JPH0736360B2 - Injection device of magnetic resonance type accelerator - Google Patents

Description

TECHNICAL FIELD The present invention relates to an air core electromagnet for an inflector used in a magnetic resonance type accelerator having a circular orbit such as a weakly focused synchrotron and a weakly focused storage ring.

[Conventional technology]

A conventional magnetic resonance type accelerator having a circular orbit has, as an injector, an electromagnet called a kicker that operates at a high speed or an electromagnet called a perturbator, and an inflector that generates a magnetic field or an electric field in a direct current. ing. The inflector guides charged particles to the incident orbit. The kicker or perturbator displaces the equilibrium orbit so that charged particles injected from the inflector do not hit the inflector even if they travel around the orbit and come to the inflector again. Generally, the kicker displaces the entire equilibrium orbit, whereas two or three perturbators operate in synchronization to displace a part of the equilibrium orbit.

As shown in FIG. 5, the conventional magnetic resonance type accelerator has an inflator 11 for guiding charged particles to an incident orbit and an orbital equilibrium orbit.
12 and two sets of horizontally-focusing quadrupole electromagnets, which are provided at a plurality of positions on the equilibrium orbit, each of which is a dipole electromagnet 13 and arranged on both sides thereof.
14 and horizontal divergent quadrupole electromagnets 15 and a plurality of deflecting elements and focusing elements, and perturbators 16 to 18 which are provided at the ends of the focusing elements on both sides of the inflector 11 and move the equilibrium orbit 12. ing.

Here, the conventional inflector will be outlined.

Referring also to FIG. 6, the inflector 11 includes a return yoke 11b made of a ferromagnetic material (for example, ferrite) having a beam passage 11a formed therein. In the beam passage 11a, a return coil 11c is arranged along the beam passage 11a as shown, while the opening of the beam passage 11a has a septum coil 11d.
Covered by. The magnetic inflector 11 is arranged with the septum coil side inside as shown in FIG.

When a current is passed through the return coil 11c and the septum coil 11d to excite the magnetic inflector, lines of magnetic force, that is, a magnetic field are formed as indicated by solid arrows. That is, a magnetic field is formed in the beam passage 11a without leakage of magnetic flux due to the return yoke 11b and the septum coil 11d described above. Since the gap between the incident beam and the orbiting beam is small, the septum coil is formed as thin as possible, and since the strong magnetic field is generated, the septum coil is pulse-excited.

Then, the magnetic field described above guides the charged particles passing through the beam passage 11a to the incident orbit.

[Problems to be solved by the invention]

By the way, conventionally, the magnetic inflector is arranged in a straight line portion where an external magnetic field does not exist as shown in FIG. However, when the storage ring etc. is miniaturized into a circular storage ring without a straight line portion, the magnetic inflector has a magnetic field (main magnetic field).
Must be placed inside. However, when the conventional magnetic inflector is placed in the magnetic field, there is a problem that the main magnetic field is disturbed and the injector does not operate well.

An object of the present invention is to provide an injector used in a magnetic resonance type accelerator such as a small circular storage ring.

[Means for solving problems]

The injector according to the present invention is an insulative support in which a charged particle passage extending in a predetermined direction is formed, a first conductor portion disposed in the support, and extending in the predetermined direction, and a first conductor. A second conductor part which is mounted on a support body and extends in the predetermined direction around the part, the charged particle passage being located between the first and second conductor parts, and the first conductor part The second conductor portion has an air-core electromagnet (inflector) in which electric currents flow in directions opposite to each other and forms a magnetic field in the charged particle passage. The air-core electromagnet is pulse-excited to generate the magnetic field. It is characterized in that the charged particles passing through the charged particle passage are guided to the incident orbit.

〔Example〕

 The present invention will be described below with reference to examples.

First, the structure of the inflator applied to the present invention will be described with reference to FIGS. 1 (a) and 1 (b).

An insulative rectangular tube member (hereinafter referred to as a coil support member) 2 is formed in a bow shape, and one wall surface of the square tube member 2 has a penetrating portion extending radially outward and axially extending. Inside the coil support member 2, a coil (hereinafter referred to as an internal coil) 1 extending in the axial direction is disposed in contact with the inner wall surface of the support member 2. On the other hand, the magnetic shield coil 3 is mounted on the other wall surfaces except the wall surface where the penetrating portion is formed. Further, the septum coil 4 is attached to one wall surface so as to close the above-mentioned penetrating portion, and the penetrating portion serves as the charged particle passage 5.

Referring also to FIGS. 2 (a) and 2 (b), the circular storage ring has a circular core 7 having a cavity 6 formed therein. A ring-shaped vacuum duct 8 in which a circular orbit of charged particles is formed is arranged in the cavity 6 as shown in the drawing.
On the outer side of the vacuum duct 8 in the radial direction, a pair of ring-shaped main coils 9 are arranged in the cavity 6 so as to face each other at a predetermined interval. The inflector 10 is arranged near the vacuum duct 8 as shown in FIG. 2 (a), and guides the incident beam from the outside of the storage ring to the incident trajectory.

As shown in FIG. 3, the magnetic shield coil 3 and the septum coil 4 are connected, for example, to the (+) side of the power source, while the internal coil 1 is connected to the (-) side. That is, the magnetic shield coil 3, the septum coil 4 and the internal coil 1 are supplied with currents in opposite directions. A large pulse current is used for this current. That is, the inflector is pulse-excited. In this way, the inflector is pulse-excited (since a current is passed at a high current density), a strong magnetic field is generated in the charged particle passage 5. The charged particle passage 5
The magnetic field of is shielded by the magnetic shield coil 3 and the septum coil 4 and therefore does not leak to the outside. Also, the inflector has a beam incident time (for example, 1 μsec).
At, pulse excitation is performed so that the magnetic field (the magnetic field of the charged particle passage 5) becomes constant.

An example of the magnetic field generated by the pulse excitation described above is shown in FIG. 4 (where the center axis of the inflector is the origin and the radial direction is x
Magnetic flux density (Bz) with axis (horizontal axis) and vertical axis perpendicular to radial direction
And). As shown in FIG. 4, a bipolar magnetic field having a polarity opposite to that of the main magnetic field of the storage ring is generated in the inflector. If necessary, if a quadrupole magnetic field or a multipole field is superimposed on the dipole magnetic field in the inflector, the focusing force or aberration acting on the beam can be corrected.

Thus, since the inflector used in the present invention does not use the ferromagnetic return yoke, that is, the insulating coil supporting member is used, the inflector can be arranged in the magnetic field.

〔The invention's effect〕

As described above, according to the present invention, since the main magnetic field is not disturbed, it can be used for a circular magnetic resonance type accelerator. Further, the magnetic field formed in the charged particle passage does not leak outside.

Furthermore, since pulse excitation is performed, a relatively high magnetic field can be generated and a high energy beam can be injected.

[Brief description of drawings]

FIGS. 1 (a) and 1 (b) schematically show an air-core electromagnet (inflector) used in the present invention, and FIGS. 2 (a) and 2 (b) schematically show a circular storage ring. Fig. 3, Fig. 3 is a diagram showing power feeding to an air core electromagnet, Fig. 4 is a diagram showing magnetic field distribution by an inflector, Fig. 5 is a diagram schematically showing a conventional magnetic resonance type accelerator, and Fig. 6 is It is a figure which shows the structure of the conventional inflector. 1 …… Internal coil, 2 …… Coil support member, 3 …… Magnetic shield coil, 4 …… Septum coil, 5 …… Charged particle passage, 6
...... Cavity, 7 ...... Iron core, 8 ...... Vacuum duct, 9 ...... Main coil, 10 ...... Inflector, 11 ...... Inflector, 12 ...... Balanced orbit, 13 ...... Dipole electromagnet, 14 ...... Horizontal focusing quadrupole electromagnet, 1
5 …… Horizontal divergent 4-pole electromagnet, 16-18 …… Perverter.

Claims (1)

[Claims] 1. An injecting device for injecting charged particles into a magnetic resonance type accelerator having a circular orbit, an insulating support having a charged particle passage extending in a predetermined direction, the insulating support being disposed in the support, A first conductor portion extending in the direction of, and a second conductor portion that is mounted on the support body around the first conductor portion and extends in the predetermined direction. The charged particle passage is located between conductors, and
Electric currents are made to flow in opposite directions to the conductor part of the second conductor part and the second conductor part, and there is an air-core electromagnet forming a magnetic field in the charged particle passage, and the air-core electromagnet is pulse-excited, An injection device for a magnetic resonance type accelerator, wherein charged particles passing through the charged particle passage are guided to an incident orbit.