structure to flow in series.

According to a fifth aspect of the present invention, the beam dump is characterized in that an anticorrosion coating is applied to the inner surface of the cooling pipe.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a first embodiment of a neutral particle injector according to the present invention. The same parts as those of the conventional configuration will be described with the same reference numerals as those in FIG.

As shown in FIG. 1, the neutral particle injector is
An ion source 1 for generating an ion beam 2, a neutralization cell 4 for converting the ion beam 2 emitted from the ion source 1 into neutral particles, and ions remaining after passing through the neutralization cell 4 are removed. A deflection magnet 11 for deflecting the trajectory of the ion beam 2 and a horizontal beam dump 13 for removing the residual ions deflected by the deflection magnet 11 as heat.
a, 13b and vertical beam dumps 14a, 14b,
It has a drift tube 6 through which the neutral particles pass before they enter the plasma 8 of the nuclear fusion device body 7.

The vacuum container 3 is evacuated .
A cryopump 9 is installed, and the deflection magnet 11 and the horizontal beam dumps 13a and 13b and the vertical beam dump 1 are installed.
4a and 14b are installed in the vacuum container 5.

Here, 13a is a horizontal beam dump for negative ions, 13b is a horizontal beam dump for positive ions, and 14 is a horizontal beam dump for positive ions.
“A” indicates a vertical beam dump for negative ions, and “14b” indicates a vertical beam dump for positive ions. The horizontal beam dumps 13a, 13b are installed in the magnetic pole gap of the deflection magnet 11, and the vertical beam dumps 14a,
14b is installed on the side of the neutralization cell 4 of the deflection magnet 11.

Next, the operation of this embodiment will be described.

The ion beam 2 extracted from the ion source 1 is converted into neutral particles through a neutralization cell 4. However, some of them remain as ions, and FIG. 1 shows only the remaining ion beam 2. When the converted neutral particles enter the plasma 8 of the fusion device 7,
After passing through the neutralization cell 4, the trajectory of the remaining ion beam 2 is bent by the magnetic field generated by the deflection magnet 11. This bent ion is then transferred to the horizontal beam dumps 13a, 13
b, incident on the vertical beam dumps 14a, 14b and removed as heat.

The deflected ion beam 2 is about 9
After being deflected by 0 °, it is incident on a horizontal beam dump 13a installed horizontally between the magnetic poles of the deflection magnet 11 and the beam orbit. Horizontal beam dumps 13a, 13 are provided between the deflection magnets 11.
By installing b, the ion beam 2 is incident on the horizontal beam dump 13a at a distribution point that is slightly narrower than the expansion at the time of leaving the neutralization cell 4, so that the dimension of the deflection magnet 11 in the height direction is reflected. It can be shorter than the mold.

However, the deflected ion beam 2 cannot be entirely received by the horizontal beam dump 13a alone.
Therefore, in order to receive the ion beam 2 that could not be received, the ion beam 2 is further deflected, and a vertical beam dump 14a is arranged in a portion passing through the magnet area in a direction perpendicular to the beam axis. Since the vertical beam dump 14a receives only the ion beam 2 that has not been incident on the horizontal beam dump 13a first, it suffices to cover an area shorter than the beam dump length in the case of the perfect reflection type.

By the way, there are two kinds of positive and negative ions in the ion beam due to electric charges. Although FIG. 1 does not show only one type of ion beam trajectory, the deflection method is reversed because the charges of the other type of ion beam are opposite to each other. Therefore, the horizontal ion beam dump 13 described above is used.
b and the vertical ion beam dump 14b are similarly arranged at positions with the beam axis as the axis of symmetry.

Therefore, the horizontal beam dump 13b for positive ions and the horizontal beam dump 13a for negative ions are installed in the gap of the deflection magnet 11, and the deflection magnet 11 is further provided.
Vertical beam dump 14b for positive ions on the side of the neutralization cell 4
And a vertical beam dump 14a for negative ions is installed.

As described above, according to the present embodiment, the horizontal beam dumps 13a and 13b are installed between the magnetic poles of the deflection magnet 11, and the ion beam 2 is made incident on the horizontal beam dump 13a before being completely reflected. The heat can be removed by the horizontal beam dump 13a without converging the beam 2. Further, the deflection magnet 11 can be downsized as compared with the perfect reflection type, and the vacuum container 5 can also be downsized.

Further, horizontal beam dumps 13a and 13b are installed between the deflection magnets 11 so as to be horizontal to the beam axis, and vertical beam dumps 14a and 14b are perpendicular to the beam axis.
By installing, the length of each beam dump can be shortened. Thereby, the pressure loss of the cooling water flowing in the beam dump can be reduced, and the thermal deformation due to the beam incidence can be suppressed.

Further, two beam dumps are provided for the horizontal beam dumps 13a and 13b and the vertical beam dumps 14a and 14b.
By adopting a divided structure, it is possible to form a unit and reduce the weight of one unit during assembly. This makes it possible to improve work efficiency during assembly and disassembly.

That is, by dividing the beam dump, when there is a difference in heat load due to the incidence of each beam, it is possible to employ a cooling structure that matches each heat load. In addition, when assembling and disassembling, the deflection magnet 11, the vertical beam dumps 14a and 14b, and the horizontal beam dumps 13a and 13b each become a unit.
The weight and shape of the unit are made compact.

2 (A) and 2 (B) are perspective views showing the cooling pipe of the beam dump in the second embodiment of the neutral particle injector according to the present invention. The portions corresponding to those in the first embodiment will be described with the same reference numerals. In the second embodiment, the configurations of the deflection magnet and the beam dump are the same as those in the first embodiment.

By the way, since the ion beam 2 which has passed through the neutralization cell 4 has a distribution, it does not have a uniform heat load in the beam region. Therefore, horizontal beam dump 1
The incident thermal loads are different between the vertical beam dumps 14a and 14b and the vertical beam dumps 14a and 14b. When the difference in the heat load value is large, the beam dump subjected to the high heat load uses the swirl tube 16 having the cooling capacity enhanced by inserting the twisting tape 15 inside the cooling tube as shown in FIG. 2 (A).

The swirl pipe 16 has a much higher heat removal capacity than a straight pipe, but has a large pressure loss when flowing cooling water. Therefore, as shown in FIG. 1, by splitting into horizontal beam dumps 13a and 13b and vertical beam dumps 14a and 14b, the length per one can be shortened and the pressure loss in each cooling unit can be reduced. .

When the difference in heat load between the horizontal beam dumps 13a and 13b and the vertical beam dumps 14a and 14b is large, a swirl tube 16 is used for the beam dump that receives a high heat load, and a beam dump with a low incident heat load is used. For this, a straight pipe 17 as shown in FIG. 2 (B) is used. By changing the cooling structure for each unit in this manner, it is possible to optimize the cooling water amount and the cooling water pressure.

As described above, according to this embodiment, the swirl pipe 16 is provided in the high heat load portion and the straight pipe 17 is provided in the low heat load portion.
By adopting the beam dump configuration using, it is possible to achieve a cooling configuration that matches the incident heat load, reduce losses, and optimize the cooling structure.

Further, the cooling water of the divided beam dump is made to flow in series from the high heat load portion to the low heat load portion, so that the required cooling water flow rate can be reduced while securing the cooling capacity, and the cooling structure is compact. Can be realized.

FIGS. 3 (A) and 3 (B) are a perspective view showing a beam dump in a third embodiment of the neutral particle injector according to the present invention and a sectional view showing its cooling pipe.

In this embodiment, a double tube is used as a beam dump for low-temperature heat load, as shown in FIGS. 3 (A) and 3 (B).
The double tube beam dump 18 shown in FIG. 2 is installed between the deflection magnets 11, and the header 19 is installed outside the deflection magnets 11.

As described above, according to this embodiment, since the double pipe beam dump 18 is used in the low heat load portion, the header for cooling water is required only on one side of the cooling pipe, and the overall structure is compact. It is possible to simplify the cooling pipe configuration in the vacuum container 5. Further, since the restraint against the thermal elongation is limited to one side, the stress due to the thermal deformation is reduced.

FIG. 4 is a sectional view showing a cooling pipe of a beam dump in a fourth embodiment of the neutral particle injector according to the present invention.

In this embodiment, when copper is used as the material of the cooling pipe 20, the inner surface of the cooling pipe 20 is coated with a corrosion-resistant thin film 21 such as titanium (Ti). By forming the thin film 21, it is possible to prevent erosion of the inner wall surface of the cooling pipe 20 while the cooling water flows. The lifetime of the beam dump is determined not only by repeated thermal stress but also by the above-mentioned erosion in the cooling pipe. Therefore, by coating the cooling pipe 20 with the thin film 21 of titanium (Ti), the replacement period of the beam dump can be extended and the maintenance period can be extended.

[0046]

As described above, according to the first aspect of the present invention.
According to the above, the beam dump is arranged between the magnetic poles of the deflection magnet, and the ion beam is made incident on the beam dump before being completely reflected, so that the heat load on the beam dump is reduced without converging the ion beam. It is possible to remove heat. Further, the deflection magnet and the beam dump can be downsized, and the vacuum container can also be downsized, as compared with the case of the complete reflection type.

Further, the neutral particle injector according to the present invention is
Water placed between the magnetic poles of the deflection magnet almost parallel to the beam axis
A flat beam dump and an ion beam outside the deflection magnet
With a vertical beam dump arranged perpendicular to the axis
Therefore, the ion beam before complete reflection is converted into a horizontal beam dump.
Ion beam after incident and completely reflected
Can be made incident on the pump. Therefore, in claim 1,
Beam dump without focusing the ion beam
It is possible to remove heat while reducing the heat load per hit.
In addition, since the beam dump has a divided structure, it can be unitized and the weight of one unit at the time of assembly can be reduced. As a result, work efficiency during assembly and disassembly can be improved.

According to the second aspect , the beam dump has the cooling pipe structure in which the swirl tube is provided in the high heat load portion due to the ion beam and the straight tube is provided in the low heat load portion. Configuration is possible,
Loss is reduced and the cooling structure can be optimized.

According to the third aspect , since the cooling pipe provided in the low heat load portion has the double pipe structure, the cooling pipe header of this cooling pipe is required only on one side, and the cooling pipe is simplified. You can Further, since the restraint against the thermal elongation is limited to one side, the stress due to the thermal deformation is reduced.

According to the fourth aspect of the present invention , the cooling water flowing through the beam dump that receives a high heat load and the cooling water flowing through the beam dump that receives a low heat load are made to flow in series. The flow rate of cooling water can be reduced, and the cooling structure can be made compact.

According to the fifth aspect of the present invention, the beam dump has the inner surface of the cooling pipe provided with the anticorrosion coating, so that the wall of the beam dump can be prevented from being eroded by the cooling water flow of the beam dump, and the period of use of the beam dump can be extended. The maintenance period can be extended.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a neutral particle injection device according to the present invention.

2A and 2B are perspective views showing a cooling pipe of a beam dump in a second embodiment of the neutral particle injection device according to the present invention.

3 (A) and 3 (B) are perspective views showing a beam dump in a third embodiment of the neutral particle injector according to the present invention,
Sectional drawing which shows the cooling pipe.

FIG. 4 is a sectional view showing a cooling pipe of a beam dump in a fourth embodiment of the neutral particle injection device according to the present invention.

FIG. 5 is a sectional view showing the structure of a conventional neutral particle injector.

FIG. 6 is a cross-sectional view showing a transmissive beam dump configuration in a conventional neutral particle injector.

FIG. 7 is a cross-sectional view showing a reflective beam dump configuration in a conventional neutral particle injector.

[Explanation of symbols]

1 ion source 2 ion beam 3 vacuum container 4 Neutralization cell 5 vacuum container 6 drift tube 7 Fusion device body 8 plasma 9 Cryo pump 11 Deflection magnet 13a, 13b Horizontal beam dump 14a, 14b Vertical beam dump 15 twisting tape 16 swirl tube 17 straight pipe 18 Double tube beam dump 19 header 20 cooling pipe 21 thin film

Claims (5)

(57) [Claims] 1. An ion source for generating an ion beam, a neutralizing cell for converting the ion beam emitted from the ion source into neutral particles, and an orbit of the ion beam remaining after passing through the neutralizing cell. In a neutral particle injector having a deflecting magnet for deflecting and a beam dump for removing residual ions deflected by the magnetic field of the deflecting magnet as heat,
The beam dump consists of the ions between the magnetic poles of the deflection magnet.
Horizontal beam holders arranged almost parallel to the beam axis of the beam
And the beam axis of the ion beam outside the deflection magnet
And a vertical beam dump arranged vertically
In addition, the ion beam before being completely reflected is the water.
The ion beam that was incident on the flat beam dump and was completely reflected
The apparatus for injecting neutral particles, wherein a beam is incident on the vertical beam dump . 2. The beam dump has a cooling pipe structure in which a swirl tube is provided in a high heat load portion due to an ion beam and a straight tube is provided in a low heat load portion, respectively.
Neutral particle injection device described. 3. The neutral particle injection device according to claim 2, wherein the cooling pipe provided in the low heat load portion has a double pipe structure. 4. The neutral particle injection device according to claim 2, wherein the cooling water to be passed through the beam dump that receives a high heat load and the cooling water for the beam dump that receives a low heat load are made to flow in series. 5. The neutral particle injector according to claim 1, wherein the beam dump is provided with an anticorrosion coating on the inner surface of the cooling pipe.