JPH065396A - Insert light source of particle accelerator - Google Patents

Abstract

PURPOSE:To omit perturbator as used according to the conventional technique, save the installation space to a great extent compared with the arrangement where an insert light source and a perturbator are installed individually, and provide applicability even to a small-sized particle accelerator which can not secure a good straight part for an accumulation ring. CONSTITUTION:A plurality of electric magnets 30 configured with a core 31 surrounding an accumulating ring 5 and a wiggler coil 32 fitted on the core are installed on the outside of the accumulating ring in in-line arrangement, and perturbator coils 35 to constitute a perturbator by energizing the cores uniformly are furnished on both sides of the accumulating ring. In normal operation, current is fed to the wiggler coils to permit serving as an insert light source, and when charged particles are injected, current is fed to the perturbator coil to allow working as a perturbator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insertion light source such as a wiggler or an undulator provided in a particle accelerator such as a synchrotron.

[0002]

2. Description of the Related Art In recent years, a relatively small synchrotron having a diameter of 10 m or less is being developed, and synchrotron radiation light (SOR light), which is radiation light emitted from such synchrotron, is utilized. For example, it is expected to be applied to various fields such as manufacturing of VLSI circuits, diagnosis in the medical field, molecular analysis, and structural analysis.

FIG. 4 shows an outline of the synchrotron. In this synchrotron, an electron beam generated by an electron generator 1 such as an electron gun is accelerated by a linear accelerator (linac) 2 to near the speed of light, deflected by a deflecting electromagnet 3 and then stored in a storage ring 5 via an inflector 4. Incident. The electron beam incident on the storage ring 5 is converged by the converging electromagnets 7 ... While being given energy by the high-frequency acceleration cavity 6 and is deflected by the deflection electromagnets 8 ... Then, when the SOR light is deflected by the deflection electromagnet 8, the SOR light is emitted and emitted to, for example, the exposure device 10 via the beam line 9 which is a light extraction line for use.

In the above synchrotron,
When the electron beam is incident on the storage ring 5 via the inflector 4, it is necessary to instantaneously change the orbit of the electron beam already circulating in the storage ring 5. Is provided.

As shown in FIG. 5, the perturbator 11 has a coil (perturbator coil) 1 on both sides of a storage ring 5 (the illustrated example has an oval cross section).
2 and 12, side cores 13 and 13 made of ferrite are provided outside them, and upper and lower cores 14 and 14 are provided above and below the storage ring 5, respectively. , 14, 14 surrounds the circumference of the storage ring 5 over the entire circumference. And, when the electron beam is incident,
A magnetic flux that penetrates the storage ring 5 vertically around the coils 12 and 12 by energizing the coils 12 and 12 from a power source (not shown) for a very short time in synchronization with the operation of the inflector 4 (broken line in the figure) (Indicated by a symbol) is momentarily formed, and the magnetic force causes a force to laterally displace the electron beam circulating in the storage ring 5 to instantaneously change the trajectory. is there. After changing the orbit by the perturbator 11 and injecting the electron beam in this way, the operation of the perturbator 11 is stopped until the electron beam is incident again, and the electron beam is almost in the center of the storage ring 5. It will circulate steadily.

By the way, in recent years, it has been considered to incorporate a wiggler or an undulator, which is generally called an insertion light source, into the linear portion of the storage ring 5 of the synchrotron as described above. The wiggler and undulator are both for deflecting and meandering the electron beam by applying a periodic magnetic field along the linear orbit of the electron beam, thereby extracting strong SOR light of a specific wavelength.

FIG. 6 shows an outline of a conventional general wiggler. This wiggler 20 has a large number of permanent magnets 21 ... Which are vertically paired and whose polarities are alternately changed above and below the straight portion of the storage ring 5 along the longitudinal direction of the straight portion of the storage ring 5. They are arranged side by side, and the upper and lower permanent magnets 21 and 21 are configured to generate a magnetic flux that vertically penetrates the storage ring 5 as shown by the arrows in the figure and that the directions thereof are alternately inverted. In such a wiggler 20, a periodic magnetic field is applied to the electron beam passing through the storage ring 5 so that the electron beam meanders in a direction perpendicular to the magnetic flux, that is, in the horizontal direction. The radiant light is emitted to the light, and the light has high intensity near a specific wavelength. Further, in the case of an undulator, radiated light from each part interferes to obtain quasi-monochromatic light. Although the wiggler 20 in the illustrated example has the permenders 23 ... As the magnetic pole material between the adjacent permanent magnets 21, the permender 23 is not necessarily provided and may be omitted.

[0008]

When an insertion light source such as the above-mentioned wiggler or undulator is to be provided in the synchrotron as shown in FIG. 4, those wiggler or undulator are stored in the storage ring 5. Although it must be incorporated in the straight line portion, in a small synchrotron, as shown in FIG. 4, in the straight line portion of the storage ring 5, the focusing electromagnet 7, the high frequency acceleration cavity 6, the inflector 4, the perturbator 11, etc. Since a large number of various types of equipment are usually provided, it may not be possible to secure a linear portion for installing an insertion light source in addition to them. Therefore, in such a case, it is necessary to take measures such as increasing the diameter of the storage ring 5 to extend the linear portion, or providing a detour having a linear portion for installing the insertion light source. However, this is not preferable because it causes an increase in size and complexity of the entire device.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an insertion light source having a structure that can be incorporated in a small particle accelerator.

[0010]

According to the present invention, a large number of electromagnets whose polarities are periodically changed are arranged side by side in the length direction of a storage ring on the outside of a linear portion of the storage ring in a particle accelerator such as a synchrotron. An insertion light source such as a Wiggler having a structure in which charged particles passing through the storage ring are deflected by the magnetic force of the electromagnets to extract emitted light, and each electromagnet includes a core surrounding the storage ring and each of the cores. Is formed by wiggler coils attached to the respective cores, and is provided on both sides of the storage ring so as to penetrate through the respective cores to uniformly excite the respective cores. The present invention is characterized in that a pertabeta coil for constituting a pertabeta is provided.

[0011]

In the insertion light source of the present invention, attention is paid to the fact that the pertabeta in the particle accelerator operates only for a very short time when charged particles are incident, and that the pertabeta and the insertion light source do not operate simultaneously. It is configured so that it can be switched to a perta beta.
That is, the insertion light source of the present invention operates as a normal insertion light source, that is, a wiggler or undulator, by periodically energizing each wiggler coil to individually excite each core to periodically change the polarity of each electromagnet. However, when injecting charged particles into the storage ring, the energization to each wiggler coil is stopped, and the pertabeta coil that penetrates through each core on both sides of the storage ring is energized. ,
Each core is uniformly excited to operate as a perturber.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view showing a schematic configuration of a wiggler which is an embodiment of the present invention, FIG. 2 is a front sectional view thereof, and reference numeral 5 in the drawing denotes a straight portion of a storage ring 5 in a synchrotron shown in FIG. , 30 are electromagnets provided outside the vacuum tube that constitutes the storage ring 5.

A plurality (three in the present embodiment) of electromagnets 30 are arranged at predetermined intervals along the lengthwise direction of the straight portion of the storage ring 5. Each electromagnet 30
Are respectively a core 31 made of ferrite surrounding the vacuum tube of the storage ring 5, and wiggler coils 32, 3 mounted on both sides of the core 31 to excite the core 31.
2 and a power source (not shown) for energizing the wiggler coil 32. The width dimension of the core 31 of each electromagnet 30 (dimension in the lengthwise direction of the storage ring 5) in the above-described embodiment is that of the core 31 of the electromagnet 30 positioned in the middle because the periodic magnetic field changes smoothly. The width dimension is about twice as large as the width dimension of the core 31 of the two electromagnets 30 located at both ends.

On both sides of the storage ring 5, each core 3 is provided.
A perturbator coil 35 penetrating the inside of the coil 1 is provided. The perta beta coil 35 is made of a copper bar, and one end sides thereof are connected to each other by a connecting bar 36.
The pulse power supply 37 is connected to the other end side. This pertabeta coil 35 uniformly excites each core 31 ...
It is for constructing a perturber as shown in.

The wiggler having the above-described structure is capable of operating both the wiggler and the pertabeta by selectively energizing one of the wiggler coil 32 and the pertabeta coil 35. It can be used by switching to a pertabeta.

That is, this wiggler energizes each wiggler coil 32 to excite each core 31 individually, and alternately changes the polarities of the electromagnets 30.
Similarly to the wiggler 20 using the permanent magnet 21 as shown in FIG. 3, a periodic magnetic field is applied to the electron beam passing through the storage ring 5, whereby the electron beam is deflected and meanders, and the emitted light is emitted from there. Is something that can be taken out.

When the electron beam is incident on the storage ring 5, the power supply to each wiggler coil 32 is stopped and the pulse power source 37 is supplied to the pertabeta coil 35 in synchronization with the inflector 4 (see FIG. 4). The cores 31 are uniformly excited by the pertabeta coils 35 by energizing the cores from the above. In this case, the cores 31 act as pertabetas and the orbit of the electron beam is instantaneously changed, so that the electron beam can be incident without any trouble. It is possible. Since it can be used as a perturber in a very short time, it can be used again as a wiggler by stopping the energization of the pertabeta coil 35 and energizing the wiggler coil 32 thereafter.

As described above, since the above wiggler can be switched to the perturber as needed, by omitting the conventional pertabeta and installing the above wiggler instead, the functions of both the pertabeta and the wiggler can be achieved. Can be secured. Therefore, unlike the conventional case, it is not necessary to separately install the pertabeta and the wiggler, and as a result, it is possible to greatly save the installation space as compared with the case of installing them separately,
It is suitable to be applied to a small synchrotron in which a sufficient straight line portion cannot be secured in the storage ring 5.

Although the wiggler of the above embodiment has three electromagnets 30, the number of electromagnets 30 may be set to, for example, five as shown in FIG. 3 or more. As in the embodiment, the number of the electromagnets 30 located at both ends is odd so that the polarities are the same, and the width of the core 31 of the electromagnet 30 located in the middle is the same as the core 31 of the electromagnets 30 located at both ends. Width of 2
It is necessary to keep it about double. Further, it goes without saying that the present invention can be applied to not only a wiggler but also other types of insertion light sources such as an undulator.

[0020]

As described above, in the insertion light source of the present invention, in addition to the wiggler coil for individually exciting each core of the electromagnet, the pertabeta coil for uniformly exciting each core is provided. Since it has a built-in configuration, it can be used as an insertion light source by energizing the wiggler coil in normal times, and it can also be easily switched to a pertabeta by energizing the pertabeta coil when entering charged particles. Therefore, by adopting the insertion light source of the present invention, it is possible to omit the perturber which has been indispensable in the past, and as a result, when both the insertion light source and the pertabeta are installed separately. Compared to the above, it has the effect of significantly saving the installation space, and it seems that it is impossible to secure a sufficient straight part for the storage ring It is particularly suitable to adopt the type of particle accelerator.

[Brief description of drawings]

FIG. 1 is a plan view showing a schematic configuration of a wiggler which is an embodiment of the present invention.

FIG. 2 is a front sectional view of the wiggler.

FIG. 3 is a plan view showing a schematic configuration of a wiggler which is another embodiment of the present invention.

FIG. 4 is a diagram showing an outline of a synchrotron.

FIG. 5 is a front sectional view showing a schematic configuration of a pertabeta in the synchrotron.

FIG. 6 is a side view showing a schematic configuration of a conventional general wiggler.

[Explanation of symbols]

 5 Storage ring 30 Electromagnet 31 Core 32 Wiggler coil 35 Pertabeta coil 37 Pulse power supply

Claims (1)

[Claims] 1. A large number of electromagnets whose polarities change periodically are arranged side by side in the length direction of the storage ring on the outer side of the linear portion of the storage ring in a particle accelerator such as a synchrotron, and the storage ring is generated by the magnetic force of the electromagnets. An inserted light source such as a wiggler configured to deflect charged particles passing through the inside to extract emitted light, wherein each electromagnet includes a core surrounding a storage ring and each core for individually exciting each core. And a perturbator for constructing a perturbator by uniformly exciting each core provided on both sides of the storage ring so as to penetrate through the core. Insertion light source in a particle accelerator, characterized in that it comprises a coil.