JP3580387B2 - Electron beam irradiation device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electron beam irradiation device.
[0002]
[Prior art]
It is already well known that a cathode is provided inside a vacuum chamber and an electron beam emitted from the cathode is irradiated from an irradiation window to the outside. This irradiation window is closed by a metal window foil. The window foil is cooled by spraying a cooling gas.
[0003]
Cooling gas supply pipes for supplying the cooling gas are provided on both sides of the irradiation window, and a cooling gas is blown from both sides of the window foil to cool the window foil. However, such a configuration requires two cooling gas supply pipes, which complicates the configuration. In order to avoid this, it is desirable to install the cooling gas supply pipe only on one side of the foil holding flange.
[0004]
FIG. 4 shows the conventional structure, wherein 1 is a vacuum chamber, 4 is a window provided at the lower part of the vacuum chamber 1, 3 is a window foil for closing an opening surface of the lower part of the window 4, and 5 is a window foil by the window 4. A foil holding flange 3 sandwiching and supporting the metal foil 3 is a metal seal for sealing between the window 4 and the window foil 3. The irradiation window 2 is constituted by the window 4, the window foil 3, the foil holding flange 5, and the like. Reference numeral 15 denotes a window bar for preventing the window foil 3 from expanding into the vacuum chamber 1 when the inside of the vacuum chamber 1 is evacuated. With respect to the heat generation of the window foil 3 caused by the passage of the electron beam, the cooling gas 9 from the cooling gas supply pipe 7 installed on one outside of the irradiation window 2 is directed toward the window foil 3 at the tip. The nozzle 8 is cooled by spraying it obliquely onto the window foil 3 with the nozzle 8.
[0005]
However, when the cooling gas 9 is sprayed obliquely upward from one side of the window foil 3 toward the window foil 3 as described above, the cooling gas 9 is reflected and scattered on the foil surface, and the flow of the cooling gas 9 on the foil surface is poor. This makes it difficult for the cooling gas 9 to reach the end of the window foil 3 on the side opposite to the spraying side, resulting in poor cooling efficiency. In order to compensate for the poor cooling efficiency, a large amount of cooling gas 9 needs to be flowed to reach the opposite end of the window foil 3. The cooling gas 9 in the cooling gas supply pipe 7 is sealed at a high pressure in a cooling gas tank (not shown), and the gas supply pipe 7 is connected to the tank by a connection pipe (not shown). Since the cooling gas 9 flows through the gas supply pipe 7 with a pressure difference from the atmospheric pressure, the pressure of the cooling gas 9 decreases in the flowing direction. Therefore, the blowing amount of the cooling gas 9 due to the pressure drop decreases along the length direction of the gas supply pipe 7. Therefore, there is a problem that the cooling efficiency is not constant at both ends of the window foil 3 along the length direction of the cooling gas supply pipe 7.
[0006]
[Problems to be solved by the invention]
In the present invention, when cooling the window foil of the irradiation window by spraying the cooling gas, reflection and scattering in the spraying direction of the cooling gas are eliminated, so that the cooling gas is uniformly flowed along the window foil, and the space of the pool is formed. It is an object of the present invention to make the amount of spraying the cooling gas uniform along the length direction of the cooling gas supply pipe by providing the cooling gas supply pipe.
[0007]
[Means for Solving the Problems]
The present invention provides a window provided at a lower portion of the vacuum chamber, a window foil for closing an opening surface of a lower portion of the window, and a foil holding flange for sandwiching the window foil between the windows. An electron beam irradiation apparatus comprising: an irradiation window serving as an electron beam extraction unit; and a cooling gas supply pipe for supplying a gas for cooling the window foil to one side edge of the irradiation window. A stagnant space for stagnating the gas supplied from the gas supply pipe inside the frame of the flange is provided, and at the inner upper end of the foil holding flange, between the inner lower end of the window, Providing a step portion forming a slit parallel to the window foil, the gas supplied from the drift space from the slit is parallel to the window foil. Characterized in that it comprises put come.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. The same reference numerals as in FIG. 4 indicate the same or corresponding portions. According to the present invention, a hole 11 for flowing a cooling gas from a gas supply pipe 7 is formed in the inside of one of the longitudinal frames 10 of the foil holding flange 5 from the outer surface thereof to the inside thereof. A plurality is provided in a line along the direction. A space in the pool for communicating with the plurality of holes 11 for uniforming the amount of cooling gas blown in the y-direction (which is a direction perpendicular to the electron beam), which is the length direction of the gas supply pipe 7. 12 is provided inside the foil holding flange 5. A step 16 provided at the upper end on the inner side of the frame 10 of the foil holding flange 5 faces the lower surface of the window foil 3 and is in parallel with the lower end on the inside of the window 4 so as to communicate with the space 12 in parallel. 13. The distance d is desirably about 1 mm or less.
[0009]
In the above configuration, the cooling gas 9 supplied from the cooling gas supply pipe 7 is supplied to the space 12 through the hole 11. Here, since the width of the slit 13 in the space 12 is narrow, the flow rate of the cooling gas 9 supplied from the gas supply pipe 7 through the hole 11 is smaller than the flow rate of the cooling gas 9 released from the slit 13. Become slow. Therefore, the cooling gas 9 stays in the space 12. The stagnated cooling gas 9 spreads in the y direction in the space 12, and the amount of the cooling gas 9 sprayed in the y direction becomes uniform. Therefore, the cooling gas 9 which can efficiently cool the window foil 3 in the y direction of the window foil 3 passes through the slit 13 and is blown out along the window foil 3 in parallel. The blown-out cooling gas flows from the end of the window foil on the side of the slit 13 to the opposite end along the foil surface. Therefore, in the x direction (which is also the width direction of the irradiation window 3) which is a direction orthogonal to the y direction of the window foil 3, the cooling gas 9 reflects and scatters on the window foil 3 as in the related art. Since it does not exist, it flows smoothly between both ends of the window foil 3, and the window foil 3 can be cooled efficiently.
[0010]
Since the window rail 15 is provided inside the window 4 as a window foil holder, the electron beam does not hit the window foil in contact with the lower part of the window rail 15. Therefore, the heating of the window foil in the portion where the window bar 15 is in contact is reduced, so that the cooling of the window foil only needs to be performed at the place where the electron beam is applied. For this reason, as shown in FIG. 3, a projection 17 is formed on the surface of the step 16 in accordance with the pitch of the window beam, and the lower surface of the window beam is placed at a position facing the projection 17 so that the electron beam strikes the window. Needless to say, a cooling gas may be supplied to only the foil.
[0011]
【The invention's effect】
As described above, according to the present invention, since the space of the pool where the gas supplied from the cooling gas supply pipe is stagnated is provided inside the foil holding flange, the window along the length direction of the cooling gas supply pipe efficiently. The foil can be cooled. Furthermore, since a slit is formed facing the window foil by providing a step at the upper end inside the foil holding flange so as to be parallel to the window foil, reflection and scattering of cooling gas on the foil surface are performed. And the effect of improving the efficiency of cooling the window foil can be achieved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an embodiment of the present invention. FIG. 2 is a detailed view of a foil holding flange of the present invention. FIG. 3 is a detailed view of a stepped portion of the foil holding flange of the present invention processed into a rectangular shape. 4 Configuration of conventional example [Explanation of reference numerals]
REFERENCE SIGNS LIST 1 vacuum chamber 2 irradiation window 3 window foil 4 window 5 foil holding flange 7 cooling gas supply pipe 9 cooling gas 10 frame 12 pool space 13 slit 16 step

Claims (1)

A window provided at the lower part of the vacuum chamber, a window foil for closing an opening surface of the lower part of the window, and a foil holding flange for sandwiching the window foil between the windows are used to extract an electron beam from the vacuum chamber. In an electron beam irradiation apparatus comprising a certain irradiation window, provided with a cooling gas supply pipe to which a gas for cooling the window foil is supplied to one side edge of the irradiation window, the inside of a frame of the foil holding flange is provided. In order to stagnate the cooling gas supplied from the cooling gas supply pipe through holes provided in a plurality of rows along the length direction of the frame , a space for a pool is provided, and at the upper end inside the foil holding flange. A step portion for forming a slit of 1 mm or less in parallel with the window foil, between the lower end portion of the inside of the window and the slit; Ri electron beam irradiation device comprising spraying parallel cooling gas supplied to the window foil from the drift space.

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