JP3016820B2 - Steering electromagnetic device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering electromagnet device used for a charged particle device such as a SOR device, for adjusting a trajectory of a charged particle beam.

[Prior Art] FIG. 3 is, for example, “Design of Incident Synchrotron” (UVSOR-7 March 198, published by Institute for Molecular Chemistry, March 1981).
1) It is sectional drawing of the conventional steering electromagnet apparatus shown on pages 43-45.

In the drawing, reference numeral (1) denotes a square frame-shaped yoke, which is assembled from first to fourth yoke parts (1a) to (1d). (2a) to (2d) are the yoke parts (1a) to (1
d) The first to fourth magnetic pole projections provided so as to project toward the center of the yoke (1), (3a) and (3b) are the first and second magnetic pole projections (2a) , (2b) wound around the first and second horizontal magnetic field exciting coils, (4a) and (4b) wound around the third and fourth magnetic pole projections (2c), (2d) First and second vertical magnetic field exciting coils.

FIG. 4 is a connection diagram showing an electrical connection relationship of each coil in FIG. 3, where (5) is a horizontal magnetic field exciting coil (3a) via a first magnetic switch (6). (3b)
(7) is connected to the respective vertical magnetic field exciting coils (4) via a second magnetic switch (8).
This is the second excitation power supply connected to (a) and (4b).

The horizontal magnetic field exciting coils (3a) and (3b) are the first coils.
The excitation power supply (5) is connected to each vertical magnetic field excitation coil (4
a) and (4b) are connected in series to the second excitation power supply (7).

In the conventional steering electromagnet apparatus configured as described above, a weak magnetic field (several hundreds to
000 kGauss) to adjust (steer) the trajectory of the charged particle beam and to compensate for beam trajectory shifts resulting from deflection and imperfections of the quadrupole magnet.

For example, as shown in FIG. 4, each coil (3a), (3b),
It is assumed that a horizontal magnetic field is generated in the X direction of the drawing and a vertical magnetic field is generated in the Y direction of the drawing according to (4a) and (4b). As a result, the charged particle beam traveling toward the front of the drawing sheet is deflected by receiving a force in the direction of the vector A orthogonal to the vector Z, which is the sum of the vector X and the vector Y.

Therefore, each coil (3a), (3b), (4a), (4b)
By adjusting the excitation amount and magnetism of each of the power supplies (5) and (7) and the magnetic switches (6) and (8), the direction and magnitude of each vector can be changed. Therefore, the correction direction and correction amount of the trajectory of the charged particle beam can be arbitrarily adjusted.

[Problem to be Solved by the Invention] In the conventional steering electromagnet apparatus configured as described above, in order to generate a horizontal magnetic field and a vertical magnetic field, two sets of excitation coils (3a), ( 3b),
(4a), (4b), power supplies (5), (7), and magnetic switches (6), (8) are required, so that a remote control device (not shown) is complicated, and However, there was a problem that it became expensive. In the case of the magnetic pole shape as shown in FIG. 3, if the adjacent magnetic poles are too close to each other, the mutual magnetic field distribution shape is disturbed. There were also problems such as becoming. In particular, in a heavy particle beam transport system used for medical treatment, the beam diameter is large, so that it is necessary to increase the interval at which the magnetic field is generated, which further increases the size and cost of the entire apparatus There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a steering electromagnet device capable of simplifying and miniaturizing the entire structure including a power supply and being inexpensive. And

[Means for Solving the Problems] In a steering electromagnet device according to the present invention, a pair of deflection magnetic field excitation coils are provided rotatably in a state of being opposed to each other across a trajectory of a charged particle beam.

[Operation] In the present invention, by adjusting the rotation angle of the pair of deflection magnetic field excitation coils, the deflection angle of the trajectory of the charged particle beam is adjusted, and the excitation intensity of the deflection magnetic field excitation coils is adjusted. Adjusts the amount of deflection of the orbit.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First
FIG. 1 is a configuration diagram showing a steering electromagnet device according to one embodiment of the present invention.

In the drawing, reference numeral (11) denotes a gantry having a bearing (11a), and (12) surrounds the outer side of the trajectory (O) of the charged particle beam and is supported rotatably on a bearing (11a). An annular yoke, (13) is a pair of magnetic pole projections provided on the inner circumference of the yoke (12) so as to face each other with the track (O) interposed therebetween, and (14) is a respective magnetic pole projection ( 13) is a pair of coils for exciting the deflection magnetic field wound around 13).

(15) is an annular rack provided along the side surface of the yoke (12), (16) is a motor provided on the gantry (11), and the motor (16) The yoke (12) is rotated and stopped via the pinion (17) meshing with 15).

FIG. 2 is a connection diagram of the deflecting magnetic field exciting coil (14) of FIG. 1. In FIG. 2, (18) is an exciting power supply, and a pair of deflecting magnetic field exciting coils (14) is an exciting power supply ( 18) are connected in series.

In the steering electromagnet device configured as described above, when the pair of deflecting magnetic field exciting coils (14) are excited by the exciting power supply (18), the vector shown in FIG. A weak deflection magnetic field (dipole magnetic field) as shown in Z is generated. As a result, a high-energy charged particle beam such as an electron beam traveling toward the front of the drawing sheet is deflected by receiving a force in a vector A direction orthogonal to the vector Z.

At this time, in the apparatus of the above embodiment, since the rotation angle θ of the yoke (12) can be adjusted by 360 ° by driving the motor (18), the pair of deflection magnetic field exciting coils (14) are Can be rotated about the center of the magnetic field. Therefore, the direction of the vector Z, that is, the direction of the vector A is set to 360
゜, whereby the deflection angle of the trajectory (O) of the charged particle beam can be arbitrarily changed. Therefore, the deflection angle of the beam trajectory (O) can be adjusted by rotating the yoke (12) while checking the beam trajectory (O) with a beam monitor (not shown).

Further, the absolute value of the vector A, that is, the deflection amount of the beam trajectory (O) can be adjusted by increasing or decreasing the exciting current of the deflecting magnetic field exciting coil (14), that is, by changing the exciting intensity.

In such a steering electromagnet device, only one pair of the magnetic pole protrusion (13) and the deflecting magnetic field exciting coil (14) is required, and a magnetic switch conventionally required can be omitted, and a remote control device (not shown) is also provided. For example, the entire structure including the power supply can be simplified and miniaturized, such as simplification, so that the overall cost can be reduced. Further, since there is no problem of interference with the adjacent magnetic poles, it is not necessary to take an excessively large magnetic pole interval, and the whole can be downsized.

In the above embodiment, the annular yoke (12) is shown, but other shapes may be used.

In the above embodiment, the yoke (12) is shown, but the yoke (12) may be omitted, and the deflection magnetic field exciting coil (14) may be supported by a simple support member.

Further, in the above embodiment, the deflection magnetic field exciting coil (14)
Is shown wound around the magnetic pole projection (13), but the deflection magnetic field exciting coil (14) may be an air-core coil.

Further, in the above embodiment, the rack (15) and the motor (16) are used to rotate the deflection magnetic field exciting coil (14).
And the pinion (17) are used, but other gears or belts may be used. Moreover, you may make it rotate manually.

In the above embodiment, an electron beam is shown as a charged particle beam, but another beam such as a heavy particle beam may be used.

[Effects of the Invention] As described above, in the steering electromagnet apparatus of the present invention, the deflection magnetic field exciting coil is rotatably provided in a state where the coils are opposed to each other across the trajectory of the charged particle beam, and the rotation angle is set. By adjusting the deflection angle of the beam trajectory by adjusting it, and by adjusting the excitation intensity, the amount of deflection of the beam trajectory is adjusted, so that the beam trajectory can be adjusted with a pair of deflection magnetic field excitation coils. Thus, the entire structure including the power supply can be simplified and miniaturized, and as a result, the space can be saved and the device can be made inexpensive.

[Brief description of the drawings]

FIG. 1 is a structural view showing a steering electromagnet device according to an embodiment of the present invention, FIG. 2 is a connection diagram of a deflection magnetic field exciting coil of FIG. 1, and FIG. 3 is a cross-sectional view of an example of a conventional steering electromagnet device. FIG. 4 is a connection diagram of each coil of FIG. In the figure, (14) is a deflection magnetic field exciting coil, and (O) is an orbit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. A pair of deflecting magnetic field exciting coils which are rotatably provided opposite to each other across a trajectory of a charged particle beam and generate a deflecting magnetic field, and are electrically connected to the deflecting magnetic field exciting coils. Power supply for excitation that is provided, while adjusting the deflection angle of the charged particle beam by rotating the deflection magnetic field excitation coil, and increasing or decreasing the excitation current of the deflection magnetic field excitation coil to increase the excitation intensity. A steering electromagnet device, wherein the amount of deflection of the charged particle beam is adjusted by changing the amount.