JPH09306697A - Particle accelerator and its baking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To disuse a bellows as much possible especially in the connection assembly of a beam chamber in a particle accelerator and its baking. SOLUTION: When a particle accelerator is constituted by connecting in a ring shape many beam chambers, flange couplings 2, 2 are used, and variation in length of the accelerator in baking (heating) conducted for removing moisture or gas from the inner wall surface is suppressed, and each beam chamber 1 is firmly fixed with each supporting fixing means 3. The inner wall surface is treated with a moisture removing agent before baking, and the temperature of the baking is decreased to about 70 deg.C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a particle accelerator and a baking method performed before its use.

[0002]

2. Description of the Related Art Generally, a particle accelerator is formed in a ring shape by connecting a number of beam chambers, and a bellows is interposed between the beam chambers to cope with thermal expansion during baking.

[0003]

By the way, when the beam passes through the inside of the particle accelerator, a wall current is generated as a reaction, but when the bellows are present as in the conventional case, the uneven wall surface of the bellows causes the wall current to flow. There is a problem that it obstructs the smooth flow of.

Bellows are generally made of stainless steel,
An aluminum alloy is used in some cases, but a flange is often used instead of direct welding for connection with the beam chamber. The bellows is an expensive component because it satisfies such a function. Moreover, during beam operation, discharge occurs in the RF shield and, in some cases, beam irradiation causes problems such as melting of the bellows.

Therefore, the present invention is intended to eliminate the use of the bellows in the particle accelerator as much as possible, and appropriately fixes each beam chamber constituting the particle accelerator in order to cope with thermal expansion during baking. Is an issue. Another object of the present invention is to provide a method in which the baking processing temperature is set lower than in the conventional case and the movement of the beam chamber due to heat can be suppressed.

[0006]

In order to solve the above-mentioned problems, the present invention provides a particle accelerator in which a plurality of beam chambers are airtightly connected to each other to form a ring shape and the inside is in a vacuum state. Each of the beam chambers is fixed so that the length thereof does not change during baking, and the beam chambers are connected to each other by a flange joint.

Further, the particle accelerator of the present invention is characterized in that the center portion of each beam chamber is fixed in order to properly fix the above-mentioned many beam chambers.

Further, the particle accelerator of the present invention is characterized in that the flange joint portions of the beam chambers are fixed to each other.

As described above, in the particle accelerator of the present invention, each beam chamber itself is fixed so as to withstand thermal expansion during baking so that the length does not change. Therefore, the conventional bellows is used. Can be eliminated as much as possible, whereby the flow of wall current can be made smooth, and the use of expensive bellows can be reduced as much as possible to achieve cost reduction.

On the other hand, in the particle accelerator baking method of the present invention, water is removed from the inner wall surface of the beam chamber by a water removing agent in advance during the baking process, and then the beam chamber is baked at about 70.degree. It is characterized by that. By setting the baking temperature extremely low as described above, it becomes easy to suppress the change in the length of the beam chamber, which can contribute to the elimination of the use of the bellows. Further, it is preferable to use dichloropropane as the water removing agent, which allows water to be efficiently removed from the inner wall surface of the beam chamber.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A particle accelerator and a baking method therefor according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a part of the particle accelerator according to the first embodiment of the present invention. FIG. 2 is a plan view showing a part of the particle accelerator as the second embodiment of the present invention.

As shown in FIGS. 1 and 2, in each of the embodiments, the particle accelerator is formed in a ring shape as a whole by hermetically connecting a large number of beam chambers 1 to each other via flanges 2. ing. Further, in the first embodiment of FIG. 1, each beam chamber 1 is firmly fixed at the central portion by the support fixing means 3, while in the second embodiment of FIG. 2, each beam chamber 1 supports and fixes the flange joint portion. It is firmly fixed by the means 3. In addition, each support fixing means 3 can be attached and detached with a bolt or a wedge.

In using the particle accelerator as described above,
The gas and moisture contained in the inner wall surface of each beam chamber 1 is removed by baking (heating) as a pretreatment for making the inside into an ultrahigh vacuum. At that time, the length of each beam chamber 1 due to thermal expansion is increased. Is sufficiently suppressed by the fixing action of each supporting and fixing means 3, so that a stable balance state of the internal compressive stress in the wall portion of each beam chamber 1 is generated.

In particular, in the particle accelerator baking method of the present invention, since the water on the inner wall surface is removed in advance by the water removing agent, the baking temperature required to remove the gas contained in the inner wall surface is about 70 ° C. At such a baking temperature, the internal compressive stress generated in each beam chamber 1 is 7 kg / m when the material of the chamber 1 is aluminum alloy.
Since the allowable stress is about m ² and the allowable stress is not exceeded, the beam chambers 1 can withstand baking without changing the length and without moving with respect to the central axis. Further, it is desirable to use dichloropropane as the water-removing agent, and when this is used, the water can be removed extremely efficiently and quickly.

As described above, according to the particle accelerator and the baking method thereof of the present invention, it is possible to eliminate the use of expensive bellows when connecting and assembling a large number of beam chambers as much as possible, thereby reducing the construction cost. In addition, the flow of the wall current when the particle accelerator is used can be smoothly performed because there is no bellows, which can contribute to the performance improvement of the particle accelerator.

[0016]

As described in detail above, according to the particle accelerator of the present invention and the baking method thereof, the following effects can be obtained. (1) Since each beam chamber itself is fixed to withstand thermal expansion during baking so that the length does not change, it is possible to eliminate the use of conventional bellows as much as possible. In addition to the smooth flow of wall current, it is possible to reduce the cost by reducing the use of expensive bellows as much as possible. (2) When baking the particle accelerator, water is removed from the inner wall surface of the beam chamber with a water remover in advance,
Then, by baking the beam chambers at approximately 70 ° C, it becomes easier to maintain the position of each beam chamber and the use of bellows in the particle accelerator is greatly suppressed, so that the performance of the particle accelerator is greatly improved. Be expected. (3) When dichloropropane is used as the water removing agent, water can be easily removed from the inner wall surface of the beam chamber, which can contribute to a reduction in baking temperature.

[Brief description of drawings]

FIG. 1 is a plan view showing a part of a particle accelerator as a first embodiment of the present invention.

FIG. 2 is a plan view showing a part of a particle accelerator as a second embodiment of the present invention.

[Explanation of symbols]

 1 beam chamber 2 flange 3 support fixing means

Claims (5)

[Claims] 1. A particle accelerator in which a plurality of beam chambers are hermetically connected to each other in a ring shape and whose inside is in a vacuum state, wherein each of the beam chambers is fixed so as not to change its length during baking. The particle accelerator, wherein the beam chambers are connected to each other by a flange joint. 2. The particle accelerator according to claim 1, wherein
A particle accelerator, wherein the central portion of the beam chamber is fixed. 3. The particle accelerator according to claim 1, wherein:
A particle accelerator, wherein the flange joints of the beam chambers are fixed to each other. 4. The particle accelerator according to claim 1, wherein water is removed from the inner wall surface of the beam chamber with a water removing agent in advance during the baking treatment of the particle accelerator, and then the beam chamber is baked at about 70 ° C. Baking method. 5. The baking method for a particle accelerator according to claim 4, wherein dichloropropane is used as the water removing agent.