JP2952011B2 - Charged particle device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a charged particle device for transporting, accelerating, decelerating, and accumulating a beam of charged particles, for example, electrons and ions.

[Prior art] Conventionally, this type of charged particle device has been described in “Design of UVSOR Storage Ring” published by Institute of Molecular Science, UVSOR-9 (1
December 982).

FIG. 5 is a sectional view showing a conventional quadrupole electromagnet (1), and FIG.
The figure shows a cross-sectional view of the skew electromagnet (2).
(3) is a gantry for supporting them, and (4) is a beam duct through which charged particles pass. FIG. 7 shows an example in which these are incorporated in a part of the storage ring.

Next, the operation will be described. The bundle (beam) of charged particles passing through the inside of the beam duct (4) is a quadrupole electromagnet (1)
By the magnetic field created by the convergence and divergence force in the x and y directions, acting as a lens on the beam optics,
In the storage ring, parameters such as betatron function are determined (the x direction is a direction perpendicular to the beam advancing direction in the beam deflection plane in the storage ring, and the y direction is a direction perpendicular to the beam advancing direction and the x direction). On the other hand, the skew quadrupole electromagnet (2) is constructed such that the quadrupole electromagnet (1) is
相当 It is equivalent to a rotated one and adjusts the degree of coupling in the x- and y-directions in the storage ring etc. by the magnetic field created by the magnetic field, and as a result, controls the ratio of the beam shape in the X-direction and the y-direction. Used to

[Problems to be Solved by the Invention] In the conventional charged particle device as described above, since the quadrupole electromagnet and the skew quadrupole electromagnet are fixed with respect to the beam axis, the size of the beam shape in the x and y directions is large. In order to control the height ratio, it is necessary to use a skew quadrupole electromagnet in addition to the quadrupole electromagnet, which not only increases the number of electromagnets and the necessary power supplies, but also makes the spatial arrangement in the beam orbit direction difficult. There was a problem of doing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. In addition to constructing a system in which the number of magnets and power supplies is reduced, the beam cross-sectional shape and the beam optics parameters are reduced in a small space. It is an object of the present invention to obtain a charged particle device that enables the ratio of the size in the direction to the size in the y direction to be arbitrarily changed.

[Means for Solving the Problems] In the charged particle device according to the present invention, a drive device that can rotate around a beam axis is attached to a quadrupole electromagnet so that the rotation angle can be adjusted.

[Operation] In the present invention, the quadrupole electromagnet is rotated by an arbitrary angle about the beam axis by a driving device so that the direction of the quadrupole magnetic field to be produced is changed in an arbitrary direction in a plane perpendicular to the beam axis. Can be taken. Therefore, by controlling the rotation angle around the beam axis and the strength of the quadrupole magnetic field, not only the convergence and divergence of the beam in the x and y directions but also the ratio of the beam cross-sectional shape in the x and y directions can be arbitrarily determined. Can be changed.

Embodiment An embodiment of the present invention will be described below with reference to FIGS.

In the figure, (1) is a quadrupole electromagnet, (4) is a beam duct, (5) is a stepping motor, (6) is a gear mounted on a shaft of the motor, and (7) is a center of the beam duct (4). The gear rotates as a shaft, and supports the quadrupole electromagnet (1). (8) is a support frame that allows the gear (7) to rotate smoothly, and (3) is a mount that fixes the support frame (8) and the stepping motor (5). Gear (6) meshes with gear (7).

Next, the operation will be described. When the stepping motor (5) is moved, the gear (6) rotates and the support frame (8)
The gear (7) supported by the shaft rotates. Gear (7)
Supports the quadrupole electromagnet (1), the magnetic field created by the quadrupole electromagnet (1) will therefore rotate about the beam duct (4). Therefore, in order to set the convergence and divergence of the beam in the x and y directions, and the degree of coupling of the emittance in the x and y directions, that is, the ratio of the size of the beam cross-sectional shape in the x and y directions to an arbitrary value. The rotation angle of the quadrupole magnetic field and the magnitude of the quadrupole magnetic field are determined.

FIGS. 3 and 4 show another embodiment, in which a quadrupole electromagnet (1), a stepping motor (5) and a gear (6) mounted on its shaft are mounted on a support frame (9), and a beam duct is mounted. A gear (7) is attached to a support frame (10) fixed to (4), and meshes with the gear (6) so that the support frame (9) can rotate smoothly about the beam duct (4). It has become. Therefore, in this case, the stepping motor (5) itself is configured to rotate together with the quadrupole electromagnet (1), and there is no need for a stand for supporting the entire apparatus.

In the above embodiment, the meshing of the gears is used, but a method using friction using a car or the like, or a power transmission method such as a belt or a chain may be used. Although a stepping motor is used, other drive devices may be used as long as they can be controlled.

[Effects of the Invention] As described above, according to the present invention, the quadrupole electromagnet is configured to be able to rotate at an arbitrary angle about the beam axis, so that the quadrupole electromagnet and the skew quadrupole electromagnet have been used. The adjustment of the beam parameters, which has been performed, can be achieved with an inexpensive structure, and there is an effect that the space in the beam trajectory direction for mounting the device is reduced.

[Brief description of the drawings]

FIG. 1 is an elevational sectional view of one embodiment of the present invention, FIG. 2 is a side elevational view, FIG. 3 is an elevational elevational view of another embodiment, FIG. 4 is a side elevational view, FIG. The figures are each a partial cross-sectional view of a conventional charged particle device, and FIG. 7 is a perspective view of the same. (1) ... 4-pole electromagnet, (4) ... beam duct,
(5) Stepping motor, (6) Gear,
(7) ... gear, (8) ... support frame. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. A charged particle device comprising: a quadrupole electromagnet; and a drive device for rotating the quadrupole electromagnet at an arbitrary angle about a charged particle orbit axis.