JPH0817599A - Vacuum sealed and inserted light source - Google Patents

Abstract

PURPOSE:To make a vacuum vessel very compact, compared with the case of a conventional inserted light source, by providing the vacuum vessel between the opposite faces of two magnet holders, regarding the vacuum sealed and inserted light source. CONSTITUTION:Linear guides 8 are laid on a rack 9 in a right and left direction, and sliders 20 are slidably mounted on each guide 8. Also, magnet holders 2 are laid on each slider 20, so as to be faced to each other. The holders 2 are provided with a plurality of opposed magnets 3, thereby forming periodical magnetic field as an inserted light source. Also, supports 7 are erected on each slider 20 respectively at the back of the holders 2 and a rod 6 is provided between the support 7 and the holder 2. As a result, an interval between the holders 2 can be changed and the intensity of the periodic magnetic field as the inserted light source can be adjusted by causing the slider 20 to travel along the guide. According to this construction, a vacuum vessel can be made very compact, compared with the case of a conventional inserted light source.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a vacuum sealed insertion light source. For example, the present invention relates to a wiggler or undulator that applies a periodic magnetic field to an electron beam or a positron beam in order to generate laser light or synchrotron radiation with a synchrotron or a linear accelerator.

[0002]

2. Description of the Related Art As shown in FIG. 6, when a high-energy electron beam 010 is caused to meander in a periodic magnetic field between magnets 03, it is known that radiant light with high directivity and high brightness can be obtained. Has been. The device for obtaining such emitted light is the insertion light source 013, and depending on the strength and application of the magnetic field, a wiggler (strong magnetic field type) or an undulator (weak magnetic field type).
is called.

As shown in FIG. 5, a resonator 014 is arranged before and after the insertion light source 013, an electron beam 010 is made incident on the insertion light source 013 from an electron accelerator 012, and the emitted light generated by the insertion light source 013 is resonated. A free electron laser 015 is a laser that causes the radiated light to resonate with the electron beam 010 that is successively incident by being reflected by 014. In the drawing, 016 indicates a beam dump. One of the conditions for satisfying this resonance condition is the magnetic field intensity of the insertion light source 013. This magnetic field strength is set by adjusting the interval, that is, the gap, between the magnets 03 mounted in the insertion light source 013 and facing each other.

Here, if the magnet period 018 (= λ _w ) is shortened, the central magnetic field of the insertion light source 013 is lowered. On the other hand, the oscillation wavelength of the free electron laser 015 is
Since it becomes shorter in proportion to 8, a short wavelength free electron laser 0
In order to obtain 15, the magnet period 018 is inevitably shortened, the central magnetic field is lowered, the resonance condition is not satisfied, and it becomes difficult to oscillate the free electron laser 015. Therefore, as shown in FIG. 6, in the insertion light source 013 of the related art, a beam duct 017 for creating a vacuum atmosphere is provided between opposing magnets 03, and the electron beam 010 is propagated in the beam duct 017. Since the duct 017 interferes, it cannot be set below a certain gap.

Therefore, in the prior art, in order to make the gap of the magnet 03 as small as possible, instead of the beam duct 017, as shown in FIG.
Further, as shown in FIG. 4, the magnet 03 and the magnet holder 02 themselves are covered with the vacuum container 011. This is called a vacuum sealed insertion light source. That is, as shown in both figures, a vacuum container 011 is placed on a pedestal 09 made of die steel, and the magnets 03 facing each other in the vacuum container 011 are fixed to the magnet holders 02, respectively. The magnet holder 02 is connected to each rod 06, and each rod 06 is hermetically penetrated through the vacuum container 011 via a bellows 019 and supported by a support 07 in the atmosphere.

Therefore, in the vacuum-sealed insertion light source having the above structure, the magnets 03 face each other in the vacuum atmosphere of the vacuum container 011 and the beam duct 017 does not exist between these magnets 03, so that the space between the magnets 03 is reduced. The gap can be minimized.

[0007]

However, in the above-mentioned conventional vacuum-sealed insertion light source, the magnet 03, the magnet holder 02, etc., which are the main components of the insertion light source 013, are covered with the vacuum container 011. Has the drawback of being very large. Therefore, there is a problem that the installation adjustment time increases due to the difficulty of handling the insertion light source 013 and the experiment time of the oscillation experiment of the free electron laser 015 increases due to the difficulty of alignment, and the manufacturing cost of the insertion light source 013 also increases. The electronic laser 015 is a hindrance to industrial application.

The homogeneity of the magnetic field strength is one of the oscillation conditions of the free electron laser 015, and is designed and manufactured so that the variation of the magnetic average strength among the magnets 03 is suppressed within 0.1%. Has been done. Therefore, as the insertion light source 013, the gap of the magnets 03 is adjusted to drive the homogeneity of the magnetic field strength in order to achieve the homogeneity of the magnetic field strength of each of the aligned magnets 03, but the expected gap is obtained. There was no problem.

That is, in the conventional vacuum-sealed insertion light source, the magnet 03 and the magnet holder 2 are incorporated into the vacuum container 011 after the gap is adjusted outside the vacuum container 011.
Since an assembly error will occur during assembly, the gap with adjusted bending angle cannot be obtained as expected. The present invention has been made in view of the above prior art, and an object of the present invention is to provide a vacuum-sealed insertion light source that can be downsized and that can easily adjust the uniformity of magnet strength. .

[0010]

The structure of the present invention which achieves the above object has two or more magnets arranged in a predetermined magnetization direction.
In a device which is arranged horizontally in a row, generates a periodic magnetic field between the magnet rows, and causes the electron beam incident between the magnet rows to meander to radiate the electromagnetic waves, a magnet holder for holding the magnets is provided. The opposing surfaces are joined by a vacuum container that covers the magnet, and an expandable bellows is provided in the vacuum container. The magnet is inserted into the front surface of the magnet holder in a positionally adjustable manner, and a rear flange is detachably provided on the back surface of the magnet holder. The bellows are rectangular or racetrack-shaped. It is characterized by that.

[0011]

In the vacuum sealed insertion light source, since the vacuum container is provided between the surfaces of the two magnet holders facing each other, the vacuum container can be made very compact as compared with the conventional insertion light source. Further, since the vacuum container is provided with the expandable bellows, it is possible to adjust the gap between the magnets by adjusting the gap between the magnet holders while maintaining the vacuum atmosphere.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. A vacuum sealed insertion light source according to an embodiment of the present invention is shown in FIGS. As shown in both figures, the linear guides 8 are arranged on the gantry 9 in the left-right direction, the sliders 20 are slidably mounted on the respective linear guides 8, and the magnet holders 2 are mounted on the sliders 20 respectively. It is installed facing each other.

A plurality of opposing magnets 3 are arranged in the magnet holder 2 as will be described later so that a periodic magnetic field as an insertion light source is achieved. In addition, a support 7 is provided upright on the rear of the magnet holder 2 in each slider 20, and a rod 6 is interposed between the support 7 and the magnet holder 2. Therefore, by sliding each slider 20 along the linear guide 8, it is possible to change the interval between the magnet holders 2 and adjust the intensity of the periodic magnetic field as the insertion light source. In addition, the moment due to the attraction force between the magnets generated by the magnet 3 is
Via support 7, slider 20 and linear guide 8
Can be received at.

Further, a vacuum container 1 surrounding the magnet 3 is airtightly joined between the opposing surfaces of the magnet holder 2, and the vacuum container 1 is provided with an expandable bellows. Therefore, the magnet 3 is kept in a vacuum atmosphere in the vacuum container 1, and the bellows freely expands and contracts even if the distance between the magnet holders 2 is adjusted, so that the magnet 3 is kept in the vacuum atmosphere. The gap 4 can be adjusted.
Although a rectangular bellows is provided in this embodiment, a racetrack-shaped bellows may be provided instead of this.

In the front-rear direction of the vacuum container 1, vacuum container flanges 1a shown in FIG. 2 are provided, respectively. These vacuum container flanges 1a are connected to a vacuum duct which is a beam transport system of the free electron laser device. As the vacuum container flange 1a, for example, a conflat flange or the like is used. Therefore, the free electron laser 10 from the free electron laser device enters the vacuum container 1, receives the periodic magnetic field by the magnet 3 in the vacuum atmosphere of the vacuum container 1, and emits in a meandering motion.

On the other hand, a plurality of slit-shaped notches 2a are provided on the front surface of each magnet holder 2 by machining or the like, and a magnet 3 and an iron core or a ferromagnetic material are inserted into these notches 2a. Here, the magnet 3 is inserted into the notch 2a of the magnet holder 2 in consideration of the magnetization direction. Notch 2
The number of a is the same as the number of the magnet 3 and the iron core or the ferromagnetic material to be inserted. A back flange 5 is detachably attached to the back of each magnet holder 2. Since the rear surface flange 5 is airtightly fitted to the magnet holder 2,
The vacuum atmosphere in the vacuum container 1 can be maintained.

When the magnet holder 2 is detached from the rear flange 5, the magnet 3 can be pushed and pulled from the rear surface. Therefore, even after the apparatus is assembled, the gap between the magnets 3, that is, The magnetic field strength at the center of the insertion light source can be made variable. Further, by attaching an iron shim or the like to the back surface of the magnet 3, the magnetic field strength can be similarly changed. Therefore, it is possible to easily improve the homogeneity of the magnetic field with high accuracy. A non-magnetic and rigid material is used for the magnet holder 2. For example, SUS3
16 can be used.

In the vacuum-sealed insertion light source of the present embodiment having the above-mentioned structure, since the vacuum container 1 covering the magnet 3 is provided between the facing surfaces of the magnet holders 2 facing each other, the insertion light source can be made extremely small. be able to. Therefore, the cost of the apparatus main body can be reduced, and the labor required for handling and installation and adjustment of the apparatus can be reduced, and the free electron laser can be promoted for industrial use. Further, since the vacuum container 1 is provided with a bellows that can expand and contract, the slider 20 is slid along the linear guide 8 while the vacuum container 1 is kept in a vacuum atmosphere.
Can be adjusted to adjust the magnetic field strength of the insertion light source, that is, the gap 4.

Furthermore, since the back surface flange 5 is detachably attached to the back surface of the magnet holder 2, the back surface flange 5 is removed and the magnet 3 is pushed and pulled even after the insertion light source is assembled. The strength of the magnetic field of the insertion light source can be adjusted. Therefore, it is possible to adjust the variation of the gap 4 due to the assembly error, that is, the variation of the magnetic field homogeneity with a small labor, and it is possible to manufacture a high-performance vacuum sealed insertion light source.

[0020]

As described above in detail with reference to the embodiments, according to the present invention, in the vacuum-sealed insertion light source, the vacuum container is provided between the opposing surfaces of the two magnet holders. Therefore, the vacuum container can be made very compact as compared with the conventional insertion light source. Further, since the vacuum container is provided with the expandable bellows, it is possible to adjust the gap between the magnets by adjusting the gap between the magnet holders while maintaining the vacuum atmosphere.

[Brief description of drawings]

FIG. 1 is a front view of a vacuum-sealed insertion light source according to an embodiment of the present invention.

FIG. 2 is a plan view of a vacuum sealed insertion light source according to an embodiment of the present invention.

FIG. 3 is a front view of a conventional vacuum sealed insertion light source.

FIG. 4 is a side view of a conventional vacuum sealed insertion light source.

FIG. 5 is an explanatory diagram showing the oscillation principle of a free electron laser.

FIG. 6 is a bird's-eye view of a conventional insertion light source.

[Explanation of symbols]

 1 Vacuum container with bellows 2 Magnet holder 3 Magnet 4 Gap 5 Rear flange 6 Rod 7 Support 8 Linear guide 9 Stand 10 Electron beam 20 Slider

Claims (1)

[Claims] 1. A plurality of magnets are horizontally arranged in two rows with a predetermined magnetization direction, a periodic magnetic field is generated between the magnet rows, and an electron beam incident between the magnet rows is caused to meander. In the device for radiating the electromagnetic wave, the opposing surfaces of the magnet holder for holding the magnet are joined by a vacuum container covering the magnet, and an expandable bellows is provided in the vacuum container. Vacuum sealed insertion light source.