JPH0582299A - Synchrotron - Google Patents

Abstract

PURPOSE:To provide a synchrotron with which an electric current tracking can be dispensed and in which a conventional electric power supply can be used. CONSTITUTION:A deflecting electromagnet 5, a converging quadruplex pole electromagnet 6 and a diverging quadruplex pole electromagnet 7 constituted so as to form respective prescribed magnetic fields in the same electric current value, are connected in series to each other, and these deflecting electromagnet 5, converging quadruplex pole electromagnet 6 and diverging quadruplex pole electromagnet 7 connected in series to each other, are set to be impressed by means of an electric power supply 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchrotron having a deflection electromagnet and a quadrupole electromagnet.

[0002]

2. Description of the Related Art A synchrotron for accelerating electrons and the like is widely used for research of elementary particles and utilization of synchrotron radiation.

A conventional synchrotron is shown in FIG.

In the conventional synchrotron 1, the generated electrons are accelerated by the linear accelerator 2 to a low energy of, for example, several tens MeV, and the accelerated electron beam is maintained in an ultrahigh vacuum state via the low energy transport tube 3. The electron beam incident on the vacuum chamber 4 is converged or diverged by the converging quadrupole electromagnet 6 or the diverging quadrupole electromagnet 7, respectively, and is bent by the deflecting electromagnet 5, while the electron beam is radiated in the high frequency cavity 8 by, for example, 1 GeV. Is accelerated to a high energy, and the accelerated electron beam is emitted to a storage ring (not shown) via the high energy transport tube 9.

The above-mentioned deflecting electromagnet 5 deflects the electron beam, and thus, for example, in FIG. 4, it forms a magnetic field from the front to the back of the paper.

A deflection electromagnet power source 10 is connected to the deflection electromagnet 5.

Although the deflecting electromagnet power source 10 is actually connected to all the deflecting electromagnets 5, only one is shown in FIG.

The deflection electromagnet 5 is constructed so that the current value supplied to the deflection electromagnet 5 increases as the electron beam energy increases.

The above-mentioned focusing quadrupole electromagnet 6 is designed to focus the electron beam in a direction perpendicular to the traveling direction of the electron beam and horizontal to the arrangement surface of the synchrotron 1 (hereinafter, simply referred to as X direction). On the other hand, the divergence quadrupole electromagnet 7 narrows the electron beam in a direction perpendicular to the traveling direction of the electron beam and also perpendicular to the arrangement surface of the synchrotron 1, in other words, the vertical direction (hereinafter, simply referred to as Y direction). It has become.

Further, a converging quadrupole electromagnet 6 and a diverging quadrupole electromagnet 7 are connected to a converging electromagnet power supply 11 and a diverging electromagnet power supply 12, respectively, so that the converging quadrupole electromagnet 6 can be used in accordance with an increase in electron beam energy. The current value supplied to the diverging quadrupole electromagnet 7 is increased.

FIG. 5 shows the details of the deflection electromagnet 5 in a sectional view taken along the line AA of FIG.
The −Y coordinate direction is also shown.

In the deflection electromagnet 5, exciting coils 15a and 15b are wound around the yoke 13, and the exciting coils 15a and 15b
By passing a current through 15b, magnetic poles 14a and 14b
A magnetic field parallel to the plane of the drawing is formed between them to deflect the electron beam running in the vacuum container 4.

FIG. 6 shows the details of the focusing quadrupole electromagnet 6 in a sectional view taken along the line BB of FIG.

The converging quadrupole electromagnet 6 includes four magnetic poles 17a, each having a rounded tip, on the inside of a substantially octagonal yoke 16.
17b, 17c, 17d are attached, and the vacuum container 4 is positioned in a region having a radius R ₀ connecting the tips of the magnetic poles.
A magnetic field 19 shown by a broken line is formed by passing a current through the exciting coils 18a, 18b, 18c, 18d wound around 7a, 17b, 17c, 17d, respectively.

FIG. 7 shows the Y-direction component B _y of the magnetic field 19 on the X-axis by a solid line, for example.

As can be seen from FIG. 7, the electron beam on the X-axis is subjected to the Lorentz force toward the origin with a force proportional to the Y-direction component B _y .

Since the Y-direction component B _y increases substantially in proportion to the distance from the origin, the electron beam has dB
_y / dx, that is, the convergence force proportional to the slope of the solid line and the distance from the origin acts.

This dB _y / dx is called a quadrupole magnetic field.

As described above, the focusing quadrupole electromagnet 6 is constructed so as to focus the electron beam on the X axis. For example, an opposite Lorentz force acts on the electron beam on the Y axis. Since the electron beam is diverged by using the quadrupole electromagnet 7 for divergence, the electron beam on the Y axis is converged.

For this reason, the divergent quadrupole electromagnet 7 is constructed by reversing the energizing direction of the converging quadrupole electromagnet 6.

Therefore, the Y direction component B _y of the magnetic field by the divergent quadrupole electromagnet is as shown by the broken line in FIG. 7, and the electron beam on the X axis is proportional to the quadrupole magnetic field dB _y / dx and the distance from the origin. Although the diverging force described above acts, the above-described focusing force acts on the electron beam on the Y axis.

That is, the electron beam as a whole is subjected to the focusing action by the actions of both the focusing quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7.

The deflecting electromagnet 5, the focusing quadrupole electromagnet 6, and the diverging quadrupole electromagnet 7 are as shown in FIG.
Power source 10 for deflecting electromagnet, power source 11 for converging electromagnet,
A power source 12 for the diverging electromagnet is connected, and an electric current is supplied independently.

The synchrotron 1 is further provided with a control unit 20 for controlling these current values.

By the way, when supplying the above-mentioned current,
Depending on the value of the electron beam energy, the deflection electromagnet 5,
The current flowing through the focusing quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7 must be accurately controlled between the electromagnets, and this is called current tracking.

If the accuracy of the current tracking is poor, it may cause disappearance of the electron beam during acceleration, decrease in electron beam acceleration efficiency, decrease in reproducibility for each operation, and the like.
It is necessary to configure the power supply 10 for the deflection electromagnet, the power supply 11 for the converging electromagnet, and the power supply 12 for the diverging electromagnet so that the current tracking can be performed accurately.

On the other hand, in order to avoid such accurate current tracking, an AG (Alternating G) as shown in FIG. 9 is used.
A synchrotron equipped with a radient type deflection electromagnet is often used.

In the synchrotron 21, the generated electrons are accelerated by the linear accelerator 2 to a low energy of, for example, several tens MeV, and the accelerated electron beam is maintained in an ultrahigh vacuum state via the low energy transport tube 3. The electron beam incident on the vacuum container 4 is directed to the AG-type deflection electromagnet 2
While being bent at 2 and converging or diverging, it is accelerated in the high frequency cavity 8 to a high energy of, for example, 1 GeV, and the accelerated electron beam is emitted to a storage ring (not shown) via a high energy transport tube 9. Has been done.

The AG-type deflection electromagnet 22 has a power supply 2
3 is connected, and the power supply 23 is provided with a control unit 28 that controls the output current of the power supply 23.

FIG. 10 shows the details of the AG-type deflection electromagnet 22 in a sectional view taken along the line CC of FIG.

The AG-type deflection electromagnet 22 has exciting coils 26a and 26b wound around a yoke 24, and a current is passed through the exciting coils 26a and 26b to generate a magnetic pole 25a.
And 25b and between the magnetic poles 27a and 27b, a magnetic field is formed to deflect the electron beam running in the vacuum chamber 4.

Further, the magnetic pole 25 of the AG-type deflection electromagnet 22
The a and 25b are inclined so as to open to the outside, and are configured to exert a converging action in the X-axis direction on the electron beam running in the vacuum container 4.

Similarly, the magnetic pole 2 of the AG-type deflection electromagnet 22
7a and 27b are inclined to open inward,
The electron beam running in the vacuum container 4 is configured to have a diverging action in the X-axis direction.

Of these magnetic poles, generally, the first quarter of the AG type deflection electromagnet 22 is the converging magnetic poles 25a and 25b, the next one half is the diverging magnetic poles 27a and 27b, and the last approximately four.
One half is the magnetic poles 25a and 25b for converging.

That is, the AG type deflection electromagnet 22 not only acts as a deflection electromagnet, but also has a function as a focusing quadrupole electromagnet and a diverging quadrupole electromagnet.

Therefore, the power source is only the power source 23,
The current tracking described above can be avoided.

Further, since the converging quadrupole electromagnet and the diverging quadrupole electromagnet are unnecessary, the circumference of the synchrotron can be shortened.

[0038]

However, in the synchrotron 1 provided with the deflection electromagnet 5, the focusing quadrupole electromagnet 6 and the divergence quadrupole electromagnet 7 described above, if current tracking is attempted accurately, the power supply for the deflection electromagnet is required. 1
0, power source 11 for convergent electromagnet and power source 12 for divergent electromagnet
Has to be a highly responsive power source, which causes a problem of high manufacturing cost.

Further, the synchrotron 21 having the AG type electromagnet 22 for deflection does not require troublesome current tracking, but has the following problems.

That is, in the synchrotron 1, so-called radiation damping occurs and the electron beam becomes thin as the radiated light is radiated by the deflection electromagnet 5 and the like, but in the synchrotron 21 having the AG-type deflection electromagnet 22, As a result of radiation anti-damping, the electron beam becomes thicker, and the electron beam collides with the vacuum container 4 and disappears.

Therefore, it is necessary to shorten the time for accelerating the electron beam, that is, the start-up time so that the electron beam can be emitted to the storage ring before it becomes thick.

For example, in the synchrotron 1, the emission period is set to, for example, 1 hertz, that is, 0.5 seconds, and then the accelerated electron beam is emitted to the storage ring and then 0.5
In the synchrotron 21, the emission period is, for example, 20 hertz.

Therefore, the power supply 23 of the synchrotron 21
Must use an expensive pulsed power supply, not an ordinary power supply.

Further, shortening the time for raising the current to a predetermined value increases the rate of change in the current flowing through the AG-type deflection electromagnet 22 and increases the AC resistance. And the AG-type bending magnet 2 for this high voltage.
2 or the problem that the insulation performance of the power supply 23 or the like must be improved.

The present invention has been made in consideration of the above circumstances, and an object thereof is to provide a synchrotron which does not require current tracking and can use a conventional power supply.

[0046]

In order to achieve the above object, the synchrotron of the present invention, as set forth in claim 1, is configured so as to form a predetermined magnetic field with the same current value. , A converging quadrupole electromagnet and a diverging quadrupole electromagnet are connected in series, and the deflection electromagnet, the converging quadrupole electromagnet and the diverging quadrupole electromagnet connected in series are applied by a single power source. is there.

[0047]

[Operation] By connecting the deflecting electromagnet, the focusing quadrupole electromagnet and the diverging quadrupole electromagnet together with the power source in series,
Since the current values for exciting the electromagnets are the same, it is not necessary to perform current tracking that requires high accuracy.

Further, since the pulse power supply is not necessary, the voltage of the power supply may be the conventional voltage, the manufacturing cost of the power supply is low, and the insulation is easy.

[0049]

Embodiments of the synchrotron according to the present invention will be described below with reference to the accompanying drawings.

The same parts as those described in the prior art are designated by the same reference numerals as those in FIGS. 4 to 10 and their description is omitted.

FIG. 1 shows a first embodiment of the synchrotron of the present invention.

In the synchrotron 31 of this embodiment, the deflecting electromagnet 5, the focusing quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7 each configured to form a predetermined magnetic field with the same current value are shown in FIG. The deflection electromagnet 5, the focusing quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7 connected in series are applied by the power source 32.

The synchrotron 31 is further provided with a power source 32.
Is provided with a control unit 33 for controlling the current value output by.

In order to configure the deflection electromagnet 5, the focusing quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7 as described above, first, the deflection electromagnet 5 forms a predetermined magnetic field when the electron beam energy becomes maximum. The current value to be passed through the deflection electromagnet 5 is determined so that the electron beam can be orbited.

Next, the converging quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7 are formed as follows so that the converging quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7 form respective predetermined magnetic fields at the determined current values. To design.

Converging quadrupole electromagnet 6 and diverging quadrupole electromagnet 7
Quadrupole magnetic field dB _y / dx formed by _{the, dB y / dx = 2μ 0} NI / R 0 2 ... (1) and represented.

Here, μ ₀ is the vacuum permeability, N is the number of turns, I is the current value, and R ₀ is the radius described in FIG. 6, and is hereinafter referred to as the bore radius.

[0058] As can be seen in formula (1), to set the dB _y / dx for a current I to a predetermined value, N, and R
_At least one of ₀ may be adjusted.

For example, the exciting coils 18a, 18b, 18c, 1 of the focusing quadrupole electromagnet 6 are set so that a predetermined quadrupole magnetic field dB _y / dx is obtained with respect to the current value determined as described above.
The number of windings N of 8d is adjusted, and if the number of windings N cannot be adjusted, the shapes of the magnetic poles 17a, 17b, 17c, 17d are changed to adjust the bore radius R ₀ .

In order for the converging quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7 to form respective predetermined magnetic fields at the determined current value, the number of windings N or the bore radius R _0.
In addition to changing the quadrupole magnetic field dB _y / dx by adjusting, the focusing quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7
The length may be changed.

Further, by combining the adjustment of the number of turns N, the bore radius R ₀ and the magnet length, a wider range of adjustment can be performed.

Next, the operation of this embodiment will be described.

While the incident electron beam is accelerated in the high frequency cavity 8, the deflection electromagnet 5, the focusing quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7 designed as described above are controlled by the control unit 33. When excited by the power source 32, the electron beam circulates in the vacuum container 4 while increasing its energy.

In this case, the beam energy of the electron beam and the magnetic fields to be formed by the deflecting electromagnet 5, the focusing quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7 are proportional to each other, so that the deflection designed with the maximum beam energy is performed. The electromagnet 5, the focusing quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7 are
Even during acceleration, a magnetic field corresponding to each beam energy is formed, and the electron beam does not collide with the vacuum container 4.

Since the deflecting electromagnet 5, the focusing quadrupole electromagnet 6 and the diverging quadrupole electromagnet 7 are connected in series, the current values flowing through them are the same among the three electromagnets.

Therefore, there is no need to perform current tracking as in the conventional case.

Next, a second embodiment of the synchrotron of the present invention will be described.

As shown in FIG. 3, the synchrotron 41 of this embodiment has an AG type deflection electromagnet 4 as a deflection electromagnet configured to form a predetermined magnetic field with the same current value.
4. Auxiliary focusing quadrupole electromagnet 4 as a focusing quadrupole electromagnet
2 and auxiliary divergent quadrupole electromagnets 43 as divergent quadrupole electromagnets are connected in series as in FIG. 2, and these AG type deflection electromagnets 44, auxiliary focusing quadrupole electromagnets 42 and auxiliary divergence quadrupoles are connected in series. The electromagnet 43 is applied by the power supply 45.

The synchrotron 41 is further provided with a power supply 45.
The control unit 46 for controlling the current value output by

The AG deflection electromagnet 44 of this embodiment is the same as the conventional AG deflection electromagnet 22 described with reference to FIG.
Unlike the above, the inclination of each magnetic pole is made gentle.

That is, the angle formed by the magnetic pole surfaces facing each other of the AG type deflection electromagnet 44 is the angle formed by the magnetic pole surfaces of the magnetic poles 25a and 25b of the AG type deflection electromagnet 22, or 27a and 2.
It is configured to be closer to parallel than the angle formed by the magnetic pole surface of 7b.

The auxiliary converging quadrupole electromagnet 42 and the auxiliary diverging quadrupole electromagnet 43 are constructed so as to compensate for the decrease in the converging force and the diverging force due to the gentle inclination of the magnetic poles of the AG type deflection electromagnet 122.

In order to form each of the predetermined magnetic fields with the same current value as described above, the AG type deflection electromagnet 44, the auxiliary focusing quadrupole electromagnet 42, and the auxiliary diverging quadrupole electromagnet 43 have the first configuration. The design may be similar to that described in the embodiment.

Next, the operation of the second embodiment will be described.

Since the magnetic poles of the AG type deflection electromagnet 44 are made gentler than the inclination of the magnetic poles 25a, 25b or 27a, 27b of the conventional AG type deflection electromagnet 22, the converging force or diverging force thereof is the AG type. It is weaker than the deflection electromagnet 22.

Therefore, even if the electron beam emits the radiated light when passing through the AG-type deflection electromagnet 44, the radiation anti-damping does not occur unlike the conventional case.

That is, since the electron beam does not become thick and collide with the vacuum container 4 and disappear, it is not necessary to shorten the start-up time.

Therefore, the power supply 45 can use a normal power supply, and it is not necessary to consider the problem of insulation against high voltage.

Further, as in the first embodiment, since the AG type deflection electromagnet 44, the auxiliary focusing quadrupole electromagnet 42 and the auxiliary divergence quadrupole electromagnet 43 are connected in series, the same current is always applied to each electromagnet. Flows.

Therefore, there is no need to perform current tracking.

Since the AG-type deflection electromagnet 44 also functions as a focusing electromagnet and a diverging electromagnet, the AG-type deflection electromagnet 44 depends on the operation pattern of the synchrotron.
If the desired converging action or diverging action is obtained by itself, either one of the auxiliary focusing quadrupole electromagnet 42 and the auxiliary diverging quadrupole electromagnet 43 may be omitted.

[0082]

As described above, the deflection electromagnet, the converging quadrupole electromagnet, and the diverging quadrupole electromagnet, each of which is configured to form a predetermined magnetic field at the same current value, are connected in series, and are connected in series. Since the deflection electromagnet, the focusing quadrupole electromagnet, and the divergence quadrupole electromagnet are applied by a single power source, the current values for exciting each electromagnet are the same, and current tracking that requires high accuracy is performed. There is no need to do this, and a single power supply is sufficient, so the power supply space is small.

Further, there is no room for variations in current tracking, which causes fluctuations in the electron beam, so that the electron beam reproducibility is improved and the problem that the emission current value of the electron beam fluctuates is solved, and the reliability of the synchrotron is improved. Is improved.

Further, since the pulse power supply is not necessary, the voltage of the power supply may be the conventional voltage, the manufacturing cost of the power supply is low, and the insulation is easy.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of a synchrotron according to the present invention.

FIG. 2 is a deflection electromagnet of the first embodiment, a focusing electromagnet,
3 is a schematic diagram showing a connection relationship between a diverging electromagnet and a power supply.

FIG. 3 is a plan view showing a second embodiment of the synchrotron of the present invention.

FIG. 4 is a plan view showing a conventional synchrotron.

FIG. 5 is a cross-sectional view of a deflection electromagnet used in a conventional synchrotron.

FIG. 6 is a cross-sectional view of a focusing quadrupole electromagnet used in a conventional synchrotron.

FIG. 7 is a graph showing magnetic field distributions of a focusing quadrupole electromagnet and a diverging quadrupole electromagnet.

FIG. 8 is a schematic diagram showing a connection relationship of a deflection electromagnet, a focusing quadrupole electromagnet, a diverging quadrupole electromagnet, and a power source corresponding to each of them in a conventional synchrotron.

FIG. 9 is a plan view of a synchrotron using a conventional AG-type deflection electromagnet.

FIG. 10 is a cross-sectional view of a conventional AG type electromagnet for deflection.

[Explanation of symbols]

 2 linear accelerator 4 vacuum container 5 deflection electromagnet 6 focusing quadrupole electromagnet 7 divergence quadrupole electromagnet 8 high frequency cavity 32 power supply 33 control unit 42 auxiliary focusing quadrupole electromagnet 43 auxiliary divergence quadrupole electromagnet 44 AG type deflection electromagnet 45 power supply 46 control Department

Claims (1)

[Claims] 1. A deflection electromagnet, a focusing quadrupole electromagnet and a diverging quadrupole electromagnet, each of which is configured to form a predetermined magnetic field at the same current value, are connected in series, and the deflection electromagnet is connected in series. A synchrotron characterized in that the focusing quadrupole electromagnet and the diverging quadrupole electromagnet are applied by a single power source.