JPH06222150A - Screen monitor of particle accelerator - Google Patents

Abstract

PURPOSE:To permit an application point of high-energy radiation to be heated to a red-hot state without melting so as to clearly monitor the position of the radiation through observation of the red-hot position, to adjust the degree of red heat of the application point by rotating the screen, to prevent overheating of a frame and a screen by using a water-cooled frame, to adjust the degree of red heat of the application point by regulating cooling capacity, and to prevent heat damage to the frame by forming the front side of the frame into an inclined face. CONSTITUTION:A screen 20 is provided in such a manner as capable of going inside and out of the beam line of a particle accelerator. A panel molded from a material with a high melting point, such as carbon or tungsten, is used as the screen so that an application point of radiation is heated to a red-hot state. The screen is rotated and tilted relative to the optical axis of radiation and is mounted on a water-cooled frame 23, and the front side of the frame is preferably formed into an inclined face 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen monitor provided on a beam line of a particle accelerator such as a synchrotron.

[0002]

2. Description of the Related Art In recent years, a synchrotron is being developed as a relatively small particle accelerator having a diameter of 10 m or less,
Utilizing synchrotron radiation (SOR light), which is radiation emitted from such a synchrotron, for example, manufacturing of VLSI, diagnosis in the medical field, molecular analysis,
It is expected to be applied to various fields such as structural analysis.

FIG. 4 shows an outline of a small synchrotron. An electron beam generated by an electron generator 1 such as an electron gun is accelerated by a linear accelerator (linac) 2 to near the speed of light, and a deflecting electromagnet 3 is used. It is deflected and enters the storage ring 5 via the inflector 4. The electron beam incident on the storage ring 5 is converged by the converging electromagnet 7 while being given energy by the high-frequency accelerating cavity 6, is deflected by the deflection electromagnet 8, and continues to orbit the storage ring 5. Then, the SOR light S is generated when being deflected by the deflection electromagnet 8, and the SOR light S is emitted to, for example, the exposure device 10 through the beam line 9 which is a light extraction line for use.

In the particle accelerator as described above, SO
It is necessary to monitor whether or not the R light S passes through a predetermined orbit in the beam line 9 at the beginning of the operation, and a screen monitor for that purpose is installed at an important point of the beam line 9.

FIG. 5 shows an example of a screen monitor that is generally used in the past. This is a screen 15 which is inclined by a predetermined angle with respect to the beam line
Is provided to be movable up and down (movable in the front and back direction of the paper in FIG. 5) to enter and leave the beam line 9, and a camera 16 is provided on the side of the screen 15 toward the screen 15 side. belongs to. As the screen 15, it is general that the surface of a substrate such as glass is coated with a fluorescent substance and scales, for example, as shown in FIG.

With the above screen monitor, SOR light S
When the optical axis of the screen 15 is monitored, the screen 15 is lowered and placed in the beam line 9 as shown in FIG. 5, and then the SOR light S is applied to the surface of the screen 15 from the upstream side of the beam line 9. And irradiate. Then, since the position irradiated with the SOR light S emits fluorescence and shines, the actual optical axis of the SOR light S is confirmed by observing the position with the camera 16 through the viewport 17, and if necessary, based on it. Then, the optical axis is corrected. After such work is completed, the screen 15 is pulled up to exit the beam line 9 and the normal operation is started.

[0007]

By the way, when the screen 15 as described above is irradiated with the SOR light S, its irradiation point is heated by the heat energy of the SOR light S. Since the energy of SOR light is not so large in the small synchrotron as shown in FIG. 4, there is no problem in using the screen 15 in which the fluorescent material is applied to the substrate as described above. However, when such a screen 15 is applied as it is to a large particle accelerator in which the energy of SOR light is extremely large, the temperature of the irradiation point may exceed the melting point of the substrate, and the screen 15 may melt locally. is there.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a screen monitor having excellent heat resistance and applicable to a large particle accelerator.

[0009]

According to the present invention, in order to monitor the radiant light extracted through the beam line of a particle accelerator, a screen monitor in which a screen irradiated with the radiant light is provided so as to enter and leave the beam line. The screen is formed of a molded plate made of a high melting point material such as carbon or tungsten which is red-heated when irradiated with radiant light and heats red. In this case, it is preferable that the screen can be rotated in the beam line so as to be inclined with respect to the optical axis of the emitted light, and the screen is attached to the frame of the water cooling structure, and the emitted light of the frame is irradiated. It is preferable that the surface on the side facing the optical axis is an inclined surface inclined with respect to the optical axis of the emitted light.

[0010]

In the screen monitor of the present invention, a molded plate made of a high melting point material such as carbon or tungsten having a melting point of 3,000 ° C. or higher is used as the material of the screen, and the screen is irradiated with radiant light. When it is done, the irradiation point does not melt and heats up and becomes red, so
The position of the radiated light is monitored by observing the red-hot position. At this time, if the screen is rotated and tilted with respect to the optical axis of the radiated light, the irradiation area of the radiated light changes, the amount of heat input to the screen changes, and the degree of red heat can be adjusted. Further, by mounting the screen on the frame of the water cooling structure, it is possible to prevent the frame itself and the screen from being overheated, and by adjusting the cooling capacity, the temperature of the screen and hence the degree of red heat can be adjusted. Further, by arranging the front side of the frame as an inclined surface, the irradiation area of the radiated light on the frame is expanded, the heat load is naturally reduced, and heat damage to the frame is prevented.

[0011]

Embodiments of the present invention will be described below with reference to FIGS. In the screen monitor of this embodiment, as shown in FIG. 3, the screen 20 is arranged in the beam line 9 to irradiate the SOR light S, and the irradiation position is obliquely forward through the viewport 22 by the camera 21 provided outside. The SOR light is monitored by observing from above.

The screen 20 in this embodiment is made of a material having a very high melting point, such as carbon (having a melting point of 3,7).
This screen 2 is made of a molded plate made of, for example, 00 ° C) or tungsten (3,410 ° C).
It is said that 0 does not melt even if the high energy SOR light S is irradiated, because the irradiation point generates heat and only red heat is generated.

The screen 20 described above is shown in FIGS.
It is attached to the rectangular frame 23 as shown in
A shaft body 24 penetrating the beam line 9 is connected to an upper portion of the frame 23. The shaft 24 is in the longitudinal direction (vertical direction) of itself by an appropriate drive mechanism (not shown).
The shaft 20 is moved up and down and rotated about its own axis. By moving the shaft 24 up and down, the screen 20 together with the frame 23 is moved in and out of the beam line 9, and the shaft 24 is rotated. The direction of the screen 20 can be changed to tilt the screen 20 with respect to the optical axis of the SOR light S.

The frame 23 is made of a heat-resistant metal such as copper and has a water cooling structure having a cooling water passage 25 as shown in FIG. 2, forcibly circulating the cooling water. This cools the frame 23 and the screen 20 to prevent them from overheating. Further, the front surface side of the frame 23, that is, the surface on the side irradiated with the SOR light S is an inclined surface 26 that is inclined with respect to the optical axis of the SOR light S. The inclination angle θ of the inclined surfaces 26 with respect to the optical axis may be set to about 10 °.

In the screen monitor having the above structure, since the screen 20 is made of a high melting point material such as carbon or tungsten, it does not melt even when irradiated with high energy SOR light S. Since the irradiation point glows red and emits light, the observation by the camera 21 can be performed clearly.

Usually, as shown in FIG. 3A, the screen 20 is preferably arranged in a state of being orthogonal to the optical axis of the SOR light S, but if necessary, for example S.
When the irradiation point does not reach a high temperature and does not reach the red hot temperature due to the low intensity of the OR light S, the shaft 24 is rotated to rotate the screen 20 as shown in FIG. 3B.
May be inclined with respect to the optical axis of the SOR light S. By doing so, the irradiation area of the SOR light S on the screen 20 is expanded, and thereby the heat input amount to the screen 20 is increased (in other words, the transmission amount is decreased), and the temperature of the irradiation point is increased, It becomes easy to glow red. Further, when the irradiation point does not glow sufficiently red, the temperature of the frame 23 and the screen 20 is also increased by reducing the cooling capacity by adjusting the amount and temperature of the cooling water circulated and supplied to the frame 23. It is possible to make the irradiation point red hot.

Further, in the above screen monitor, since the front surface side of the frame 23 is the inclined surface 26, heat damage to the frame 23 can be effectively prevented. That is, when the screen 20 is moved up and down, it is inevitable that the SOR light S irradiates the frame 23 for a very short time. Therefore, when the SOR light S has high energy, the frame 23 is localized. There is concern that it will melt into. Therefore, in the above screen monitor, not only the frame 23 is forcibly water-cooled by the water cooling structure, but also the front surface side of the frame 23 is formed as the inclined surface 26 so that the irradiation area of the SOR light S with respect to the frame 23 is naturally expanded. As a result, the heat load per unit area is reduced, and the overheating of the frame 23 is suppressed. If the screen 20 is tilted as shown in FIG. 3B when the screen 20 is moved up and down, the irradiation area of the SOR light S on the frame 23 is expanded not only in the vertical direction but also in the horizontal direction. Therefore, it is preferable to tilt the screen 20 in such a manner at least when moving it up and down.

[0018]

As described above, according to the present invention, since the molding plate made of a high melting point material such as carbon or tungsten is adopted as the material of the screen, the screen can be irradiated with high energy radiation. In addition to having excellent heat resistance that does not melt, the irradiation point of radiant light glows red light and emits light, so it has the effect that it can be observed clearly, especially for large particle accelerators. It is suitable to apply. Further, by configuring the screen to rotate, it is possible to adjust the irradiation point to the red hot temperature by inclining the direction of the screen with respect to the optical axis of the emitted light, if necessary. By attaching the screen to the frame of water cooling structure, the frame itself and the screen can be cooled and their overheating can be prevented, and the degree of red heat at the irradiation point can be adjusted by adjusting the cooling capacity. By making the front side an inclined surface, it is possible to effectively prevent thermal damage to the frame.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of a screen monitor that is an embodiment of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a plan view showing a usage state of the apparatus.

FIG. 4 is a plan view showing an outline of a small synchrotron.

FIG. 5 is a plan view showing a usage state of a conventional general screen monitor.

FIG. 6 is a front view of a screen of the monitor.

[Explanation of symbols]

 S SOR light (synchronized light) 9 Beamline 20 Screen 21 Camera 23 Frame 24 Shaft 25 Cooling water flow path 26 Slope.

Claims (3)

[Claims] 1. A screen monitor having a structure in which a screen irradiated with radiant light is provided so as to enter and leave the beam line in order to monitor radiant light extracted through a beam line of a particle accelerator. A screen monitor for a particle accelerator, which is formed of a molded plate made of a high melting point material such as carbon or tungsten that is red-heated when irradiated with radiant light and red heats. 2. The screen monitor for a particle accelerator according to claim 1, wherein the screen is rotatable in a beam line so as to be inclined with respect to an optical axis of the emitted light. 3. The screen is attached to a frame having a water-cooling structure, and a surface of the frame on the side irradiated with radiant light is an inclined surface inclined with respect to the optical axis of the radiated light. The screen monitor of the particle accelerator according to 1 or 2.