JPH02120688A - Method for detecting electron beam of electron accumulation ring - Google Patents

Abstract

PURPOSE:To certainly detect electron beam by providing a notch part to a vacuum duct wherein electron beam goes around and hermetically closing said notch part by an airtight chamber having an observation window. CONSTITUTION:A drive shaft 26b is moved downwardly and a fluorescent plate 25 is positioned so as to cross an electron beam track in a notch part 22. Electron is incident to an accumulation ring from an incident part. Whereupon, the electron beam goes around at a predetermined angle in the ring to be incident to the fluorescent plate 25 and makes the electron incident position on the fluorescent plate bright. By observing this position from an observation window 23 by a monitor device such as television camera, the passing position of electron beam in the cross-section of the vacuum duct can be directly observed. A deflection electromagnet or converging electromagnet is adjusted so that electron passes through a predetermined track in a predetermined beam diameter while the electron beam is confirmed by said observation. Since this adjustment is performed while the cross-sectional shape or position of the electron beam is directly observed, said adjustment can be easily performed within a short time.

Description

[Detailed description of the invention] [Summary] Synchrotron orbital synchrotron radiation (Synchrotron radiation) used as an X-ray source in X-ray phosphorography
Regarding the detection method for detecting the position of the electron beam in a vacuum duct in an electron storage ring that emits a In order to facilitate orbit adjustment, shorten the beam launch time, and improve the operation rate of the storage ring, a cutout is provided in the vacuum duct in which the electron beam circulates, and the cutout is used as an observation window. A fluorescent plate that emits light with an electron beam and a lid member having a cavity having the same cross section as the inner wall of the vacuum duct are movably provided in the airtight chamber, and when the electron beam is started, the fluorescent plate is The lid member is inserted into the notch so as to intersect with the electron beam, and the position of the electron beam is observed through the observation window, and during operation, the lid member is moved so that the cavity is continuous with the inner wall of the vacuum duct, and the notch is closed. It has a covering structure.

(Industrial Application Field) The present invention relates to synchrotron orbital synchrotron radiation (SynchrotronR) used as an X&% source in X-ray lithography.
The present invention relates to a detection method for detecting the position of an electron beam within a vacuum duct in an electron storage ring that emits radiation (hereinafter abbreviated as SR).

In recent years, as the density of semiconductor integrated circuits has increased, patterning has become finer in the submicron range, and X-ray transfer methods using X-rays as a light source have been in the spotlight. That is, X
This is because the wavelength of the rays is orders of magnitude shorter than that of conventional ultraviolet rays, and scattering within the substrate or resist film is small, making it possible to form finer, more precise patterns.

Since SOR has a powerful beam and extremely small spread, it is ideal as an X-ray source for this purpose, and various electron storage rings have been developed as SOR light sources.

[Prior Art] An electron storage ring is an ultra-high vacuum annular duct in which various electromagnets and acceleration cavities for controlling electron beams are arranged in orbit. The electron beam is accelerated while circulating within this storage ring, and when the electron beam is deflected at the position of a deflection electromagnet provided in the ring, an SR containing an X-ray wavelength is emitted.

The outline of the electron storage ring will be explained with reference to FIG.

Electrons that have been preliminarily accelerated by an input accelerator 11 configured with a linear accelerator or the like are input into a storage ring 13 from an input section 12 .

The storage ring 13 includes an ultra-high vacuum duct made of an annular hollow pipe of a conductor, and a plurality of bending electromagnets 1 around it.
4, a high frequency acceleration cavity 15, a beam line 16, etc. are arranged.

The electrons incident from the incidence part 12 are transmitted to a plurality of bending electromagnets 1.
4, the electron orbits within the storage ring 13, and is accelerated to a predetermined level by the high-frequency acceleration cavity 15, whose frequency is synchronized with one cycle of the electrons.

When the electrons orbit within the storage ring 13 hundreds of thousands of times and reach a predetermined energy and the electron beam rises, the storage ring 1
Radiant light 17 is extracted from a beam line 16 located at 3.

In order for the electrons injected into the ring to be controlled by electromagnets and accelerators and repeat several hundred thousand orbits, they must first travel the correct trajectory within the vacuum duct during the -th orbit.

[Problem to be solved by the invention] Conventionally, the observation of the electron beam position within the storage ring was performed by observing the synchrotron radiation after the electron beam rises (that is, after the electrons repeat orbits and are accelerated to a predetermined energy). However, it was not possible to detect whether the beam had passed through the correct position in the vacuum duct during its first orbit.

Therefore, when starting up the beam for the first time after disassembling and reassembling the device for repair, maintenance, modification, etc., the beam was started up by trial and error while making fine adjustments to the deflection magnets and acceleration cavities.

For this reason, there was a problem in that it took a long time to start up the beam, and the operating rate of the storage ring decreased.

The present invention was created in view of the above problems, and by installing a fluorescent plate detector inside the storage ring and directly detecting the electron beam image, it is possible to easily adjust the trajectory and shorten the beam startup time. The purpose is to improve the operating rate of

[Means for Solving the Problems] FIG. 1 shows a diagram for explaining the principle of the detection method of the present invention.
This is a schematic cross-sectional view of the beam detection section of the electron storage ring viewed from above.
b) shows when the storage ring is in operation.

In order to solve the above-mentioned conventional problems, the electron beam detection method for an electron storage ring according to the present invention, as shown in FIG.
A notch 22 is provided in the holder, and the notch 22 is sealed with an airtight chamber 24 having an observation window 23. Inside the airtight chamber 24, a fluorescent screen 25 that emits light with an electron beam and a vacuum duct (21a, 21b) having the same cross-section as the inner walls of 21a and 21b are provided. A cover member 26 having a cavity 26a is movably provided, and when starting up the electron beam, the fluorescent plate 25 is inserted into the notch 22 so as to intersect with the electron beam, and the position of the electron beam is monitored through the observation window 23. observe,
During operation, the cavity 26a becomes a vacuum duct) 21a, 21b.
In this method, the lid member 26 is moved so as to be continuous with the inner wall of the notch 22.

[Effect]

At the time of beam startup, the fluorescent screen 25 is positioned so as to intersect the electron beam trajectory, and accelerated electrons are incident on the ring from the incidence section. Then, during the first rotation, the electron beam enters the fluorescent screen as shown by arrow A, causing the electron incident value iP on the fluorescent screen 25 to shine. This position is indicated by arrow B through the observation window 23.
By observing with a monitor device such as a television camera, it is possible to directly observe the position of the electron beam within the cross section of the X-air duct. It is extremely easy to adjust the deflecting electromagnets and focusing electromagnets so that the electrons are positioned in a predetermined orbit while confirming this observation, and the adjustment time can be shortened.

Incidentally, in order for the electron beam to continue circulating stably, it is necessary that the cross section of the vacuum duct be uniform and continuous over the entire circumference of the vacuum duct. In other words, if there is a discontinuity on the wall of the vacuum duct, the electromagnetic field (wake field) induced on the inner wall of the vacuum duct by the preceding electron beam will exert a force on the subsequent beam, causing the beam's trajectory to gradually deviate from its normal position and become uncontrollable. There is a problem that the electron storage life is shortened.

In the above observation state, the inner wall of the vacuum duct becomes discontinuous with other parts in the detection unit due to the observation window, fluorescent screen holding mechanism, etc., and a wake field is generated, but the orbit deviation per orbit due to this is extremely small, so the observation The effect on the value is negligible.

During operation after the above adjustment is completed, the fluorescent screen 25 is retracted from the electron orbit and the lid member 26
into the notch 22 of the vacuum duct and fill the cavity 26a.
Connect the vacuum duct with. As a result, the cross section of the vacuum duct becomes continuous at the detection part, and no wake field is generated. Therefore, when electrons are properly injected, they normally pass through the detection section as shown by arrow C, and since the deflection system is properly adjusted, the incident electrons repeat the circuits correctly and a high-speed electron beam is raised and the device is in operation.

〔Example] The present invention will be explained in detail below with reference to the accompanying drawings.

FIG. 10 is a diagram showing an embodiment of the detection method of the present invention.

The figure shows an electron beam detection section, which is installed on a part of the circumference of the annular vacuum duct of the electron storage ring shown in FIG.

In the figure, 21a and 21b are vacuum ducts made of metal materials, through which the electron beam e- travels.

The vacuum ducts 21a and 21b are provided with a notch 22 for inserting a fluorescent screen 25 into the electron beam orbit.

Reference numeral 24 denotes an airtight chamber, which is arranged to surround the notch 22 of the vacuum duct, and is maintained at the same degree of vacuum as the vacuum duct. An observation window 23 made of glass or the like is provided so that the notch 22 can be observed from the outside.

Reference numeral 25 denotes a fluorescent plate that emits light upon collision with an electron beam, and is connected to the top of the lid member 26 by a shaft 25a at an angle of 45 degrees with respect to the axial direction of the vacuum ducts h21a and 21b. Lid member 2
6 is made of a conductive material with the same length as the notch 22 of the vacuum duct, has a cavity 26a with the same cross section as the inner wall of the vacuum duct, and is driven by a drive shaft 26b passing through the bellows part 24b of the airtight chamber 24 in a vacuum-sealed manner. It is disposed within the airtight chamber 24 so as to be movable up and down.

Detection of an electron beam is performed as follows using the detection section having the above configuration.

First, the drive shaft 26b is moved downward to position the fluorescent screen 25 within the notch 22 of the vacuum duct so as to intersect the electron beam trajectory. (The figure shows this state.) Electrons are then injected into the storage ring from an input section (not shown). The electron beam then travels around the ring at a predetermined angle and then enters the fluorescent screen 25, illuminating the electron incident position on the fluorescent screen. By observing this position through the observation window 23 with a monitor device such as a television camera, it is possible to directly observe the passage position of the electron beam within the cross section of the vacuum duct.

While checking this observation, the deflection electromagnet and focusing electromagnet are adjusted so that the electrons pass through the specified trajectory with the specified beam diameter.

Since this adjustment can be performed while directly observing the cross-sectional shape and position of the electron beam, it can be easily performed in a short time.

During operation after the above adjustment is completed, when the drive shaft 26b is moved upward, the fluorescent screen 25 is retracted from the electron orbit and the lid member 25 is moved to the position of the notch 22 of the vacuum duct, thereby opening the cavity. Vacuum duct by 26a) 2
The inner walls of 1a and 21b are connected, and the cross section of the vacuum duct becomes continuous. Therefore, in the electron storage ring, the electron beam stably passes through the detection section without causing a dropout in the beam detection section.

[Effects of the Invention] As described above, according to the beam detection method of the present invention, an electron beam can be reliably detected by a fluorescent screen without generating a wake field that adversely affects the electron beam. It is remarkable that the beam start-up and adjustment time can be shortened, contributing to an improvement in the operating rate of the device.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram showing the detection method of the present invention, and FIG. 2 is a diagram showing the principle of the detection method of the present invention.
FIG. 3 is a diagram showing an embodiment of the present invention. FIG. 3 is a diagram showing the configuration of an electron storage ring. In the figure, 21a, 21b - Vacuum duct, 22 - Notch of vacuum duct, 23 - Observation window, 24 - Airtight chamber, 25 - Fluorescent screen, 26 - Lid member, 26a - Cavity of lid member, 26b - Drive shaft , is. (!2) Den+Runmu/17 Houshiki
(No. 1) - Six!
Did you leave the house? Is it possible to show a thousand miles diagram S? Shown, not shown

Claims (1)

[Claims] A method for detecting the position of an electron beam in a vacuum duct of an electron storage ring, comprising: a vacuum duct (21a, 21
b) is provided with a cutout (22), the cutout (22) is sealed with an airtight chamber (24) having an observation window (23), and a fluorescent screen (25) that emits light with an electron beam is placed inside the airtight chamber (24). )and,
A lid member (26) having a cavity (26a) having the same cross section as the inner wall of the vacuum duct (21a, 21b) is movably provided, and when starting up the electron beam, the fluorescent plate (25) is inserted into the notch (22). The position of the electron beam is observed through the observation window (23) by inserting the cavity (26a) into the vacuum duct (21) so as to intersect with the electron beam.
a, 21b) so as to be continuous with the inner wall of the lid member (26).
) to cover the notch (22).