JP3168785B2 - Vacuum beam duct for accelerator and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accelerator, and more particularly to a vacuum beam duct for an accelerator suitable for use as a duct for passing a particle beam in a large-scale accelerator such as a super large superconducting accelerator, and a method of manufacturing the same. It is.

[0002]

2. Description of the Related Art In recent years, for the purpose of studying various phenomena related to high energy physics, electron-electron collision, electron-
Accelerators have been developed to generate high energy particle collisions, such as positron collisions, proton-proton collisions, and the like. For example, an ultra-large superconducting accelerator (hereinafter, referred to as SSC) for generating proton-proton collisions is a circular accelerator for colliding protons accelerated to an energy of 20 trillion electron volts. The duct through which the proton beam passes in the SSC is a ring formed by connecting a number of vacuum beam ducts of a predetermined length, and the proton beam is deflected by a superconducting electromagnet installed in the middle of the ring. , While converging, it goes around the ring. In this case, a vacuum beam duct is disposed at the center of the superconducting electromagnet in a low-temperature atmosphere, and a proton beam passes through the inside thereof. Also, SSC
In, for example, the circumference of the ring is 87 km,
This is a large-scale one in which 10,000 or more superconducting electromagnets having a length of 16 m are used.

In the vacuum beam duct, accelerated protons collide with particles remaining in the beam duct, and hydrogen atoms are generated. Since the hydrogen atoms have an adverse effect such as hindering the movement of protons or lowering the degree of vacuum in the beam duct, it is necessary to remove generated hydrogen atoms by adsorbing them on the inner surface of the beam duct. Therefore, as a duct used in the SSC, as shown in FIG. 11, pump chambers 3 and 3 are provided inside the tube wall 2 of the beam duct 1 and a cryo absorber (low temperature adsorbent) is provided at the end thereof.
4, 4,... Are being studied.
A large number of pump holes 6, 6,... Are formed in a wall portion 5 that partitions the inside of the beam duct 1 from the pump chamber 3. In the beam duct 1 having such a structure, the generated hydrogen atoms reach the pump chamber 3 from the inside of the beam duct 1 through the pump hole 6, are adsorbed by the cryoabsorber 4, and are removed.

In order to manufacture a vacuum beam duct in which the pump chamber 3 is provided, a tubular beam duct 1 is formed from a metal such as an aluminum alloy by an extrusion method, and the tube wall 2 is formed on the tube beam 2. It is considered that the pump chamber 3 is formed, and thereafter, the pump holes 6 are formed one by one in the wall portion 5 that separates the inside of the beam duct 1 and the pump chamber 3 by press working.

[0005]

In a vacuum beam duct, a large number of pump holes are required because it is necessary to immediately adsorb the hydrogen atoms generated inside. For example, in the case of a 16 m long beam duct for SSC, about 450 pump holes are required,
In order to form such a large number of pump holes by press working, there is a problem that a very large number of steps are required.
On the other hand, when performing the press working, as the working progresses from the end portion of the beam duct to the center portion, a pair of punches for punching are inserted deep into the long beam duct to perform positioning and operation with high precision. There is a need. Further, when the volume of the pump chamber is small, there is a problem that it is difficult to insert a punch for punching or to discharge metal scraps at the time of punching to the outside. That is, the formation of the pump hole is an operation having difficulty as a technology of the press device.

On the other hand, the shape, size, position, etc. of the pump hole affect the high frequency flowing on the wall surface of the beam duct and, consequently, the stability of the orbit of the proton beam.
As described above, since the degree of freedom in designing the shape, size, and position of the pump hole is small because processing is extremely difficult, it is difficult to reduce the influence of high frequency flowing through the wall surface of the beam duct. As a result, there was concern that the orbit of the proton beam would be slightly unstable.

The present invention has been made in order to solve the above-mentioned problems, and provides a vacuum beam duct for an accelerator having high stability of the trajectory of a particle beam.
It is an object of the present invention to provide a method of manufacturing a vacuum beam duct for an accelerator, in which a pump hole having an arbitrary size and number can be easily formed.

[0008]

According to a first aspect of the present invention, there is provided a vacuum beam duct for an accelerator, wherein a beam chamber and a pump chamber are divided by a partition wall. The part is provided with a pump hole for communicating the beam chamber and the pump chamber, and is constituted by a brazing panel in which a brazing material is laminated on one or both sides of a base material plate.

According to a second aspect of the present invention, there is provided a method for manufacturing a vacuum beam duct for an accelerator, wherein a main body wall of a tubular beam duct main body is manufactured by an extrusion molding method.
At this time, a pair of partition walls protruding from the main body wall and facing each other, extending in the longitudinal direction of the beam duct main body, and between which an opening communicating with the pump chamber is secured is formed. Thereby, the beam duct main body including the main body wall portion and the pair of partition wall portions is manufactured, and the brazing panel in which the brazing material is laminated on one or both surfaces of the base material plate forms the pair of partition walls. A lid formed in a shape capable of closing the opening by contacting the opening, then forming a pump hole in the lid, and then closing the opening formed in the beam duct main body so as to close the opening. A lid is attached, and then the beam duct body to which the lid is attached is charged into a heating furnace and heated to melt the brazing material of the lid, and the pair of partition walls and the lid And brazing It is characterized in that integrating these Te.

[0010]

According to the vacuum beam duct for an accelerator according to the present invention, since a part of the partition wall for separating the beam chamber and the pump chamber is constituted by the brazing panel, the brazing is performed separately from the beam duct main body. A pump hole can be formed in the panel.

Further, according to the method of manufacturing a vacuum beam duct for an accelerator according to the second aspect, separately from the manufacturing of the beam duct main body having the pair of partition walls formed therein, the operation of manufacturing a lid body made of a brazing panel is performed. In addition, since the pump hole forming operation of the lid can be performed, the pump hole forming operation can be particularly easily performed by using any method.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a vacuum beam duct for an accelerator according to the present invention and a method for manufacturing the same will be described below with reference to FIGS. The vacuum beam duct for the accelerator of this embodiment is:
It is a tube made of an aluminum alloy having a diameter of 44 mm, a length of about 16 m, and a plate thickness of 2 mm, which is installed in an SSC superconducting electromagnet. A pump chamber is provided. FIG. 1 is a view showing a pump chamber portion provided at a lower portion in a beam duct 6, wherein reference numeral 7 denotes a pump chamber, 8 denotes a beam duct main body wall, 9
Is a partition wall, 10 is a lid plate (lid), 11 is a pump hole, and 12 is a cryoabsorber (low temperature adsorbent).

The beam duct main body wall 8 has a pair of partition walls 9 extending in the longitudinal direction of the beam duct 6 so as to face each other and projecting horizontally from the beam duct main body wall 8.
9 are formed. A notch 9a is formed in the upper end of each of the pair of partition walls 9, 9, and a cover plate 10 in which a number of pump holes 11 are formed at regular intervals is mounted on the notch 9a. And a pair of partition walls 9,
9 is integrated. Therefore, the inside of the pipe of the beam duct 6 is divided into the beam chamber 13 and the pump chamber 7 having an arc-shaped cross section by the integrated partition walls 9, 9 and the cover plate 10. Is communicated through a pump hole 11.

Both ends of the pump chamber 7 are filled with cryo-absorbers 12, 12, respectively. The cryoabsorber 12 is a porous adsorbent having a large surface area, and is made of, for example, titanium sponge or graphite, and has a property of adsorbing hydrogen atoms on the surface thereof in a low-temperature atmosphere.

Next, a method of manufacturing the beam duct having the above-described configuration will be described. FIG. 6 is a flowchart showing the manufacturing process. As shown in this figure, the beam duct is manufactured by separately manufacturing the beam duct main body and the cover plate, and thereafter, these are combined and integrated. I have.

First, the beam duct body 14 is manufactured.
In this case, as shown in FIG. 2, a beam duct main body 14 having a pair of partition walls 9, 9 provided with notches 9a at two upper and lower portions is manufactured by an extrusion method using an aluminum alloy as a material. (S1 in FIG. 6).

On the other hand, separately from the manufacture of the beam duct body 14, the cover plate 10 shown in FIG. 3 is manufactured. In this case, the material of the cover plate 10 is one side (or both sides) of the base material plate.
A commercially available brazing panel obtained by laminating a brazing material having a lower melting point than the base material plate is used (for example, JISZ326
BA23PC specified in No. 3). Then, the brazing panel is cut and formed into a size that fits into the notch 9a formed in the pair of partition walls 9, 9 of the beam duct main body 14 (S2 in FIG. 6). Thereafter, a large number of pump holes 11 are formed in the cover plate 10 by pressing at regular intervals (S3 in FIG. 6).

Next, as shown in FIG. 4, the cover plate 10 in which the pump hole 11 is formed is placed on the pair of partition walls 9 of the beam duct body 14 such that the surface on the brazing material side faces the pump chamber.
9 are fitted into the notches 9a, 9a formed therein, and are fixed by a holding jig (not shown) (S4 in FIG. 6).

Next, as shown in FIG. 5, the beam duct main body 14 having the lid plates 10 and 10 attached to the upper and lower two pump chambers 7 and 7 is charged into a vacuum heating furnace (heating furnace). Heat the whole. In this way, the brazing material of the brazing panel constituting the lid plate 10 is melted, so that the lid plate 10 and the pair of partition walls 9, 9 are integrated by brazing (S5 in FIG. 6). At this time, a force is applied in the direction shown by arrow 16 using the holding jig,
Each cover plate 10 is inserted into a vacuum heating furnace in a state where the cover plate 10 is pressed in the direction of the pair of partition walls 9 and 9.

Next, when the beam duct body 14 with the cover plate 10 integrated therein is subjected to a heat treatment at 180 ° C. for 20 hours (S6 in FIG. 6), the beam duct body 14 and the cover plate 1 are heated.
The production of the beam duct 6 is completed when the strength of the entirety is improved and reaches a predetermined strength. Thereafter, both ends of the pump chamber 7 are filled with a cryo-absorber 12.

The beam duct 6 thus manufactured
Is installed in the superconducting electromagnet of the SSC, the entire beam duct 6 is placed in a low-temperature atmosphere. When the proton beam passes through the center of the beam duct 6, it collides with particles remaining in the duct. The generated hydrogen atoms reach the pump chamber 7 through the pump hole 11. Therefore, the hydrogen atom is a cryoabsorber 1 that has the ability to adsorb at low temperatures.
2 and is removed from the beam chamber 13 of the beam duct 6. When the adsorbability of the cryoabsorber 12 decreases due to repeated use of SSC, the cryoabsorber 12 is regenerated by performing baking.

In the method of manufacturing the vacuum beam duct 6 for the accelerator according to the present embodiment, the cover plate 10 is manufactured outside the beam duct main body 14 separately from the manufacture of the beam duct main body 14, so that it is deep in the beam duct. The work of forming the pump hole 11 in the cover plate 10 by press working can be easily performed as compared with the conventional method of forming a pump hole by inserting a press device into the pump plate. Furthermore, cover plate 1
0 can be fitted into the notches 9a, 9a of the pair of partition walls 9, 9, so that the positioning of the lid plate 10 is easy, and the lid plate 10 is simply inserted into the vacuum heating furnace. Since they can be brazed to the portion 9 and integrated therewith, the fixing of the cover plate 10 can be performed easily and with a small number of steps. Therefore, according to this manufacturing method, it is possible to reduce man-hours and simplify the work throughout the entire manufacturing process of the beam duct 6.

Further, not only the work of forming the pump hole is facilitated, but also a large number of small pump holes 11 can be formed with high precision. Without adverse effects such as the generation of cavities,
The trajectory of the proton beam can be made more stable.

Since the extrusion molding method using an aluminum alloy as a raw material has been significantly improved, especially when forming the notch 9a in the partition wall 9 of the beam duct main body 14, high dimensional accuracy is required. When the lid plate 10 is mounted, the beam chamber 13 can be manufactured.
Can be made a smooth surface.

In the vacuum beam duct 6 for the accelerator according to the present embodiment, a notch 9a is formed at the tip of the partition wall 9 on the side of the beam chamber 13 in the shape of the joint between the partition wall 9 and the cover plate 10. Although the cover plate 10 is fitted into the notch 9a, various structures shown in FIGS. 7 to 10 can be applied instead.

FIG. 7 shows a beam duct 17 having a structure in which grooves 18a, 18a are formed in the center of the pair of partition walls 18, 18 in the plate thickness direction, and the lid plate 10 is fitted into the grooves 18a. . In the case of this structure, the cover plate 10 is firmly held by the partition walls 18 from both sides thereof.

FIG. 8 shows a pair of partition walls 2 such that a corner 20a at the end of the partition wall 20 on the pump chamber 7 side is acute.
A structure in which 0 and 20 are formed in a tapered shape, and the side surface of the lid plate 21 is also formed in a tapered shape like the partition wall portion 20, and the lid plate 21 is fitted between the pair of partition wall portions 20 and 20. The beam duct 19 of FIG. In the case of this structure, the cover plate 21
When the brazing material flows into the joint surface, the lid plate 21 and the partition wall portion 20 are integrated.

FIG. 9 shows the partition wall 2 so that the surfaces of the pair of partition walls 23 and 23 and the brazing material surface of the cover plate 24 are in contact with each other.
3 is a beam duct 22 having a structure in which a cover plate 24 is disposed on and integrated with them. In the case of this structure, the cover plate 2
There is no need to form the front end of the partition wall portion 23 for fitting with 4, and the distance between the pair of partition wall portions 23 and 23 and the dimension of the cover plate 24 do not require high precision.

FIG. 10 shows an example in which the shape of the beam duct itself is applied to an accelerator different from that described above.
(A) has a structure in which the inside of a beam duct 25 having a substantially rectangular cross section is divided into three chambers, and a beam chamber 26 is provided at the center, and pump chambers 27 and 27 are provided above and below the chamber. And
The main body wall 28 of the beam duct 25 has a pair of partition walls 2.
9 and 29 are formed on the upper and lower sides, and a pair of partition walls 29 and 2
9, similarly to FIG. 9, the cover plate 30 is disposed such that the surfaces of the pair of partition walls 29, 29 and the brazing material surface of the cover plate 30 abut against each other.
And a beam duct 25 having a structure integrating them.
It is. (B) has the same joining shape of the partition wall and the cover plate as in (a), and divides the inside of the beam duct 31 into two chambers, one of which is a beam chamber 32.
The other is a structure having a pump chamber 33. Even if the beam ducts have different shapes as described above, the beam ducts can be manufactured through exactly the same steps as described above.

In this manufacturing method, since the cover plate 10 is manufactured separately from the beam duct main body 14, various methods can be used for forming the pump hole. In the present embodiment, press working is used, but instead of this method, for example, mechanical working, working with an electron beam, laser, or the like can be used.

[0031]

As described in detail above, claim 1 is as follows.
According to the accelerator vacuum beam duct described above, since a part of the partition wall that separates the beam chamber and the pump chamber is constituted by the brazing panel, a pump hole is formed in the brazing panel separately from the main body of the beam duct. Can be done. Therefore, the degree of freedom in pump hole design can be improved, and the high frequency flowing through the wall surface of the beam duct can be stabilized. As a result, the orbit of the proton beam can be further stabilized.

In the method of manufacturing a vacuum beam duct for an accelerator according to the second aspect of the present invention, since the lid is manufactured separately from the manufacturing of the beam duct main body, the pump is inserted deep into the beam duct. As compared with the conventional method in which holes are formed, the operation of forming the pump holes in the lid can be easily performed. Furthermore, after attaching the lid consisting of the brazing panel to the beam duct body,
The lid can be brazed to the pair of partition walls of the beam duct body simply by being charged into the heating furnace, and these can be integrated, so that the lid can be fixed easily and with a small number of man-hours. . Therefore, according to the manufacturing method of the present invention, a reduction in man-hours throughout the manufacturing process of the beam duct,
Work can be simplified.

[Brief description of the drawings]

FIG. 1 is an enlarged perspective view of a pump chamber in an embodiment of a vacuum beam duct for an accelerator according to the present invention.

FIG. 2 is a perspective view showing a beam duct main body in the embodiment.

FIG. 3 is a perspective view showing a cover plate in the embodiment.

FIG. 4 is a perspective view showing a state in which a cover plate is mounted on a beam duct main body in the embodiment.

FIG. 5 is a cross-sectional view showing a state in which a beam duct main body with a cover plate mounted therein is charged into a vacuum heating furnace in the embodiment.

FIG. 6 is a flowchart showing a procedure of a method of manufacturing a vacuum beam duct for an accelerator according to the present invention.

FIG. 7 is a sectional view showing another embodiment of the joint structure between the pair of partition walls and the cover plate in the embodiment.

FIG. 8 is a sectional view showing another embodiment of the present invention.

FIG. 9 is a sectional view showing another embodiment of the present invention.

FIGS. 10A and 10B are cross-sectional views showing a joint structure between a pair of partition walls and a cover plate when the present invention is applied to a beam duct having another shape, wherein FIG. 10A shows two pump chambers and FIG. This is a case where one pump chamber is provided.

FIG. 11 is a perspective view showing an example of a beam duct being studied to be applied to the SSC.

[Explanation of symbols]

6, 17, 19, 22, 25, 31 ... beam duct (vacuum beam duct for accelerator) 7, 27, 33 ... pump chamber 8, 28 ... beam duct main body wall 9, 18, 20, 23, 29 ... partition wall Part 10, 21, 24, 30 ... lid plate (lid) 11 ... pump hole 13, 26, 32 ... beam chamber 14 ... beam duct body

Claims (2)

(57) [Claims] 1. An electromagnet which constitutes an accelerator,
An accelerator vacuum beam duct composed of a beam chamber for passing a particle beam therein and a pump chamber for adsorbing particles remaining in the beam chamber, wherein the beam chamber and the pump chamber are separated by a partition wall. A part of the partition wall portion is formed by a brazing panel in which a pump hole for communicating the beam chamber and the pump chamber is provided, and a brazing material is laminated on one or both surfaces of a base material plate. A vacuum beam duct for an accelerator. 2. An electromagnet constituting an accelerator,
A method for manufacturing a vacuum beam duct for an accelerator, comprising a beam chamber through which a particle beam passes and a pump chamber to adsorb particles remaining in the beam chamber, wherein a tubular beam duct body is formed by extrusion molding. In this case, the main body wall portion is manufactured, and at this time, an opening protruding from the main body wall portion and facing each other, extending in the longitudinal direction of the beam duct main body, and communicating with the pump chamber is secured therebetween. By forming the pair of partition walls, the beam duct body including the main body wall and the pair of partition walls is manufactured, and a brazing material is laminated on one or both surfaces of the base material plate. By using a brazing panel, a lid formed in a shape capable of contacting the pair of partition walls and closing the opening is manufactured. Then, the lid is attached so as to close the opening formed in the beam duct main body, and then the beam duct main body with the lid attached is charged into a heating furnace and heated. A method of manufacturing a vacuum beam duct for an accelerator, wherein the brazing material of the lid is melted, the pair of partition walls and the lid are brazed and integrated.