JPH0794135A - Electron beam irradiation device - Google Patents

Abstract

PURPOSE:To prevent a window foil from being broken due to the cooling air and simplify constitution for blowing the cooling air, even when an irradiation window is formed out of a double window foil. CONSTITUTION:An irradiation window 2 is formed out of a double window foil, with the center of a window foil 3 supported on a reinforcement bar 9 and a secondary window foil 11 laid thereunder in such state as supported on the bar 9 at the center. Also, a cooling air duct 15 is provided between the centers of both foils 3 and 11 to blow the cooling air in both directions along the surface of the foils 3 and 11. In this case, the cooling air flows from the centers of the foils 3 and 11 in both directions. Thus, each of the foils 3 and 11 is cooled and the cooling air flowing along the surface thereof comes outside through both sides of the irradiation window 2. As a result, the cooling air does not strongly collide with the foils 3 and 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam irradiation device.

[0002]

As is well known, this type of electron beam irradiation apparatus is
The scanning tube scans the electron beam accelerated by the accelerating tube to irradiate the object to be irradiated.The scanning tube is provided with an irradiation window as an electron beam extraction portion. It is blocked by a window foil. The window foil is cooled by cooling air by blowing compressed air.

FIG. 3 shows the conventional structure, 1 is a scanning tube,
2 is an irradiation window, 3 is a window foil, which is sandwiched by the lower flange 4 and the window pressing flange 5 of the scanning tube 1 and sealed by a metal seal 6. The compressed air duct 7 is provided for the heat generation of the window foil 3 caused by the passage of the electron beam.
The window 8 is cooled by blowing the cooling air from the nozzle 8 onto the window foil 3.

By the way, according to the irradiation window having such a structure, when an electron current of about 100 mA is generated, the temperature of the window foil 3 rises to three hundred and several ten degrees, and it is difficult to further increase the current density. is there. Therefore, in order to increase the current density of the window foil 3, a reinforcing bar 9 is provided at the center of the lower surface of the scanning tube 1, and the central upper surface of the window foil 3 is supported by the reinforcing bar 9.
A continuous window structure is adopted, and cooling air is blown from the compressed air duct 7 and the nozzle 8 from both sides of the window foil 3.

However, when the cooling airflows are blown from both sides of the window foil 3 in this way, the cooling airflows 10 interfere with each other in the center and flow downward, so that the irradiation target under the irradiation window 2 is irradiated. It comes to spray things. When the object to be irradiated is in the form of a sheet due to the downward cooling air, the object to be irradiated may flutter, or the object having weak strength may be broken. Further mesh,
An object to be irradiated that is conveyed by slats, conveyors, etc. may be rolled up.

In order to solve this, another window foil (hereinafter referred to as a secondary window foil) is provided below the window foil 3, and the cooling air blown on the window foil 3 is supplied to the secondary window. It is conceivable to shield it with a foil so that it does not directly hit the irradiated object.

However, in the case of the double window foil structure, the cooling air blown to the window foil 3 interferes at the center and travels downward as in the case of FIG. 3, and hits the secondary window foil strongly. As a result, the secondary window foil may be torn.
Further, since the electron beam also passes through this secondary window foil to generate heat, it is necessary to blow cooling air to cool it.
Therefore, it is necessary to separately prepare the cooling air duct and the nozzle, and the configuration becomes complicated.

[0008]

SUMMARY OF THE INVENTION In an irradiation window having a double window foil structure, the present invention prevents the cooling air blown to the window foil from striking the secondary window foil strongly, and also for each window foil. It is intended to simplify the structure for spraying cooling air.

[0009]

SUMMARY OF THE INVENTION The present invention is a dual window foil having a window foil whose center is supported by a reinforcing bar and a secondary window foil whose center is supported by the bar below the window foil. In the irradiation window configured as described above, a cooling air duct is provided between the centers of both window foils, and cooling air is blown toward both sides of this cooling air duct along the surfaces of both window foils. To do.

[0010]

The cooling air flows from the center of the window foil and the secondary window foil toward both sides thereof through the cooling air duct along the lower surface of the window foil and the upper surface of the secondary window foil to cool each window foil. . After that, the cooling air escapes from both sides of the irradiation window. Therefore, the cooling air does not hit the secondary window foil strongly, and the configuration for blowing the cooling air to each window foil is also simplified.

[0011]

Embodiment An embodiment of the present invention will be described with reference to FIG. It should be noted that the parts denoted by the same reference numerals as those in FIG. 3 indicate the same or corresponding parts. A secondary window foil 11 arranged below the window foil 3 is a metal foil similar to the window foil 3, which is the flange 1
Both ends are supported by 2 and 13, and the center is supported by a crosspiece 14. The window foils 3 and 11 form a double window foil structure.

According to the invention, the window foil 3 and the secondary window foil 11
A cooling air duct 15 is provided in the center between and. As shown in FIG. 2, for example, the cooling air duct 15 is composed of a pair of side walls 16 and lids 13 and 14 that cover the upper and lower opening surfaces of the side walls 16, and between the side wall 16 and the lids 13 and 14. The gap 17 is used as a nozzle. If one end surface of the side wall 16 is closed and compressed air is supplied from the other end surface, the compressed air can be blown out from the gaps 17 on both sides. This compressed air becomes the cooling air 10 and is blown onto the window foil 3 and the secondary window foil 11.

In this way, the cooling air is blown from the center of the window foil 3 and the secondary window foil 11 toward both sides thereof, and the cooling air is blown along the lower surface of the window foil 3 and the upper surface of the secondary window foil 11. By flowing, the window foil 3 and the secondary window foil 11 are cooled. The cooling air 10 that has passed through the surfaces of the window foils 3 and 11 comes out through the discharge passage 18 between the flanges 5 and 12 to both sides of the irradiation window 2 as it is. Therefore, the cooling air 10 is discharged without hitting each window foil strongly.

[0014]

As described above, according to the present invention, even when the irradiation window has a double window foil structure, the cooling air does not hit the window foil strongly and therefore the window foil may be broken. There is no cooling duct, and a cooling duct is provided in the center between both window foils so that cooling air is blown out from both sides, so cooling ducts and nozzles for each window foil are not required. The structure for spraying is effective in being extremely simple.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a partial perspective view of a cooling duct.

FIG. 3 is a sectional view of a conventional example.

[Explanation of symbols]

 1 Scanning Tube 2 Irradiation Window 3 Window Foil 9 Reinforcing Bar 11 Secondary Window Foil 14 Bar 15 Cooling Air Duct

Claims (1)

[Claims] 1. An irradiation window having a double window foil structure having a window foil whose center is supported by a reinforcing bar and a secondary window foil whose center is supported by the bar below the window foil. In the electron beam irradiation device, a cooling air duct is provided in the center between the window foil and the secondary window foil, and cooling air is blown from the cooling air duct toward both sides of the irradiation window along the surfaces of both window foils. An electron beam irradiation device that is sprayed.