JP2694665B2 - Beam accelerator built-in pump for particle accelerator - Google Patents

Description

The present invention relates to a particle accelerator that forms a high vacuum space for accelerating charged particles, and relates to a particle accelerator that is housed in a beam duct and evacuates. Beam duct built-in pump.

[Conventional technology]

Regarding the beam duct of the conventional particle accelerator, No. 81-2 (1981) of High Energy Physics Laboratory Report No. 5
As discussed on pages 7-61, it consists of an elongated, annular container with a structure that allows it to maintain an ultrahigh vacuum. In order to control the beam trajectory, the beam duct is surrounded by magnets with 2 poles (deflection), 4 poles, etc. In particular, inside the beam duct of the deflection magnet section,
The radiant light generated by the bremsstrahlung irradiates the inner wall of the beam duct and a large amount of gas is desorbed by photostimulation, so that the pressure is higher than that of other ducts. Therefore,
A built-in ion pump that uses the bipolar magnetic field of the deflection magnet is installed inside the beam duct of the deflection magnet unit. In this way, the residual gas is reduced, the scattering associated with the collision between the charged particles and the residual gas is reduced, and the attenuation of the charged particles is reduced.

As a built-in pump, there is a pump that uses a non-evaporable getter in addition to the ion pump. As a pump with a built-in beam duct using this type of pump, JV S.T. 18 (3), April (1981), p. 1114-
Pp. 1116 (JVST, 18 (3), April (1981) PP1114-111
6).

[Problems to be solved by the invention]

In the conventional technology, the increase in pumping speed in the beam duct of the deflecting section is considered, but when the ion pump is adopted as the built-in pump, it is necessary to accelerate the particles due to the discharge characteristics of the ion pump. There was a problem that the discharge characteristics were deteriorated in such a very high vacuum region, and a large evacuation speed could not be obtained. Some non-evaporable getters have been adopted as built-in pumps, but since the thin plate was used as the base material and was developed in a two-dimensional (flat) shape in the longitudinal direction of the beam duct, the exhaust speed of the non-evaporable getter is Considering that it is proportional to the surface area of, the exhaust speed is limited.
Further, there is a problem that it is difficult to install the device in a place having a curvature such as the deflecting part.

An object of the present invention is to provide a beam duct built-in pump which reduces the pressure inside the beam duct of a particle accelerator to prevent the scattering of charged particles, has high reliability, and is easy to maintain.

[Means for solving the problem]

In order to achieve the above-mentioned object, the beam duct built-in pump of the particle accelerator according to the present invention is provided with a partition wall of a beam duct having a partition wall between an orbit chamber and a pump chamber adjacent to the orbit chamber. Evacuate from the individual exhaust holes and maintain the ultra-high vacuum in the orbit chamber to accelerate charged particles, and in the beam duct built-in pump of the particle accelerator housed in the pump chamber, the substrate to which the getter material is attached becomes bellows-shaped. It is configured to be bent to increase its surface area and to connect at least one non-evaporable getter pump that maintains an ultra-high vacuum by activating the getter material.

Then, a sealing flange provided with a current introduction terminal for supplying a current for activating the non-evaporable getter pump is provided,
A sealing flange is attached to each end face of the pump chamber adjacent to the beam duct, each non-evaporable getter pump is connected via a carriage electrode plate, and the carriage is fixed to the carriage electrode plate, and the carriage and the pump chamber inner wall And an insulating material between the partition and the partition.

Furthermore, at least one bearing is provided on each trolley, each non-evaporable getter pump is made movable in the beam duct, and the current introduction terminal mounted on each sealing flange and the non-evaporable getter pump are connected. An elastic member is provided on at least one side of the connecting portion.

[Action]

According to the present invention, by connecting at least one non-evaporable getter pump having an increased surface area of getter material as a beam duct built-in pump of a particle accelerator, the pump can be easily accommodated in a deflected beam duct having a large curvature. The exhaust velocity lowers the pressure in the beam duct and reduces the attenuation of charged particles circulating in the beam duct.

And when electrically heating the non-evaporable getter pump,
The expandable member is pressed against the inner wall of the pump chamber and the partition wall, and is insulated by the insulating material, eliminating the risk of current short circuit.

〔Example〕

One embodiment of the present invention will be described with reference to FIGS.

As shown in FIGS. 1 to 3, at least one of the partition walls 5 of the beam duct 1 including the partition wall 5 between the orbit chamber 2 and the pump chamber 3 adjacent to the orbit chamber 2 is provided. Exhaust hole 6
From inside the orbit chamber 2 to maintain ultra-high vacuum and charged particles
In the beam duct built-in pump of the particle accelerator that accelerates 11 and is housed in the pump chamber 3, the substrate 30 to which the getter material is attached is bent in a bellows shape to increase its surface area, and activation of the getter material increases the ultrahigh temperature. The configuration is such that at least one non-evaporable getter pump 4 that holds a vacuum is connected.

Then, a sealing flange 9 provided with a current introduction terminal 8 for activating the non-evaporable getter pump 4 shown in FIGS. 7 and 8 is provided, and each of the pump chambers 3 adjacent to the track chamber 2 is provided. A sealing flange 9 is attached to the end face, each non-evaporable getter pump 4 shown in FIGS. 4 to 6 is connected via a carriage electrode plate 25, and the carriage 7 is fixed to the carriage electrode plate 25. An insulating material 15 is provided between the carriage 7 and the inner wall of the pump chamber 3 and the partition wall 5.

Further, each carriage 7 is provided with at least one rolling bearing 12, 13, and 14 to make each non-evaporable getter pump 4 movable within the beam duct 1, as shown in FIGS. 7 and 8. An electrode 10 and a spring 19 bent to at least one side of the connection portion between the current introduction terminal 8 mounted on each sealing flange 9 and the non-evaporable getter pump 4.
The elastic member is composed of

The deflecting magnet magnetic field that deflects the charged particles 11 works in the direction perpendicular to the paper surface. In FIG. 1, the magnet is omitted and not shown. The beam duct 1 is an orbit chamber 2 which is an orbit of charged particles 11 and a modular non-evaporable getter pump 4.
And a pump chamber 3 for storing Orbit room 2
The pump chamber 3 is separated by a partition wall 5 having a shape that keeps the cross-sectional shape of the orbit chamber 2 uniform. A non-evaporable getter pump 4 connected and supported by a carriage 7 in the pump chamber 3.
The non-evaporable getter pumps 4 at both ends
Is electrically connected to the atmosphere side through a feedthrough (current introducing terminal) 8 attached to a sealing flange 9 by an electrode 10. FIG. 2 shows an embodiment in which the partition wall 5 is viewed from the side of the orbit chamber 2. The partition wall 5 is provided with at least one exhaust hole 6 for exhausting gas from the orbit chamber 2. FIG. 3 shows an embodiment of a non-evaporable getter pump. This non-evaporable getter pump heats the base material (substrate) with a getter material such as Ti or Zr adhered to the surface by heating the getter material to release adsorbed gas (H ₂ , CO, etc.) or to the inside. It is activated by diffusion to facilitate adsorption of gas molecules, and vacuum exhaust is performed.

Next, the operation of this embodiment will be described with reference to FIGS.

The beam duct 1 of the particle accelerator prevents the charged particles 11 from colliding with the residual gas in the beam duct 1 and scattering,
Ultra high vacuum (10 ^-8 to 10 ^-11 Torr) must be maintained to prevent loss of ¹¹ . Therefore, the beam duct 1 has exhaust ports (not shown) provided on one or more beam ducts 1.
Via an auxiliary pump such as a turbo-molecular pump. In order to achieve an ultra-high vacuum, the beam duct 1 is heated and degassed thereafter, and a current is passed between the feedthroughs 8 while the auxiliary pump is exhausting to activate the non-evaporable getter pump 4. The non-evaporable getter pump 4 is activated by electric heating,
Works as a vacuum pump. The gas released from the getter material during electric heating is exhausted by the auxiliary pump. The activated non-evaporable getter pump 4 exhausts the residual gas in the orbit chamber 2 through the exhaust hole 6 provided in the partition wall 5 shown in FIG. Under ultra-high vacuum, the gas released from, for example, the wall surface of the stainless steel container is the main gas source, so the non-evaporable getter pump 4 can also exhaust the gas released from the inner wall of the pump chamber 3. When the charged particles 11 are deflected by a deflection magnetic field or the like, electromagnetic waves called orbital radiation are emitted in the tangential direction of motion. Especially when the charged particles 11 are light,
That is, in the case of an electron or a positron, it becomes a strong electromagnetic wave and many photons irradiate the inner wall of the beam duct 1 and emit gas from the wall surface of the container by photostimulation, which has a great adverse effect on the acceleration or accumulation of the charged particles 11. . However, the pressure in the orbit chamber 2 can be sufficiently lowered by providing the pump chamber 3 near the gas generation source and evacuating the generated gas as in the present embodiment, and the loss of the charged particles 11 can be significantly reduced. Can be reduced to Further, since the surface area of the getter material is increased and the non-evaporable getter pump having a large exhaust speed is connected and housed inside the pump chamber 3, the exhaust speed can be further increased, and the charged particles 11 in the orbit chamber 2 can be increased. The scattering and disappearance of can be further reduced significantly.

4 to 6 show an embodiment relating to the connecting portion of the non-evaporable getter pump. The embodiment shown in FIG. 4 shows a carriage 7 for connecting a non-evaporable getter pump 4 housed in a pump chamber 3. Non-evaporable getter pump 4 is bolt 24
Are connected to the carriage electrode plate 25 by means of and are connected to the carriage 7 by bolts 23. Rolling bearings 12, 13 and 14 are attached to the carriage 7. FIG. 5 shows the inside of the pump chamber 3 when the pump chamber 3 is viewed from the side, and the carriage 7 is roughly divided into two parts. One is a carriage electrode plate 25 connected to the non-evaporable getter pump 4, and the other is a carriage traveling portion 26. The truck electrode plate 25 and the truck running portion 26 are fixed with bolts 23 via the insulating material 15. FIG. 6 is a partial sectional view of the carriage 7. As described above, the carriage 15 is insulated from the carriage electrode plate 25 and the carriage running portion 26 by the insulating material 15. Since the carriage running portion 26 travels in the pump chamber 3, the rolling bearing 13 runs on the inner peripheral side of the pump chamber 3 by using the outer peripheral surface of the rolling bearing, and the outer peripheral edge portion of the rolling bearing on the outer peripheral side of the pump chamber 3. The rolling bearing 14 is mounted diagonally with respect to the bottom surface of the pump chamber 3 while traveling. Further, a rolling bearing 12 is mounted which runs on the inner peripheral side surface of the pump chamber 3.

According to the present embodiment, the non-evaporable getter pumps 4 that are adjacent to each other through the carriage electrode plate 25 can be fixed according to the cross-sectional shape of the pump chamber 3, and the energization for activation can be performed. Further, even if electricity is applied, the carriage running portion 26 and the carriage electrode plate 25 are electrically insulated by the insulating material 15, so there is no risk of short circuit. Rolling bearing 13 mounted on the carriage running part 26
And 14 make the pump chamber 3 of the non-evaporable getter pump 4
It can be easily inserted into and pulled out for maintenance. By rolling only the outer peripheral side rolling bearing 14 at the edge portion as in the present embodiment, it is possible to smoothly move the non-evaporable getter pump connected even in the pump chamber having a curvature like the deflection portion. . In this embodiment, the non-evaporable getter pump is connected by the trolley electrode plate, but when the curvature of the pump chamber in the longitudinal direction changes, the connection between the trolley electrode plate and the non-evaporable getter pump has a hinge structure. It is sufficient to give the connecting portion a degree of freedom. In that case, since an electric current is passed, it is possible to energize by providing a separate electrode between the non-evaporable getter pumps. Further, in this embodiment, an insulating material is interposed between the carriage electrode plate and the carriage running portion for insulation between the beam duct and the non-evaporable getter pump, but all rolling bearings are used without using the insulating material. May be made of ceramics.

Further, instead of the rolling bearing, a slide bearing or the like can be used instead.

FIG. 7 shows an embodiment of an electrode for connecting the feedthrough 8 attached to the sealing flange 9 and the non-evaporable getter pump 4 at the end. An electrode 10 having a multi-layered electrode thin plate made of copper or the like and partially bent is connected between the non-evaporable getter pump 4 and the feedthrough 8. The insulating material 27 is fixed by bolts 31 that connect the electrode 10 and the non-evaporable getter pump 4. The insulating material 27 fixes the plate supporting base 20, and the plate supporting base 20 is connected to the spring 19 connected to the hook 29 provided on the sealing flange 9 via the hook 28 and is further bent to have a spring characteristic. A plate support plate 18 that supports an insulating plate plate 17 installed so as to surround the four sides of the electrode 10 is fixed. FIG. 8 shows an embodiment of the sealing flange 9 and the feedthrough 21. The electrode 10 shown in FIG. 7 is connected to the connection portion 16 on the vacuum V side. The feedthrough 8 is fixed to a flange 21 having a smaller diameter than the sealing flange 9 via an insulating material such as ceramics. The flange 21 connected to the electrode 10 is attached from the vacuum V side of the sealing flange 9,
It is fixed and sealed by bolts 22. At this time, the hook 29 is configured to pull the entire non-evaporable getter pump connected by the spring 19 shown in FIG. The sealing flange 9 is fixedly sealed to a flange (not shown) provided at the end of the pump chamber 3. Although FIG. 7 shows only the plate support 20 and the carriage is omitted, in order to support the non-evaporable getter pump and the self-weight of the electrode, a carriage equivalent to the carriage 7 shown in FIGS. 4 to 6 is used. It is attached to the plate support 20. FIG. 9 is an embodiment showing an electrode on the side opposite to FIG. The structure is almost the same as that of FIG. 7, but a stopper 23 is used instead of the spring 19.

According to this embodiment, the non-evaporable getter pump inserted in the pump chamber 3 has the stopper and the electrode shown in FIG. 9 attached to the sealing flange to fix the sealing flange, and then the other spring. By adjusting the length of the electrode 10 and the spring 19 shown in FIG. 7 in advance so that a tensile force acts on both the electrodes 10 and the spring 19 shown in FIG. The evaporative getter pump is pressed against the inner wall of the pump chamber via the slide shaft, and the position inside the pump chamber is not fixed after fixing the sealing flange, and the non-evaporable getter pump body contacts the inner wall of the pump chamber to activate the call. It is possible to prevent the occurrence of accidents due to short circuits. Further, when the energization is activated, the non-evaporable getter pump reaches a high temperature of several hundreds of degrees, and the connected non-evaporable getter pump expands and contracts in the longitudinal direction. Can be absorbed by Further, since the non-evaporable getter pump is pressed against the inner peripheral wall of the pump chamber due to the pulling force of the spring, there is no risk of short circuit. Even if the plate-spring-shaped electrode bent due to heat strain or the like is distorted toward the inner wall of the pump chamber, the insulating plate plates installed so as to surround the electrode from all sides prevent a short circuit.

〔The invention's effect〕

According to the beam duct built-in pump of the particle accelerator of the present invention, since the non-evaporable getter pump in which the substrate to which the non-evaporable getter is attached is bent and attached can be stored over a plurality of units, the exhaust speed can be dramatically increased, The pressure in the beam duct can be significantly reduced, the scattering and disappearance of the charged particles can be greatly reduced, and the life of the charged particles can be significantly extended. Further, it is possible to prevent the non-evaporable getter pump and the electrode exposed during the electric heating from contacting the inner wall of the beam duct, and it is possible to eliminate a short circuit accident. Further, there is an effect that it is very easy to put the connected non-evaporable getter pump in and out of the beam duct, and the assembling and maintenance are easy.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a beam duct which is an embodiment of the present invention, FIG. 2 is a front view of a partition wall seen from the orbit chamber shown in FIG. 1, and FIG. 3 is an example of a non-evaporable getter pump. The plan view shown in FIG. 4 is a plan view showing an embodiment of the carriage connecting portion, and FIG.
The figure is a vertical cross-sectional view as seen from the inner circumference side of the pump chamber in Fig. 4, Fig. 6 is a cross-sectional view taken along the line VI-VI of Fig. 5, and Fig. 7 is an expansion and contraction connecting the feedthrough and the non-evaporable getter pump. FIG. 8 is a vertical sectional view showing an example of a member, FIG. 8 is a partial sectional view showing an example of a sealing flange, and FIG. 9 is a vertical section showing an example of the other side of the connecting portion shown in FIG. It is a figure. 1 ... Beam duct, 2 ... Orbit room, 3 ... Pump room,
4 ... Non-evaporable getter pump, 5 ... Partition, 7 ... Cart, 8 ... Feedthrough (current introducing terminal), 9 ... Sealing flange, 10 ... Electrode, 11 ... Charged particle, 12, 13,14 ...
… Rolling bearings, 15 …… Insulation material, 19 …… Springs (expansion / contraction members), 25 …… Bogie electrode plates.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mamoru Katane 3-1-1, Saiwaicho, Hitachi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor Shinjiro Ueda, 502 Jinmachi, Tsuchiura, Ibaraki Hitachi Ltd. Mechanical Research Laboratory (72) Inventor Manabu Matsumoto 502 Jinmachicho, Tsuchiura City, Ibaraki Prefecture Hitachi Mechanical Laboratory Co., Ltd. (72) Takashi Ikeguchi 502 Jinmachicho, Tsuchiura City, Ibaraki Prefecture Hitachi Mechanical Research Co., Ltd. In-house (72) Inventor Shunji Kakiuchi 3-1-1 Hitachi-machi, Hitachi City, Ibaraki Hitachi Ltd. (72) Inventor Toa Hayasaka 3-1 Morinosato Wakamiya, Atsugi City, Kanagawa Prefecture NTT LSI Laboratories, Nippon Telegraph and Telephone Corporation (72) Inventor Toyoki Kitayama 3-1 Morinosato Wakamiya, Atsugi City, Kanagawa Prefecture Nippon Telegraph and Telephone Corporation TTLSI the laboratory (56) References Patent Sho 63-198300 (JP, A) JP Akira 64-27200 (JP, A) JP Akira 53-57516 (JP, A)

Claims (3)

(57) [Claims] 1. An exhaust gas is exhausted from at least one exhaust hole provided in the partition of a beam duct having a partition between the orbit chamber and a pump chamber adjacent to the orbit chamber, and the inside of the orbit chamber is super-high. In a beam duct built-in pump of a particle accelerator that is held in a vacuum to accelerate charged particles and is housed in the pump chamber, a substrate to which a getter material is attached is bent in a bellows shape to increase its surface area. At least one non-evaporable getter pump that holds the ultra-high vacuum is connected by activation of each, and each non-evaporable getter pump is connected through a carriage electrode plate, and the carriage is fixed to the carriage electrode plate. In addition, a beam duct built-in pump for a particle accelerator, characterized in that an insulating material is provided between the carriage and the inner wall of the pump and the partition wall. 2. A non-evaporable getter pump is provided with a sealing flange to which a current introducing terminal for activating current is provided, and the sealing flange is attached to each end face of the pump chamber adjacent to the beam duct. An evaporation type getter pump is connected via a carriage electrode plate, the carriage is fixed to the carriage electrode plate, and an insulating material is provided between the carriage and the pump chamber inner wall and partition wall. Beam duct built-in pump. 3. The beam of a particle accelerator according to claim 1, wherein each carriage receives at least one bearing, and each non-evaporable getter pump is movable in the beam duct. Duct built-in pump.