JPH05223997A - Irradiation window - Google Patents

Abstract

PURPOSE:To prevent the occurrence of creases on the surface of a window foil. CONSTITUTION:A window foil 1 is closely fitted to a window flange 2 by means of a retainer 4. During operation of an electron beam irradiating apparatus, the electron beam generating part is in a vacuum state, the window foil 1 comes into contact with a large number of water cooled crosspieces 6 set in the flange 2, and cooled. The end faces of the crosspieces 6 contacting with the window foil 1 are set by a distance (d) back from the foil-fitting plane of the flange 2 toward the inside of the irradiation window. Elongation of the foil during evacuation and its slack at the time of fitting the foil are absorbed by the step part of difference (d), and creases do not occur on the foil during evacuation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an irradiation window for cooling a window foil with a water cooling bar provided on a window flange.

[0002]

2. Description of the Related Art When an electron beam is taken out from an electron beam generator to an irradiation area, the inside of the electron beam generator is in a vacuum state and the irradiation area is in the atmosphere or an atmosphere of an inert gas. The inside of the electron beam generator is kept in a vacuum state by attaching a metal foil capable of transmitting the electron beam. 3 to 5 are configuration diagrams of an example of an irradiation window to which such a metal foil is attached, FIG. 3 is a front view seen from the irradiation region side, FIG. 4 is a sectional view taken along the line AA of FIG. FIG. 5 is a sectional view taken along line BB of FIG. A vacuum seal part having an O-ring 3 is formed on the window flange 2 provided on the electron beam extraction part and to which the metal foil, that is, the window foil 1 is attached, and the foil pressing plate 4 is fixed to the window flange 2 with the bolt 5. Thus, the window foil 1 is attached in close contact with the window flange 2.

When the electron beam passes through the window foil 1, a part of energy is lost and the window foil is heated. In order to prevent the window foil from being damaged by this heating, a large number of water cooling bars 6 are provided on the window flange 2. By flowing the cooling water through the refrigerant passage 7 formed inside the window flange 2,
The water cooling bar 6 is cooled. When the inside of the electron beam generator is evacuated, the window foil 1 comes into contact with the water cooling bars 6 and is cooled.

[0004]

As described above, when the window foil 1 is attached to the window flange 2 and the vacuum is applied, the window foil is stretched or slackened when the window foil is attached. As shown in FIG. 3, wrinkles 8 may occur. Since the wrinkles 8 do not contact the water cooling bars 6 as shown in FIG. 5, the wrinkles on the surface of the window foil lead to a reduction in the life of the window foil.

An object of the present invention is to provide an irradiation window that does not cause wrinkles on the window foil surface.

[0006]

The present invention has a water-cooling structure, and includes a window flange to which a window foil is attached, and a water-cooling bar provided on the window flange and contacting the window foil for cooling. In the irradiation window, the window foil contact end surface of the water cooling bar is located at a position retracted inward of the irradiation window from the window foil mounting plane of the window flange.

[0007]

[Function] Since the window end contact surface of the water-cooling bar is set back from the window foil attachment plane of the window flange to the inside of the irradiation window, the step of the contact edge face and the attachment plane stretches the window foil during vacuuming, Wrinkles do not occur on the window foil surface because the tarmi portion when the foil is attached is absorbed.

[0008]

An embodiment of the present invention will be described with reference to the drawings. 1 and 2 are cross-sectional views of the irradiation window corresponding to FIGS. 4 and 5 described above, and the same reference numerals as those in FIGS. 4 and 5 denote the same or corresponding portions. The water-cooling bar 6 is positioned so that the end of the water-cooling bar 6 on the irradiation region side, that is, the end face of the window foil contacting the window-foil-contacting end face is retracted by a distance d inward of the irradiation window from the window-foil mounting plane of the window flange 2. It is provided on the flange 2.

As described above, the surface of the window foil 1 in contact with the water-cooling bars 6 is made lower than the mounting surface of the window foil, so that the window foil stretches when the vacuum is drawn at this step portion, Talmi produced when the was attached to the window flange 2 was absorbed, and no wrinkles remained on the window foil surface when vacuuming was performed, and an irradiation window that does not cause wrinkles could be obtained.

[0010]

As described above, the present invention merely lowers the window foil contacting surface of the water cooling bar from the plane of the window flange on which the window flange is attached.
It is possible to configure an irradiation window that does not cause wrinkles on the surface of the window foil and can evenly contact the window foil with the water-cooling bars, and extend the life of the window foil.

[Brief description of drawings]

FIG. 1 is a cross-sectional view at a position parallel to a water cooling rail according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view at a position orthogonal to a water cooling rail.

FIG. 3 is a front view of a conventional irradiation window viewed from the irradiation area side.

FIG. 4 is a cross-sectional view at a position parallel to a water cooling rail.

FIG. 5 is a cross-sectional view at a position orthogonal to the water cooling rail.

[Explanation of symbols]

 1 Window foil 2 Window flange 4 Foil pressing plate 6 Water cooling bar 7 Refrigerant passage 8 Wrinkle d Water cooling bar retreat distance

Claims (1)

[Claims] 1. An irradiation window having a water-cooling structure, comprising a window flange to which a window foil is attached, and a water-cooling bar provided on the window flange for contacting and cooling the window foil. The irradiation window is characterized in that the window foil contact surface is located at a position retracted inward of the irradiation window from the window foil attachment plane of the window flange.