JPH0779040B2 - Superconducting ultra-compact SOR ring device - Google Patents

Description

The present invention relates to a superconducting microminiature SOR ring device used as a radiation source for lithography, for example.

[Prior Art] Fig. 3 shows, for example, the technical report "Su
perconducting Racetrack Electron Storage Ring and
Coexistent Injector Microtron for Synchrotron Radi
ation "ISSN 0082-4798 Ser.B No.21 Septenber 1984 is a plan view of a conventional superconducting ultra-compact SOR ring, in which (1) is an electron beam incident part, and (2)
Is a race-track type vacuum chamber for rotating the electron beam incident from the incident part (1) at a high speed,
(3) is a superconducting bending electromagnet arranged in a curved portion of the vacuum chamber (2), (4) is a quadrupole electromagnet arranged in a straight portion of the vacuum chamber (2), (5) is a high frequency acceleration cavity, (6)
Is a skew cue electromagnet, and (7) is a 6-pole electromagnet.

The superconducting ultra-compact SOR ring device with a circumference of 10 m or less is a device that stores high-speed electrons accelerated by a linear accelerator or electron synchrotron for a long time, and the electron beam (load particles) incident from the injection part (1) is a vacuum chamber. (2) Rotate the inside at high speed. The superconducting deflection electromagnet (3) functions to bend the electron beam. The superconducting deflection electromagnet (3)
Only by itself, the trajectory of the electron beam has an arc shape in the racetrack-shaped superconducting bending magnet, and apart from the linear design trajectory in other parts, it immediately falls into the vacuum chamber (2) and disappears. Therefore, a quadrupole electromagnet (4) that functions to focus the electron beam on the designed orbit is required. The 6-pole electromagnet (7) has a function of correcting aberrations of electron beams having different energies, and has a high-frequency acceleration cavity (5).
Is a device that serves to supply more energy to the reduced energy electron beam. The skew cue electromagnet (6) is an electromagnet that functions to adjust the shape of the mass of the electron beam circulating in the vacuum chamber (2).

The conventional superconducting microminiature SOR ring device is theoretically established by arranging the above components on the design orbit.

[Problems to be Solved by the Invention] As described above, in the conventional superconducting microminiature SOR ring device,
For example, the quadrupole electromagnet (4) is installed on the design orbit even though the orbit (hereinafter referred to as the equilibrium orbit) through which the actual electron beam passes is not on the design orbit due to the influence of the leakage magnetic field of the superconducting deflection electromagnet (3). ing. Therefore, the quadrupole electromagnet (4) has a function of deflecting the electron beam in addition to the function of focusing the original electron beam.

As a result, the orbit is further deviated, and the orbit is deviated to the region where the magnetic field is not uniform, which makes it difficult to stably rotate the electron beam. This is because the conventional design is based on the same theory as a large accelerator.

The present invention has been made to solve the above problems, and an object thereof is to obtain a superconducting microminiature SOR ring device in which a quadrupole electromagnet only functions to focus an electron beam.

[Means for Solving the Problems] In the superconducting ultra-compact SOR ring device according to the present invention, the quadrupole electromagnet is displaced from the design trajectory of the straight portion of the vacuum chamber and is arranged so as to match the equilibrium trajectory of the electron beam. .

[Operation] In the superconducting microminiature SOR ring device according to the present invention, the center of the quadrupole electromagnet is displaced from the design orbit, that is,
By placing the quadrupole electromagnet on the equilibrium orbit greatly deviated from the design orbit due to the action of the non-uniform magnetic field distribution of the superconducting bending electromagnet, the quadrupole electromagnet acts only to focus the electron beam. .

[Examples] Examples of the present invention will be described below. FIG. 1 is a schematic plan view of an embodiment of the present invention, in which the same or corresponding parts as those in FIG. 3 described above are designated by the same reference numerals and the description thereof is omitted.

In the figure, (8) is a design track of an electron beam designed in a race track shape, and (9) is a superconducting deflection electromagnet (3).
2 shows an equilibrium orbit of an electron beam that is largely deviated from the design orbit due to the action of the non-uniform magnetic field distribution of. Therefore, in the present invention, the center of the quadrupole electromagnet (4) is arranged on the balanced orbit (9).

In the above structure, the high-speed electron beam is incident on the incident part (1).
When incident from above, the superconducting deflection electromagnet (3), the quadrupole electromagnet (4), the skew cue electromagnet (6), and the sextupole electromagnet (7) are operated by the electromagnets to move through the racetrack type vacuum chamber (2). The beam will rotate.
At that time, the superconducting deflection electromagnet (3) is a magnet that functions to deflect the electron beam, and since this magnet is a superconducting magnet, the magnetic field distribution is not rectangular but the deflection trajectory (9).
Deviates greatly from the design trajectory (8).

Fig. 2 shows the equilibrium orbit (9) in the superconducting bending magnet (3).
It is a figure showing the deviation from the design trajectory (8) of. As can be seen from FIG. 2, the equilibrium orbit (9) of electrons is about 8 mm from the design orbit (8) at the exit of the superconducting bending electromagnet (3).
You can see that it is shifted to the outside. This is a superconducting ultra-small SO
This is a very large amount for the R ring. In the conventional accelerator design, since there was no simulation program for the ultra-small SOR ring, the design theory of the large accelerator was applied as it was, and this deviation was ignored. Therefore, the linear portion of the vacuum chamber (2) was ignored. However, although the equilibrium orbit (9) is largely deviated to the outside or the inside from the design orbit (8), the quadrupole electromagnet is arranged on the design orbit (8). However, in the present invention, the deviation of the equilibrium orbit (9) is calculated by a simulation program, and the quadrupole electromagnet (4) is arranged on the equilibrium orbit (9),
As a result, the quadrupole electromagnet only serves to focus the electron beam on the equilibrium orbit (9).

Although only the superconducting microminiature SOR ring device in which the quadrupole electromagnet (4) is deviated from the design trajectory (8) is referred to in the above-mentioned embodiment, other components constituting the superconducting microminiature SOR ring are designed in the same manner. It is also necessary to displace the orbit (8) on the equilibrium orbit (9) in order to stably rotate the electron beam.

[Effects of the Invention] As described above, according to the superconducting microminiature SOR ring device of the present invention, since the quadrupole electromagnet is arranged on the equilibrium orbit so as to be displaced from the design orbit, the quadrupole electromagnet generates the original electron beam. There is an effect that only the function of focusing is performed, and the electron beam can be stably rotated without being deflected by the quadrupole electromagnet.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an embodiment of the present invention, FIG. 2 is an explanatory view showing that the equilibrium orbit in the superconducting bending electromagnet is out of the designed orbit, and FIG. 3 is a conventional superconducting microminiature. It is a top view of a SOR ring device. In the figure, (1) is an incident part, (2) is a vacuum chamber, (3) is a superconducting deflection electromagnet, (4) is a quadrupole electromagnet,
(8) is a design trajectory, and (9) is an equilibrium trajectory. In each drawing, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A racetrack-shaped vacuum chamber, a superconducting deflection electromagnet that is arranged in a curved portion of the vacuum chamber and deflects an electron beam, and a linear portion of the vacuum chamber that focuses the electron beam. In a superconducting ultra-compact SOR ring device including a 4-pole electromagnet,
A superconducting ultra-compact SOR characterized by arranging polar electromagnets on the equilibrium orbit of an electron beam deviating from the design orbit
Ring device.