JPH09204994A - Vacuum chamber with built-in pump for particle accelerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the manufacture. SOLUTION: A vacuum chamber body 29 has a simple cylindrical form having a single cavity part 28 in the inner part, a bulkhead forming part 34 is formed on one side of a base plate 31 for supporting a NEG(non-evaporable getter) pump 42 is formed in the vacuum chamber 29, a cavity part 28 is partitioned into an electron beam passage 32 and a pump chamber 33 by the bulkhead forming part 34, whereby the manufacturing process is simplified, so that the manufacturing cost can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum chamber with a built-in pump for a particle accelerator, which is applied to a particle accelerator such as a recirculation device, a synchrotron or an electron storage ring.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a recirculation apparatus. In the figure, 1 is a linear accelerator, and the linear accelerator 1 includes an electron generator 2 for ejecting electrons (charged particles). A straight tubular acceleration duct 3 having one end connected to the electron generator 2 and an accelerator 4 for accelerating electrons moving inside the acceleration duct 3 by a high frequency current.

A curved end of the deflection duct 5 is connected to the other end of the acceleration duct 3, and the curved portion of the deflection duct 5 has a deflection electromagnet 6 for bending the trajectory of electrons moving therein. Is provided.

Reference numeral 7 is an endless duct for circulating electrons. The endless duct 7 is constructed to have a required length by connecting a plurality of vacuum chambers 8 each having a cross section as shown in FIG. .

At the curved portion of the endless duct 7, a bending electromagnet 9 for bending the orbit of electrons moving inside the endless duct 7 is formed.
An accelerating device 10 for accelerating the electrons circulating inside the endless duct 7 by a high-frequency current is provided at a predetermined straight pipe portion of the endless duct 7.

The other end of the deflection duct 5 is connected to a required portion of the endless duct 7.

Further, one end of an emission duct 11 for guiding electrons from the endless duct 7 to the outside is connected to the curved portion of the required portion of the endless duct 7.

In the recirculation apparatus shown in FIG. 2, after the interior of the acceleration duct 3, the deflection duct 5, the endless duct 7 and the emission duct 11 is evacuated, electrons are emitted from the electron generator 2. The electrons are accelerated by the accelerating device 4 of the accelerating duct 3, and the trajectory is bent by the deflecting electromagnet 6 of the deflecting duct 5, so that the electrons are incident on the endless duct 7.

The electrons that have entered the endless duct 7 circulate in the endless duct 7 by being bent by the deflection electromagnet 9 at the bent portion of the endless duct 7.
Also, each time it goes around the endless duct 7, it is accelerated by the accelerator 10 to become high energy, and the discharge duct 1
It is taken out from 1.

As shown in FIG. 3, the vacuum chamber 8 includes an electron beam passage 12 extending in the longitudinal direction and a pump chamber 13 inside the partition wall 14 with a partition wall 14 therebetween.
An exhaust small hole 15 is formed at 4 to communicate the two.

As shown in FIG. 4, a plate locking groove 16 extending in the longitudinal direction is formed in the pump chamber 13, and the plate locking groove 16 is spaced in the longitudinal direction. A plurality of base plates 23 are fitted and locked, and the base plates 23 have insulating materials 17, 18 and bolts 2
A support arm 19 is attached via a 0 and a nut 21, and a ribbon-shaped NE is attached to the support arm 19.
G Strip 22 (NEG: Non Evaporable Getter)
Is supported.

The NEG strip 22 is formed by pressing powder of zirconium, vanadium, etc. on a thin plate of constantan, and has terminals 24, 25 for connecting to a power source (not shown) attached to both ends in the longitudinal direction. , NEG pump 26.

Then, the electron beam passage 12 of the vacuum chamber 8 and the pump chamber 1 are controlled by a turbo pump (not shown).
After depressurizing the inside of 3, the NEG strip 22 is energized by a power source (not shown) to heat the NEG strip 22 to about 450 degrees Celsius by Joule heat.

Then, the powder of zirconium, vanadium, or the like pressed onto the thin plate of constantan is activated at a high temperature, and the activated powder adsorbs gas molecules, so that the inside of the electron beam passage 12 is in an ultrahigh vacuum state. Becomes

[0015]

However, the conventional vacuum chamber with a built-in pump for a particle accelerator has the following problems.

That is, when the electron beam passes through the inside of the vacuum chamber 8, a current called an image current flows on the wall surface. If the image current is disturbed, the energy of the electron beam is lowered or the trajectory of the electron beam is impaired. The electron beam passage 12 and the pump chamber 13 are separated from each other by the partition wall 14 in order to exert a bad influence such as stabilization.
The electron beam passage 12 is a closed space surrounded by a smooth surface so that the electron beam is not adversely affected.

However, in order to manufacture the vacuum chamber 8 having a complicated shape having the electron beam passage 12 and the pump chamber 13 through the partition wall 14 as described above, a large number of steps are required, so that the manufacturing cost is high. It was expensive.

Since materials such as oxygen-free copper having good vacuum performance are inferior in workability such as formability and weldability to aluminum alloy and stainless steel, the vacuum chamber 8 having the complicated shape is oxygen-free. It was extremely difficult to make with copper.

In view of the above situation, it is an object of the present invention to provide a pump built-in type vacuum chamber for a particle accelerator which can be easily manufactured.

[0020]

According to the present invention, a cylindrical vacuum chamber main body having a single hollow portion inside is provided, and the NEG pump is arranged in the hollow portion toward one side, and at the same time, the NEG pump is provided.
A vacuum chamber with a built-in pump for a particle accelerating device, characterized in that, on one side of a base plate that supports the pump in the main body of the vacuum chamber, a partition forming part that partitions the cavity into an electron beam passage and a pump chamber is formed. is there.

According to the above means, the following effects can be obtained.

The vacuum chamber body is a simple cylinder type having a single cavity inside, and the NEG is housed in the vacuum chamber body.
By forming a partition wall forming part on one side of the base plate for supporting the pump and partitioning the hollow part into the electron beam passage and the pump chamber, the manufacturing process of the vacuum chamber main body is simplified and the manufacturing cost is reduced. In addition to being able to suppress the above, it becomes possible to easily manufacture the vacuum chamber body even from a material having poor workability such as oxygen-free copper.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.

Since the structure of the particle accelerating device such as the recirculation device is the same as that shown in FIG. 2, this drawing will be referred to as necessary.

A cylindrical vacuum chamber body 29 having a single hollow portion 28 therein is formed, and the vacuum chamber body 29 is formed.
A plate locking groove 30 extending in the longitudinal direction is formed on at least one (upper side in the figure) of the upper surface or the lower surface on one side (right side in the figure) of the cavity portion 28 in the left-right direction in the figure.

A single base plate 31 extending in the longitudinal direction is fitted and locked in the plate locking groove 30, and
A cavity 28 is formed on the side portion (left side in the figure) of the base plate 31 so as to extend in the vertical direction, and the cavity portion 28 is provided with the electron beam passage 32 and the pump chamber 3.
The partition forming portion 34 for partitioning into 3 is integrally formed, and the partition forming portion 3
4, an exhaust small hole 35 is formed to connect the both.

Then, the insulating materials 36 and 37 and the bolt 3 are provided at several positions in the longitudinal direction of the base plate 31.
8, a plurality of support arms 40 are attached via nuts 39, and ribbon-shaped NEG strips 41 (NEG: Non Ev) extending in the longitudinal direction are attached to the support arms 40.
aporable Getter) to the base plate 31 so as to be insulated.

The NEG strip 41 is formed by pressing powder of zirconium, vanadium or the like onto a thin plate of constantan, and both ends thereof are connected to a power source (not shown) to form the NEG pump 42.

Reference numeral 43 is a locking claw for locking the upper end of the partition wall forming portion 34 provided on the upper surface of the cavity 28,
The locking claw 43 and the plate locking groove root portion 44 on the electron beam passage 32 side are provided with a concave surface processing (concave surface processing portion 45) for preventing a corner portion from being formed inside the electron beam passage 32. is there.

Next, the operation will be described.

The process of accelerating the electron beam to increase the energy is the same as in FIG. 2 and its explanation is omitted.

After depressurizing the electron beam passage 32 and the pump chamber 33 of the vacuum chamber body 29 by a turbo pump (not shown) or the like, the NEG is powered by a power source (not shown).
The strip 41 is energized to heat the NEG strip 41 to about 450 degrees Celsius by Joule heat.

Then, the powder of zirconium, vanadium, or the like, which is pressure-bonded to the thin plate of constantan, is activated by high temperature, and the activated powder adsorbs gas molecules, so that the inside of the electron beam passage 32 is in an ultrahigh vacuum state. Becomes

When the electron beam passes through the inside of the vacuum chamber main body 29, a current called an image current flows on the wall surface. If the image current is disturbed, the energy of the electron beam is lowered or the trajectory of the electron beam is changed. Since the electron beam passage 32 and the pump chamber 33 are separated by a partition wall so as to have an adverse effect such as instability, the electron beam passage 32 becomes a closed space surrounded by a smooth surface, which adversely affects the electron beam. Must be prevented.

However, in order to manufacture a vacuum chamber main body 29 having a complicated shape having the electron beam passage 32 and the pump chamber 33 via such a partition wall, a large number of steps are required, and the manufacturing cost is high. Will end up.

Further, since materials such as oxygen-free copper having good vacuum performance are inferior in workability such as formability and weldability to aluminum alloy, stainless steel, etc., the above-mentioned complicated vacuum chamber body 29 can be omitted. Very difficult to make with oxygen copper.

Therefore, in the present invention, the vacuum chamber body 2
Reference numeral 9 is a simple tubular shape having a single hollow portion 28 therein, and a partition wall forming portion extending vertically is provided on one side portion of a base plate 31 for supporting the NEG pump 42 in the vacuum chamber main body 29. 34 is integrally formed, and the cavity 28 is partitioned by the partition wall forming portion 34 into the electron beam passage 32 and the pump chamber 33.

As a result, the manufacturing process of the vacuum chamber main body 29 is simplified, the manufacturing cost can be suppressed, and the vacuum chamber main body 29 can be easily manufactured even from a material with poor workability such as oxygen-free copper. You will be able to.

It should be noted that the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention.

[0041]

As described above, according to the vacuum chamber with a built-in pump for a particle accelerator of the present invention, the excellent effect that it can be easily manufactured at low cost can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an example of an embodiment of the present invention.

FIG. 2 is a schematic plan view of a particle accelerator such as a recirculation device.

FIG. 3 is a sectional view of a conventional vacuum chamber.

4 is a view taken in the direction of arrows IV-IV in FIG. 3;

[Explanation of symbols]

 28 Cavity 29 Vacuum Chamber Main Body 31 Base Plate 32 Electron Beam Passage 33 Pump Chamber 34 Partition Forming Section 42 NEG Pump

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiro Nishino 1 Shin Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Ishi Kawashima Harima Heavy Industries Co., Ltd. Yokohama Engineering Center

Claims (1)

[Claims] 1. A cylindrical vacuum chamber main body having a single hollow portion inside, a NEG pump is disposed near the one side in the hollow portion, and a base plate for supporting the NEG pump in the vacuum chamber main body. A vacuum chamber with a built-in pump for a particle accelerating device, characterized in that a partition wall forming part is formed on one side to partition the cavity into an electron beam passage and a pump chamber.