JPH03179700A - Storing ring system, industrial light radiation apparatus and acceleration system - Google Patents

Abstract

PURPOSE:To reduce the size and simplify the constitution of a storing ring system by using a wake field accelerator as an incident device to a radiated light generating part. CONSTITUTION:A wake convergence type electronic storing ring 100 is composed of a deflection magnet 104, high frequency acceleration hollow body 101, pertabeta 102, vacuum duct 103, radiated light beam line 110 and the like, wherein a wake field accelerator 50 is used as the incident device of week convergence type electronic storing ring 100. In this case, high energy electrons from the accelerator 50 are stored in the duct 103 and capable of being incident through acceleration of the electrons to the last energy. No acceleration is therefore required in the ring 100. Since the magnitude of the deflection field caused by the magnet 104 may be constant accordingly, the whole configuration of the system including the power supply thereof is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an accelerator system using a wake field accelerator as an injector, which is a high electric field type linear accelerator suitable for downsizing the entire accelerator.

[Conventional technology]

Conventionally, there are the following three types of storage ring systems for accelerating and storing electron beams. Figure 7 shows these three systems. The first system is a system consisting of a linear accelerator 501 and a storage ring 502. linear accelerator 5
01, the energy is accelerated to the final energy, and the energy is stored in the storage ring 502 without being accelerated within the ring. Although this system has a large accumulated current value, it has the disadvantage that the linear accelerator 501 is too long. The second system consists of a linear accelerator 501, a synchrotron 503, and a storage ring 502. In this system, the electrons are accelerated to the speed of light in a linear accelerator 501 and then implanted into a synchrotron 503. The synchrotron 503 accelerates the electrons to the final energy and stores the implanted electrons in a storage ring 502. This system also becomes larger and more complex as a whole.6 In the third system, charged particles are input from a linear accelerator 501 into a storage ring 502 and are also accelerated within the storage ring 502.

Since this system is accelerated by the storage ring 502, it is smaller than the two systems described above, but the entire system is still huge.

[Problem to be solved by the invention]

As described above, conventional storage ring systems have become larger and more complex.

The purpose of the invention is to miniaturize and simplify storage ring systems.

[Means to solve the problem]

In order to achieve the above object, in the first system described in the prior art, the acceleration gradient of the linear accelerator is increased and the length of the linear accelerator is shortened.

An example of a means for increasing the acceleration gradient of a linear accelerator is a wake field accelerator. This uses large current of electrons,
A wake field (an unsteady electromagnetic field left by electrons in the acceleration tube) is accumulated in the linear accelerator tube, and the electric field generated by the large high-frequency electromagnetic field is used to accelerate the small current of electrons that enter later.

In this wake field accelerator, the current of the electron group is controlled so that most of the large current electron group that excites the wake field are uniformly decelerated by the self-induced wake field.

In order for the charged particles to be accelerated to be accelerated by the excited wake field, after the charged particle beam that excites the wake field has passed, the period 174 determined by the resonance angular frequency of the fundamental mode of the cavity must be Alternatively, the accelerated charged particle group is made to follow the accelerated charged particle group after a time period which is a positive integer multiple of the period.

In order for the charged particles that excite the wake field to receive a −-like deceleration voltage, the current of the charged particles that excites the wake field is increased steeply at first, and then the amount of increase is One possible method is to control the current waveform so that it becomes slow.

In addition, there is a method in which the current waveform of a group of charged particles is made into an exponentially saturated type. For example, there is a method in which the current generated by a group of charged particles that excites the wake field is changed over time as shown in (1).

where IO is a constant, ω is the resonant angular frequency of the fundamental mode of the cavity, and γ
is the attenuation factor based on the finite conductivity of the cavity.

[Effect]

A wake field accelerator will be explained using the example of the above equation (1) as an example of means for the operation of the present invention.

The acceleration voltage on the cavity center axis due to the wake field excited in the above case is expressed as V (t) using a time-varying complex representation of e in the fundamental mode jωt-mode approximation of the resonance angular frequency ω. Then, V(t)=-2RIov(t) ”'(2
) Here, γ 1 ω 2Q Q can be expressed as the Q value of two cavities. The actual acceleration voltage V (t) is the real part of the complex representation acceleration voltage V (t) shown in equation (2). FIG. 1 shows how the accelerating voltage V (t) changes over time.

As this figure shows, when O≦t≦T, v(t) takes a constant negative value, and the group of electrons making up the current I(t) receives a constant deceleration voltage while exciting the wake field. become. Therefore, the energy conversion efficiency at this time is approximately 100% at T)-, and this value does not change even if T is large, where ω T>1/γ. The boost ratio R is n
= γT, approximately R = 20 (1-e-m) ・= (3
).

In such a wake field accelerator, the energy conversion efficiency is 100% and the boost ratio is as high as about 2Q (=10'), so
With a current of several tens of kiloamps, an accelerator with an ultra-high electric field of IG e V / m class is possible, which is 1/1 the size of the current linear accelerator.
There is an effect that the size can be reduced to 0.00.

[Example] First, an example of a wake field accelerator as an example of the present invention will be described. One embodiment thereof will be explained with reference to FIG.

An electron gun 1 equipped with a cathode electrode 12, a grid electrode 10 for current control, and a cavity 2 where a wake field is generated.
, a converging coil 3 for converging an electron beam, an electron beam collector 4, a deflection magnet 5, and a high-energy electron extraction boat 6. Further, the grid electrode 10 provided in the electron gun 1 has a grid voltage control port J.
lll is attached. Based on the above configuration, the operation of this embodiment will be explained.

The amount of electrons generated from the cathode electrode 12 maintained at a negative high voltage is controlled by the electric field generated by the grid electrode 10. This can be performed by controlling the potential of the grid electrode 10 using the grid voltage control circuit 11. At this time, the current 1 (t) is made to comply with equation (7). This generates an electron beam 20 that excites the wake field. At this time, a magnetic field is generated in the axial direction of the cavity 2 from beginning to end by the converging coil 3 so that the electron beam 20 does not become unstable. In order for the group of accelerated electrons to be accelerated by the excited wake field, the electron beam 2
0 on the axis of the cavity 2, the electron group 2 is accelerated.
1 is fired after a certain amount of time. At this time, the acceleration is 2 π
It is better to set the length C of the group of electrons 21 to be sufficiently shorter than ω as the speed of light. Furthermore, it is better to take the positive integer N in equation (4) as small as possible.

This is because if N is too large, the risk of discharge due to the intense high-frequency electric field caused by the wake field increases.

The electron beam 20 that has excited the wake field has its trajectory bent by the magnetic field of the deflection magnet 5 and is taken into the collector 4 . On the other hand, the electron group 21 accelerated to high energy by the high voltage of the wake field is less affected by the magnetic field of the deflection magnet 5, and is guided toward the extraction boat 6 and provided to the user.

According to this embodiment, the three-dimensional circuit represented by the high-frequency oscillator tube and related power supply and waveguide, which were conventionally required, is no longer necessary, and the effect is that high-energy electrons can be generated with an extremely small and inexpensive device. There is.

Another embodiment of the invention is shown in FIG. In addition to the basic configuration shown in FIG. 2, a laser 30 and a mirror 31 are added. In this example, the initial time of the beam current waveform @T/
The constant component of 4 and the accelerated electron beam are generated by photoelectrons from a laser, and most of the other current is the amount of electrons generated from the cathode electrode 12 kept at a negative high voltage by the grid electrode 10. Controlled by the potential of

By dividing the functions between the laser 30 and the grid electrode 12 in this way, it is possible to provide high functionality of both high-speed switching using the laser and large current control using the grid electrode.

In the embodiment shown above, high-energy electrons can be generated,
Since this is separated by a deflection magnet and provided to the user, by applying the present invention to an industrial synchrotron radiation device, the industrial synchrotron radiation device can be significantly downsized. That is, it is shown as system 3. Since the linear accelerator can be significantly downsized, the system 3 can be further downsized. Furthermore, conventionally, electrons that have been accelerated to a certain level by a linear accelerator are accelerated to high energy by a synchrotron and then incident on an electron storage ring, but if the present invention is applied, the wake field accelerator of the present invention can be ,
Since high-energy electrons (electron storage ring) of 1 Gev can be input with a length of 1 m, a synchrotron function is not required for the electron storage ring, and the electron storage ring is simplified, making it suitable for industrial synchrotron radiation equipment. Devices such as these will be significantly miniaturized.

FIG. 4 shows an example in which the present invention is applied to a circular peel-off bundle type electron storage ring. The peelable bundle type electron storage ring 100 is as follows.

Deflection magnet 104, high frequency acceleration cavity 101, perturbator 102, vacuum duct 103, synchrotron radiation beam line 110
It is composed of etc. The figure shows the wake field accelerator 50 shown in FIG.
This figure shows an example in which it is used as an injector. Of course, the third
The wake field accelerator shown in the figure can also be used as an injector.

High-energy electrons incident from the wake field accelerator 50 are accumulated in the vacuum duct 103.

The perturbator 102 distorts the closed orbit within the ring so that electrons can easily enter the ring, and the high frequency acceleration cavity 101 accelerates the electrons to compensate for energy loss due to the generation of synchrotron radiation.

The synchrotron radiation is guided to the outside through a synchrotron radiation beam line 110 and is used for semiconductor exposure and the like.

According to this embodiment, since the wake field accelerator 50 can accelerate the electrons to the final energy before injecting them, there is no need for additional acceleration (synchrotron acceleration) in the electron storage ring. Therefore, the strength of the deflecting magnetic field generated by the deflecting magnet 104 may be constant. This has the effect of simplifying the configuration of the entire accelerator system including the power supply.

A racetrack type electron storage ring can have a similar effect instead of a peelable bundle type electron storage ring.

An example thereof is shown in FIG. The racetrack type electron storage ring 200 includes a deflection magnet 204 for deflecting electron trajectories and a quadrupole magnet 206 for converging an electron beam.
, a vacuum duct 203 for storing electrons, a high frequency acceleration cavity 201 for replenishing energy to electrons, an inflector 205 for guiding the incident electron beam to the ring, and a synchrotron radiation beam line 210 for guiding synchrotron radiation to the outside. It is composed of etc.

FIG. 6 shows an example of a method that does not store electrons.

High-energy electrons are accelerated to their final energy by the wake field accelerator 50, and their orbits are bent by the deflection magnet 304.
It passes through a vacuum duct 303 and is guided to the beam dump 4.

At this time, since the trajectory is bent, synchrotron radiation is generated, and the synchrotron radiation is led out through the synchrotron radiation beam line 310.

In this example, since the electrons pass through the vacuum duct 303 only once, there is an advantage that the precision of the magnetic field of the deflection magnet is low.

〔Effect of the invention〕

According to the invention, the storage ring system is miniaturized.

This has the effect of simplifying the process.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the basic phenomenon of the present invention, FIGS. 2 and 3 are diagrams showing a wake field accelerator suitable for the present invention, and FIG.
6 to 6 show an embodiment of the present invention, and FIG. 7 shows a conventional storage ring system. l...Electron gun, 2...Cavity, 3...Convergence coil,
4... Collector, 5... Deflection magnet, 6...
Take-out port, 7...4-pole magnet, 10...grid electrode, 11...grid voltage control circuit, 12...
...Cathode electrode, 13...Photocathode, 20...
- Electron beam, 21... Accelerated electron group, 30... Laser, 31... Reflection mirror, 40... Acceleration unit,
80... Cell, 81... Beam duct, 82...
Partition plate, 100... Peelable bundle type electronic storage ring, 20
0...Race track type electronic storage ring, 101,2
01...High frequency acceleration cavity, 102.202...Perturbator, 103,203°303...Vacuum duct,
104,204,304...Bending magnet, 110,21
0,310...Synchrotron radiation beam line, 501...Linear accelerator, 502...Electronic storage ω Tori 2-Zukougyuu~Eng 47B Todoroki Karo-k S. 1F Responsible Link (Q-) System 1 (b) Umatem 2 (() Womatem 3

Claims (1)

[Claims] 1. It has a cavity that excites the wake field, and the excited charged particle group that excites the wake field compensates for the Joule heat loss on the cavity wall surface caused by the wake field, resulting in almost constant deceleration. A wake field accelerator having a charged particle generator that generates a group of excited charged particles to receive a voltage, and then generates a group of accelerated charged particles that are accelerated by a wake field so as to follow the group of excited charged particles, and synchrotron radiation. A generating part,
An industrial synchrotron radiation device, characterized in that the wake field accelerator is used as an injector to the synchrotron radiation generating section. 2. It has a cavity that excites the wake field, generates a current formed by a group of excited charged particles that excites the wake field so that the energy accumulated in the wake field is directly proportional to time, and then follows the group of excited charged particles. a wake field accelerator having a charged particle generator that generates a group of accelerated charged particles that are accelerated by the wake field, and a synchrotron radiation generating section; An industrial synchrotron radiation device characterized by being a container. 3. It has a cavity that excites a wake field, and a group of excited charged particles that excites the wake field forms a current of several tens of KA, which is formed to compensate for Joule heat loss on the cavity wall surface caused by the wake field. By receiving a nearly constant deceleration voltage, a wake field accelerator with an ultra-high electric field of 1 Gev/m,
An industrial synchrotron radiation device, comprising: a synchrotron radiation generating section, and the wake field accelerator is used as an injector to the synchrotron radiation generating section. 4. The industrial synchrotron radiation device according to claim 1, 2 or 3, wherein the charged particles are electrons. 5. It has a cavity that excites the wake field, and is excited so that the excited charged particle group that excites the wake field compensates for the Joule heat loss on the cavity wall surface caused by the wake field and receives a nearly constant deceleration voltage. A wake field accelerator having a charged particle generator that generates a group of charged particles and then generates a group of accelerated charged particles that are accelerated by the wake field so as to follow the excited charged particle group, and at least a function of accumulating charged particles. A storage ring system comprising: a storage ring, the wake field accelerator serving as an injector to the storage ring. 6. It has a cavity that excites a wake field, and a group of excited charged particles that excites the wake field forms a current of several tens of KA, which is formed to compensate for Joule heat loss on the cavity wall surface caused by the wake field. By receiving a nearly constant deceleration voltage, a wake field accelerator with an ultra-high electric field of 1 Gev/m,
A storage ring system comprising at least a storage ring having a function of accumulating charged particles, the wake field accelerator serving as an injector into the storage ring. 7. The storage ring system according to claim 5 or 6, wherein the charged particles are electrons. 8. It has a cavity that excites a wake field, and a group of excited charged particles that excites the wake field forms a current of several tens of KA, which is formed to compensate for Joule heat loss on the cavity wall surface caused by the wake field. By receiving a nearly constant deceleration voltage, a wake field accelerator with an ultra-high electric field of 1 Gev/m,
An accelerator system comprising at least one bending electromagnet, the charged particles output from the wake field accelerator being incident on one end of the bending electromagnet. 9. The accelerator system according to claim 8, wherein the charged particles are electrons.