JPH0511099U - Electron beam irradiation device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] When the irradiation window flange is locally overheated by scattered electrons and secondary electrons, the resilience of the window foil sealant may be lost. Therefore, the airtightness of the scanning tube portion is impaired. The present invention aims to prevent such leaks. [Structure] A shielding material 12 for shielding scattered electrons and secondary electrons is provided between the beam catcher 5 and the flange 8. The shielding material 12 prevents the scattered electrons and secondary electrons from hitting the flange 8 and prevents the flange 8 from being locally overheated.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electron beam irradiation device.

[0002]

[Prior Art]

 As is well known, the electron beam irradiation apparatus scans the electron beam accelerated by the accelerating tube section 1 by the scanning section 2 as shown in FIG. To do. In this case, since the scanning width of the electron beam needs to be wider than the width of the irradiation target 4, the electron beam outside the width of the irradiation target 4 hits the beam catcher 5 therebelow. The electron beam hits the beam catcher 5 even when the irradiation target 4 does not exist.

The energy of the electron beam hitting the beam catcher 5 in this way is absorbed by the beam catcher 5 to generate heat. Normally, the beam catcher 5 is cooled to prevent its temperature rise. However, part of the electron beam is scattered. Also, secondary electrons may be generated during the absorption process.

Some of the scattered electrons and secondary electrons described above go to the irradiation window 6 of the scanning tube section 3. As shown in FIG. 1, the irradiation window of the scanning tube portion 3 is composed of a window foil 7 that shields the inside of the scanning tube portion 3 that is evacuated from the atmosphere, and a flange 8 that supports the window foil 7. Has been done.

To explain this in detail, the peripheral edge of the window foil 7 is sandwiched between the flange 8 and the lower flange portion 10 of the scanning tube portion 3 via a metal sealing material 9, and the flange 8 and the flange By tightening the portion 10 with the bolt 11, the peripheral edge of the window foil 7 is supported by the flange portion 10.

By the way, in such a structure, scattered electrons or secondary electrons that have gone to the irradiation window 6 as described above may go to the flange 8 and be absorbed there. Then, the flange 8 is locally overheated and expanded. The sealing material 9 is compressed by this expansion. However, when the electron beam irradiation ends, the flange 8 is restored to the initial state by heat radiation.

However, if the sealing material 9 is extremely compressed, it may not be able to restore its original state due to loss of the restoring elasticity. Therefore, the pressing force on the sealing material 9 is reduced, and a gap is generated between the flange 8 and the flange portion 10. When such a gap is generated, it becomes impossible to maintain the airtightness inside the scanning pipe section 3.

[0008]

[Problems to be solved by the device]

 An object of the present invention is to prevent airtight leakage of the scanning tube portion by avoiding expansion of the flange due to scattered electrons and secondary electrons.

[0009]

[Means for Solving the Problems]

 The present invention relates to an electron beam irradiating device having an irradiation window constituted by a window foil for keeping the inside of the scanning tube section airtight and a flange for supporting the window foil on the scanning tube section via a sealing material. , A shielding material has been installed between the beam catcher that absorbs the electron beam emitted through the irradiation window and the flange that supports the window foil to shield scattered electrons and secondary electrons. Is characterized by.

[0010]

[Action]

 Even if scattered electrons and secondary electrons go from the beam catcher side to the flange side, they are prevented from hitting the flange by the shielding member. This will prevent these electrons from locally heating the flange.

[0011]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. According to the present invention, a metallic shielding material 12 is installed between the beam catcher 5 and the flange 8. When such a shielding material 12 is installed, scattered electrons and secondary electrons 13 are shielded by the shielding material 12 and prevented from hitting the flange 8 as shown in FIG.

Therefore, the flange 8 is prevented from being locally overheated and is not expanded or contracted. Therefore, the loss of the restoring elasticity due to the overpressure of the sealing material 9 prevents the airtight leak of the scanning tube 3. Like

[0013]

[Effect of the device]

 As described above, according to the present invention, it is possible to prevent the airtight leak of the scanning tube portion with a simple configuration in which the shielding material is simply installed between the beam catcher and the flange.

[Brief description of drawings]

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

FIG. 2 is a front view showing an embodiment of the present invention.

[Explanation of symbols]

 3 Scan tube part 4 Irradiation object 5 Beam catcher 6 Irradiation window 7 Window foil 8 Flange 9 Sealing material 12 Shielding material

Claims (1)

Claims for utility model registration: 1. A scanning tube section, an irradiation window provided in the scanning tube section, and a beam catcher for absorbing an electron beam irradiated through the irradiation window, In the electron beam irradiation apparatus, wherein the irradiation window is constituted by a window foil for maintaining the inside of the scanning tube section airtight and a flange for supporting the window foil on the scanning tube section via a sealing material, An electron beam irradiation device comprising a shielding material for shielding scattered electrons and secondary electrons directed to the flange between the beam catcher and the flange.