WO2008062667A1

WO2008062667A1 - Electron beam irradiation apparatus

Info

Publication number: WO2008062667A1
Application number: PCT/JP2007/071604
Authority: WO
Inventors: Tatsuya Matsumura
Original assignee: Hamamatsu Photonics K.K.
Priority date: 2006-11-24
Filing date: 2007-11-07
Publication date: 2008-05-29
Also published as: JP2008128971A; JP4620034B2; TW200832448A

Abstract

In an electron beam irradiation apparatus (1), a second window unit (5) having an outer window (34) is provided opposing a first window unit (4) having an electron beam exit window (24). This prevents dirt from adhering to the electron beam exit window (24) because the outer window (34) blocks flying particles and the like produced when an irradiation object is irradiated with an electron beam (EB). Further, in the electron beam irradiation apparatus (1), the thickness of the outer window (34) in the direction of the exit axis of the electron beam (EB) is made smaller than the thickness of the electron beam exit window (24) in the direction of the exit axis of the electron beam (EB). Accordingly, the output loss occurring when the electron beam (EB) exiting the electron beam exit window (24) passes through the outer window (34) is suppressed to be extremely small, so that a sufficient dose of the electron beam (EB) emitted to the outside of the apparatus can be ensured.

Description

Specification

Electron beam irradiation device

Technical field

[0001] The present invention relates to an electron beam irradiation apparatus.

Background art

An electron beam irradiation device is a device that houses an electron gun that emits an electron beam in a container and emits the electron beam into the atmosphere through an electron beam emission window formed of a thin film. Such an electron beam irradiation apparatus has uses such as drying, sterilization, and surface modification of an irradiation object.

[0003] By the way, when the electron beam irradiation apparatus is actually operated, scattered objects or dirt generated when the irradiation object is irradiated with an electron beam may adhere to the emission window. Therefore, there is also an electron beam irradiation apparatus in which another window (outer window) is provided outside the electron beam emission window and has a double window structure (see, for example, Patent Document 1).

Patent Document 1: JP-A-8-166497

Disclosure of the invention

Problems to be solved by the invention

[0004] In the electron beam irradiation apparatus having the double window structure as described above, it is considered that energy is lost when the electron beam passes through the outer window, resulting in output loss. This is considered to be more remarkable when the energy of the electron beam is small. Therefore, in order to irradiate the irradiation object with a sufficient dose of electron beam, a technology that can suppress the output loss of the electron beam in the outer window as much as possible while preventing dirt from adhering to the electron beam emission window is desired. It is rare.

[0005] The present invention has been made to solve the above-described problems, and can sufficiently secure the dose of an electron beam emitted to the outside of the apparatus while preventing the adhesion of dirt to the electron beam emission window. An object of the present invention is to provide an electron beam irradiation apparatus that can perform this.

Means for solving the problem

In order to solve the above problems, an electron beam irradiation apparatus according to the present invention accommodates an electron gun having an electron emission member that emits an electron beam, an electron emission member, and allows an electron beam to pass therethrough. And a first window unit having an electron beam emission window fixed to the container so as to close the electron beam passage hole and emitting the electron beam having passed through the electron beam passage hole to the outside of the container. And a second window unit that is fixed to the first window unit and has an outer window that emits an electron beam emitted from the electron beam emission window to the outside of the apparatus, and in the direction of the emission axis of the electron beam in the outer window The special feature is that the thickness is smaller than the thickness of the electron beam exit window in the electron beam exit axis direction.

[0007] In this electron beam irradiation apparatus, a second window unit having an outer window is provided for a first window unit having an electron beam exit window. For this reason, the scattered matter generated when the irradiation object is irradiated with the electron beam is blocked by the outer window, and the contamination of the electron beam emission window is prevented. Further, in this electron beam irradiation apparatus, the thickness of the outer window in the electron beam exit axis direction is smaller than the thickness of the electron beam exit window in the exit axis direction. Therefore, the output loss when the electron beam emitted from the electron beam emission window passes through the outer window can be suppressed to be extremely small, and the dose of the electron beam emitted to the outside of the apparatus can be secured sufficiently.

[0008] The second window unit is preferably detachable with respect to the first window unit. This makes it easy to replace the second window unit when dirt adheres to the outer window. In addition, since it is not necessary to remove the first window unit from the container, a step of vacuum leakage in the container is also unnecessary.

[0009] Further, it is preferable to further include an introduction pipe for introducing an inert gas into a space between the first window unit and the second window unit, and a discharge pipe for discharging the inert gas from the space. . With such a configuration, an inert gas can flow between the first window unit and the second window unit. It is possible to fiddle the chilled cocoon.

[0010] The second window unit preferably has a current readout electrode arranged so as not to overlap the outer window when viewed from the electron beam emission axis direction. In this case, among the electron beams emitted from the outer window, the current generated by the electron beam returning to the outer window due to scattering or the like can be measured, and the actual output of the electron beam can be accurately measured in real time. It becomes. In addition, the current reading electrode does not block a part of the outer window. It can be secured.

The invention's effect

[0011] According to the electron beam emitting apparatus of the present invention, it is possible to sufficiently secure the dose of the electron beam emitted to the outside of the apparatus while preventing the adhesion of dirt to the electron beam emitting window.

Brief Description of Drawings

FIG. 1 is a side sectional view showing a configuration of an electron beam irradiation apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a plan view of each window unit as viewed from the exit axis direction of the electron beam EB.

FIG. 4 is an enlarged side sectional view of each window unit.

FIG. 5 is a side sectional view showing a configuration of an electron beam irradiation apparatus according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view taken along line VI—VI in FIG.

FIG. 7 is a plan view of each window unit as viewed from the exit axis direction of the electron beam EB.

FIG. 8 is an enlarged side sectional view of the window unit.

Explanation of symbols

[0013] 1, 40 ... Electron beam irradiation device, 2 ... Electron gun, 3 ... Container, 4, 41 ... First window unit, 5, 42 ... Second window unit, 9 ··· Filament (electron emitting member), 14 ··· Electron beam passage hole, 24, 54… Electron beam exit window, 30, 57 ··· Inlet tube, 31, 58 ··· Discharge tube, 32 ··· Disc member (current readout electrode), 34, 63 ··· Outer window, 61 ··· Plate member (current readout electrode), ΕΒ ··· Electron beam, S2_ space. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the electron beam irradiation apparatus according to the present invention will be described in detail with reference to the drawings.

[First embodiment]

FIG. 1 is a side sectional view showing a configuration of an electron beam irradiation apparatus according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. As shown in FIGS. 1 and 2, the electron beam irradiation apparatus 1 includes an electron gun 2 that emits an electron beam EB, and a container 3 that houses a filament (electron emission member) 9 at the tip of the electron gun 2. The first window unit 4 that emits the electron beam EB from the container 3 and the electron beam EB emitted from the window unit 4 are emitted to the outside of the apparatus. And a second window unit 5. This electron beam irradiation apparatus 1 irradiates an irradiation object (not shown) flowing on the line with an electron beam EB in an atmosphere of an inert gas such as nitrogen, for example, to dry, sterilize, and modify the surface of the irradiation object. It is configured as a device that performs quality etc.

[0016] The electron gun 2 has a rectangular parallelepiped case 6, an insulating block 7 made of an electrically insulating material, a high breakdown voltage connector 8, and a filament 9 that emits an electron beam EB. ing. The case 6 is formed of metal, for example, and is fixed to the proximal end side of the container 3. An opening 6 a that communicates the inside of the case 6 and the accommodation space S 1 in the container 3 is provided on the wall of the case 6 on the container 3 side. Further, an opening 6b for attaching the connector 8 is provided on the side wall of the case 6! /. The inner wall of the case 6 around the opening 6b is provided with an uneven portion so as to ensure the bonding strength with the insulating block 7.

The insulating block 7 is made of an electrically insulating material such as an epoxy resin, and insulates the power supply path from the connector 8 to the filament 9 from the outside. The insulating block 7 has a base portion 7a housed in the case 6, and a frustoconical projecting portion 7b projecting from the base portion 7a to the housing space S1 side in the container 3 through the opening 6a. Yes. The base 7a occupies most of the inside of the case 6 and is in contact with the inner walls of the case 6 on the opening 6a side and the opening 6b side. A conductive film 10 is attached to a portion of the base portion 7a that does not contact the inner wall of the case 6. By electrically connecting the film 10 to the case 6 having the ground potential, the surface potential of the insulating block 7 facing the inner surface of the case 6 can be set to the ground potential, which improves the stability during operation. Figured.

The connector 8 is a connector for supplying a power supply voltage to the filament 9 from the outside of the electron beam irradiation apparatus 1. The connector 8 is inserted into the opening 6 b on the side surface of the case 6, and is buried and fixed in the insulating block 7 with the tip portion positioned near the center of the insulating block 7. The tip portion of the connector 8 is provided with an uneven portion similar to the inner wall of the case 6 so as to ensure the bonding strength with the insulating block 7.

[0019] The base end of the connector 8 is provided with a plug inlet 8a for a power plug that holds the distal end of an external wiring (not shown) that extends the power supply device force. A pair of internal wires 11, 11 is connected to the tip of the connector 8. Internal wiring 11 and 11 are insulated from the tip of connector 8. The lock 7 extends toward the center of the base portion 7a, bends from the center of the base portion 7a toward the protruding portion 7b, and extends to the tip of the protruding portion 7b through the center of the protruding portion 7b.

[0020] The filament 9 is a member that emits electrons to be the electron beam EB. The filament 9 is attached to the tip of the protruding portion 7b of the insulating block 7 and connected to the internal wirings 11 and 11. A grid portion 12 is provided around the filament 9. The grid part 12 is electrically connected to one of the internal wirings 11 and 11, and when a high voltage is applied to the filament 9, a high voltage is also applied to the grid part 12, An electric field for extracting electrons from the filament 9 is formed. The electrons extracted from the filament 9 are emitted as an electron beam EB from a hole formed at the center of the grid portion 12. In addition, when it is desired to control the emission of electrons from the filament 9 more precisely, for example, in the same way as the internal wirings 11 and 11, a wiring for the grid portion 12 is added separately and independent of the potential of the filament 9. It is preferable to control the potential of the grid part 12.

The container 3 is formed in a cylindrical shape extending along the emission axis of the electron beam EB, and is hermetically sealed to the case 6 of the electron gun 2. A cylindrical accommodation portion 13 that accommodates the filament 9 of the electron gun 2, the grid portion 12, and the protruding portion 7 b of the insulating block 7 is formed inside the container 3 on the proximal end side. The diameter of the accommodating portion 13 is larger than that of the opening 6a of the case 6 and extends from the base end of the container 3 to the vicinity of the center. In addition, an electron beam passage hole 14 that communicates with the accommodating portion 13 is formed inside the distal end side of the container 3. The electron beam passage hole 14 has a cylindrical shape with a smaller diameter than the accommodating portion 13 and extends from the vicinity of the center of the container 3 to the tip of the container 3 along the emission axis of the electron beam EB. The tip of the container 3 is provided with a plurality of (for example, six) screw holes (not shown) with a predetermined phase angle!

Around the electron beam passage hole 14, an electromagnetic coil 15 and an electromagnetic coil 16 are arranged along the emission axis of the electron beam EB. The arrangement center of the electromagnetic coil 15 and the electromagnetic coil 16 coincides with the central axis of the electron beam passage hole 14. By the cooperation of the electromagnetic coil 15 and the electromagnetic coil 16, the electron beam EB passing through the electron beam passage hole 14 is focused toward an electron beam exit window 24 described later.

[0023] More specifically, the electromagnetic coil 15 includes a mechanical center shift of each member constituting the passage path of the electron gun 2 and the electron beam EB, a residual magnetism of each component member, and a magnetic field around the installation site. This is a alignment coil for correcting the deviation of the electron beam EB with respect to a desired passage path (center axis of the electron passage hole 14) caused by the influence of the above. In the present embodiment, four electromagnetic coils 15 are arranged with a phase angle of 90 degrees across the electron beam passage hole 14 so that two opposing electromagnetic coils 15 function as a pair. Used. On the other hand, the electromagnetic coil 16 is a bundling coil for collecting the electron beam EB emitted from the electron gun 2 to the electron beam emission window 24. The electromagnetic coil 16 is a magnetic coil composed of a cylindrical coil portion made of enameled wire and soft iron. It consists of a circuit. The electron beam EB emitted from the filament 9 by these electromagnetic coils 15 and 16 accurately passes through the central axis of the electron passage hole 14 and does not collide with the inner wall of the electron passage hole 14. Accurately led to the center of

As shown in FIG. 2, an exhaust pipe 17 is provided on the side of the container 3. The front end of the exhaust pipe 17 is connected to a vacuum pump 18 that exhausts the accommodating portion 13 and the electron beam passage hole 14. The exhaust pipe 17 and the vacuum pump 18 are provided at positions that do not overlap the connector 8 when the electron beam irradiation apparatus 1 is viewed from the direction of the emission axis of the electron beam EB. As a result, interference between the power supply plug and external wiring inserted into the connector 8 and the vacuum pump 18 can be avoided, and the electron beam irradiation apparatus 1 can be downsized.

Next, the configuration of the first window unit 4 and the second window unit 5 will be described with reference to FIG. 3 and FIG. FIG. 3 is a plan view of each window unit as viewed from the exit axis direction of the electron beam EB. FIG. 4 is an enlarged side sectional view of each window unit.

[0026] As shown in the figure, the window unit 4 is a structure on one end side of the electron beam irradiation device 1 for emitting the electron beam EB that has passed through the electron beam passage hole 14 to the outside of the container 3. Unit. The first window unit 4 includes a pedestal 21, a window substrate 22, a cap 23, an electron beam emission window 24, and an outer member 25. The pedestal 21 is made of, for example, stainless steel, and includes a cylindrical barrel portion 21a and a flange portion 21b provided at the base end side edge of the barrel portion 21a.

[0027] A through hole 21c having the same diameter as the electron beam passage hole 14 is formed at the center of the body portion 21a. In addition, a circular recess 21d for setting the window substrate 22 is formed at the tip of the body portion 21a. Further, a male thread portion 2 le for attaching the cap 23 is formed on the outer surface of the trunk portion 21a. On the other hand, an insulating ring 26 is provided on the flange portion 21b. The insulating ring 26 is formed of an electrically insulating material such as polytetrafluoroethylene, and is fixed to the flange portion 21b so as to surround the body portion 21a.

[0028] Further, in the flange portion 21b, six bolt holes 27 having a phase angle of about 60 ° are provided at positions outside the insulating ring 26 (see Fig. 3). The pedestal 21 passes the bolts 28 through the respective borehole holes 27 and screws the bolts 28 into the screw holes of the container 3 so that the through holes 21c and the electron beam passage holes 14 are concentric. It is firmly fixed to the tip of 3. A groove in which an O-ring 38 is installed is formed at the tip of the container 3 so that the hermetic seal between the pedestal 21 and the container 3 is maintained. The pedestal 21 may be formed integrally with the container 3. In this case, it is not necessary to provide the O-ring 38 at the tip of the container 3.

[0029] The window substrate 22 is made of, for example, stainless steel, and includes a cylindrical barrel portion 22a and a flange portion 22b provided at an edge on the proximal end side of the barrel portion 22a. A through hole 22c having a slightly smaller diameter than the through hole 21c of the base 21 is formed at the center of the body portion 22a. Further, a rectangular recess 22d for setting the electron beam exit window 24 is formed at the tip of the body 22a. The window substrate 22 is disposed in the recess 21d of the pedestal 21 with the through hole 22c and the electron beam passage hole 14 being concentric.

[0030] The cap 23 is made of, for example, stainless steel, and includes a circular zenith portion 23a and a cylindrical threaded portion 23b formed on one end side of the zenith portion 23a. In the center of the zenith 23a, an opening 23c having a diameter larger than the outer diameter of the trunk 22a of the window substrate 22 is formed. The inner diameter of the threaded portion 23b is substantially the same as the outer diameter of the trunk portion 21a of the pedestal 21, and the inner surface of the threaded portion 23b is connected to the male threaded portion 21e on the outer surface of the barrel portion 21a. A corresponding female thread portion 23d is formed.

[0031] Then, the cap 23 is formed by screwing the female threaded portion 23d of the threaded portion 23b with the male threaded portion 21e of the pedestal 21, so that the body portion 22a of the window substrate 22 and the electron beam emission window 24 are fitted into the opening 23c. It is fitted in the base 21 in a state of passing through. Thus, the flange portion 22b of the window substrate 22 is pressed against the bottom surface of the recess 21d of the base 21 by the top portion 23a of the cap 23, and the window substrate 22 and the base 21 are firmly fixed. Further, a groove in which an O-ring 39 is installed is formed on the bottom surface of the recess 21d in the base 21. As a result, the window substrate 22 and the base 21 Hermetic sealing is maintained. Note that the O-ring 38 and the O-ring 39 are arranged so as to overlap when viewed from the emission direction of the electron beam EB, and surround the vicinity of the passage path of the electron beam EB. Therefore, the pressing force applied to the O-rings 35 and 36 is almost equal, and a highly reliable sealing is possible.

The electron beam exit window 24 is a foil-like member that emits the electron beam EB that has passed through the electron beam passage hole 14 of the container 3 to the outside of the container 3. The electron beam exit window 24 is formed in a rectangular shape by, for example, beryllium, and the thickness of the electron beam exit window 24 in the direction of the exit axis of the electron beam EB is about 10 m. The electron beam emission window 24 is disposed on the bottom surface of the recess 22d of the window substrate 22 so as to close the tip of the through hole 22c of the window substrate 22, and is airtightly fixed to the window substrate 22 by brazing, for example. The electron beam exit window 24 may be made of a material having a high electron beam EB transmittance, such as titanium or aluminum in addition to the above-described beryllium.

The outer member 25 is made of stainless steel, for example, and has a hollow cylindrical shape having the same diameter as the insulating ring 26 provided on the flange portion 21b of the base 21. The outer member 25 is disposed so as to cover the trunk portion 21a of the pedestal 21, the window substrate 22, the cap 23, and the electron beam emission window 24, and is fixed to the flange portion 21b of the pedestal 21 via the insulating ring 26. A plurality of (for example, four) screw holes 25 a having a predetermined phase angle are provided at the front end of the outer member 25. In addition, an introduction pipe 30 is formed on the side surface of the outer member 25, and a discharge pipe 31 is formed on the opposite side of the introduction pipe 30. The introduction pipe 30 and the discharge pipe 31 are connected to a nitrogen gas circulation device (not shown). Note that when the outer member 25 is fixed to the flange portion 21b of the base 21, it may be directly fixed without using the insulating ring 26. In this case, the insulating ring 26 is preferably arranged between the outer member 25 and the second window unit 5.

On the other hand, the second window unit 5 includes a disk member 32, an outer window mounting ring 33, and an outer window 34. The disc member 32 is formed with the same diameter as the outer diameter of the outer member 25 by, for example, stainless steel. An opening 32a having a diameter slightly smaller than the outer diameter of the body 22a of the window substrate 22 is formed in the central portion of the disc member 32. For example, six screw holes 32b are formed around the opening 32a! In addition, four screw holes 32 c corresponding to the screw holes 25 a of the outer member 25 are formed at the edge of the disc member 32. The disk member 32 is screwed into the screw hole 25a and the screw hole 32c so that the screw hole 32b faces the electron beam emission window 24 and the opening 32a is It is detachably fixed to the distal end of the outer member 25 so as to be concentric with the passage hole 14.

Furthermore, a lead wire (not shown) is attached to the disc member 32. This lead wire is connected to an ammeter 29 installed outside the electron beam irradiation apparatus 1 (see Fig. 1). With such a configuration of the disc member 32, the disc member 32 functions as a current reading electrode into which a part of the electron beam EB flows. That is, of the electron beam EB emitted from the outer window 34, the electron beam EB returned to the outer window 34 side due to the influence of scattering or the like flows into the disc member 32. The current generated by the electron beam EB flowing into the disk member 32 is sent to the ammeter 29 through the lead wire. The disc member 32 may be formed integrally with the outer member 25.

The outer window mounting ring 33 is a flat member having a smaller diameter than the disk member 32. Outside window mounting ring

An opening 33 a having a diameter larger than that of the electron beam exit window 24 is formed in the central portion of 33. Six screw holes 33b corresponding to the screw holes 32b of the disk member 32 are formed around the opening 33a. The outer window mounting ring 33 is screwed into each of the screw hole 32b and the screw hole 33b so that the opening 32a is concentric with the electron beam passage hole 14 on the back side of the disk member 32. It is fixed.

The outer window 34 is a foil-like member that emits the electron beam EB emitted from the electron beam emission window 24 to the outside of the apparatus 1. The outer window 34 is formed of, for example, aluminum in a rectangular shape, and the thickness of the electron beam EB in the outer window 34 in the emission axis direction is about several meters. The outer window 34 is brazed and fixed to one surface side of the outer window mounting ring 33 so as to close the opening 33 a of the outer window mounting ring 33, and is disposed in the opening 32 a of the disk member 32.

[0039] Here, since it is not necessary to hermetically seal between the outer window 34 and the outer window mounting ring 33, the outer window 34 is fixed to the outer window mounting ring 33 and the disc instead of being fixed by brazing. You may fix by pinching with the member 32. FIG. In this case, if the opening 33a of the outer window mounting ring 33 and the opening 32a of the disk member 32 have the same dimensions, for example, when fixing the outer window 34, etc. In addition, it is possible to prevent the outer window 34 from being damaged by hitting the edges of the opening 32a and the opening 33a.

[0040] The thickness of the outer window 34 in the direction of the emission axis of the electron beam EB is equal to the electron beam emission window described above.

Electron beam EB is a force that is smaller than the thickness of the electron beam EB in the exit axis direction.Because it is not necessary to maintain tight airtightness between the first window unit 4 and the second window unit 5, the electron beam EB From the viewpoint of further reducing the output loss, the outer window 34 can be made as thin as about 1 μm. Furthermore, the material constituting the outer window 34 may include a material having an atomic number larger than that of the material constituting the electron beam emission window 24. Examples of the material constituting the outer window 34 include carbon (organic film), aluminum, silicon, titanium, nickel, copper, silver, gold, and various alloys. Since these materials are excellent in heat resistance, they are excellent in durability as an outer window.

In the electron beam irradiation apparatus 1 having the above-described configuration, the inside of the container 3 is evacuated by the vacuum pump 18, and a voltage of about several tens kV to several hundreds kV from an external power source through the internal wirings 11 and 11. Is supplied to the filament 9, electrons are emitted from the filament 9. The electrons emitted from the filament 9 are accelerated by the electric field formed by the grid portion 12, and become an electron beam EB. When the electron beam EB passes through the electron beam passage hole 14, the central axis is corrected by the electromagnetic coil 15, and then converged by the electromagnetic coil 16, and passes through the electron beam emission window 24 and the outer window 34 to the outside. Exit. The emitted electron beam EB is irradiated to an irradiation object such as a printed material flowing on the line in an inert gas atmosphere such as nitrogen gas.

[0042] When the electron beam EB is emitted from the electron beam emission window 24 and the outer window 34, a part of the electron beam EB toward the irradiation object returns to the outer window 34 side due to the influence of scattering or the like, and the second It flows into the disk member 32 of the window unit 5. The current generated when part of the electron beam EB flows is sent from the disk member 32 to the ammeter 29, and the current value is monitored. A certain amount of nitrogen gas is introduced into the space S2 between the first window unit 4 and the second window unit 5 from the introduction pipe 30. The nitrogen gas introduced into the space S2 is discharged from the discharge pipe 31 to the nitrogen gas circulation device.

[0043] As described above, in the electron beam irradiation apparatus 1, the second window unit 5 having the outer window 34 is provided for the first window unit 4 having the electron beam emission window 24. . Therefore, electric Scattered matter or the like generated when the beam EB is irradiated onto the irradiation object is blocked by the outer window 34, and contamination of the electron beam emission window 24 is prevented. In the electron beam irradiation apparatus 1, the thickness force of the outer window 34 in the direction of the emission axis of the electron beam EB is smaller than the thickness of the electron beam EB in the direction of the emission axis of the electron beam EB. Therefore, the output loss when the electron beam EB emitted from the electron beam emission window 24 passes through the outer window 34 can be suppressed extremely small, and the dose of the electron beam EB emitted outside the apparatus can be sufficiently secured. .

In the electron beam irradiation apparatus 1, the disc member 32 of the second window unit 5 also functions as a current readout electrode. Therefore, the surface state of the outer window 34 that changes over time due to unevenness in the thickness of the electron beam exit window 24 and adhesion of scattered objects and dirt generated when the electron beam EB is irradiated onto the irradiation object. In addition, the output (actual output) of the electron beam EB actually emitted from the outer window 34 can be measured in real time with high accuracy. Further, since the disc member 32 is disposed so as not to overlap the electron beam exit window 24 and the outer window 34 when viewed from the exit axis direction of the electron beam EB, the electron beam EB from the electron beam exit window 24 is arranged. A sufficient amount of light can be secured.

[0045] If the actual output of the electron beam EB is confirmed to have decreased, it is considered that the dirt is attached to the outer window 34, so the outer window 34 must be replaced. . In this case, in the electron beam irradiation apparatus 1, the second window unit 5 can be easily detached from the first window unit 4 by removing the screw 35. Therefore, the outer window 34 can be easily replaced. Further, since it is not necessary to remove the first window unit 4 from the container 3, a step of vacuum leaking the container 3 is also unnecessary. For this reason, it is possible to significantly shorten the downtime of the apparatus when performing window replacement.

[0046] Further, in the electron beam irradiation apparatus 1, the introduction pipe 30 for introducing nitrogen gas into the space S2 between the first window unit 4 and the second window unit 5 and the nitrogen gas is discharged from the space S2. And a discharge pipe 31 to be provided. With such a configuration, generation of ozone in the space S2 when the electron beam EB is emitted from the electron beam emission window 24 is suppressed. Further, the cooling effect of the electron beam emission window 24 and the outer window 34 can be obtained by the flow of nitrogen gas in the space S.

[Second Embodiment]

[0047] Next, an electron beam irradiation apparatus according to the second embodiment of the present invention will be described in detail. FIG. 5 is a side sectional view showing the configuration of the electron beam irradiation apparatus according to the second embodiment of the present invention. 6 is a cross-sectional view taken along line VI-VI in FIG. As shown in FIG. 5 and FIG. 6, the electron beam irradiation apparatus 40 according to the second embodiment uses the deflection coil 52 to move the electron beam EB that has passed through the electron beam passage hole 14 of the container 3 in a predetermined direction at high speed. By deflecting the electron beam EB from the first window unit 41 and the second window unit 42 in a linear manner, the electron beam EB is emitted from the first window unit 4 and the second window unit 5 at one point. Different from the first embodiment.

[0049] The configurations of the first window unit 41 and the second window unit 42 will be described. FIG. 7 is a plan view of each window unit as viewed from the exit axis direction of the electron beam EB. FIG. 8 is an enlarged side sectional view of each window unit.

As shown in FIGS. 7 and 8, the window unit 41 includes a casing 51, a window substrate 53, an electron beam emission window 54, and an outer member 55. The casing 51 has a shape in which the width in the deflection direction of the electron beam EB (the X direction in FIG. 5) increases as the force is directed from the proximal end side to the distal end side. An opening 51a having the same diameter as the electron beam passage hole 14 is formed on the base end side of the casing 51, and the distal end side of the casing 51 is opened in a rectangular shape. Further, a circular flange portion 51b is formed on the base end side edge of the casing 51. The casing 51 is positioned so that the opening 51a and the electron beam passage hole 14 are concentric, and is hermetically fixed to the tip of the container 3.

In addition, a deflection coil 52 is provided in the vicinity of the flange portion 51b on the base end side of the casing 51. The deflection coil 52 is a coil that deflects the electron beam EB that has passed through the electron beam passage hole 14 in the housing 51. L-shaped support members 52a are attached to both ends of the deflection coil 52. The deflection coil 52 is sandwiched between the support members 52a and 52a so that the side wall on the proximal end side of the casing 51 is sandwiched therebetween. The body 51 is disposed so as to be close to one of the side walls orthogonal to the deflection direction. The deflection coil 52 is linear in the direction of travel of the electron beam EB that has passed through the electron beam passage hole 14 based on the current value supplied from an external power source (not shown). To deflect.

The window substrate 53 is formed in a rectangular shape using, for example, stainless steel, and is fixed to the tip of the housing 51. In the center of the window substrate 53, a plurality (five in this embodiment) of rectangular through holes 53a are formed. Each through-hole 53a has a predetermined interval along the deflection direction of the electron beam EB. Are arranged in a row. Further, a partition groove 53b is formed between the through holes 53a and 53a in a direction orthogonal to the deflection direction of the electron beam EB. A rectangular annular insulating ring 56 made of, for example, polytetrafluoroethylene is fixed to the edge of the window substrate 53. Similarly to the first embodiment, the electron beam exit window 54 is formed in a rectangular shape by, for example, beryllium, and the thickness of the electron beam exit window 54 in the direction of the exit axis of the electron beam EB is about lO ^ m. Yes. The electron beam emission window 54 is provided for each through hole 53a, and is brazed to the window substrate 53 so as to block the tip of each through hole 53a. Note that a groove in which an O-ring 60 is installed is formed at the tip of the casing 51. As a result, hermetic sealing between the window substrate 53 and the casing 51 is maintained.

The outer member 55 has a hollow rectangular parallelepiped shape having the same dimensions as the window substrate 53, and is fixed to the window substrate 53 via an insulating ring 56. Screw holes 55a are formed at both ends in the X direction on the distal end side of the outer shell member 55, respectively. An introduction pipe 57 is formed on the side surface in the X direction of the outer member 55, and a discharge pipe 58 is formed on the opposite side of the introduction pipe 57. The introduction pipe 57 and the discharge pipe 58 are connected to a nitrogen gas circulation device (not shown). When the outer member 55 is fixed to the window substrate 53, it may be directly fixed without using the insulating ring 56. In this case, the insulating ring 56 is preferably disposed between the outer member 55 and the second window unit 42.

[0054] The second window unit 42 includes a plate member 61, an outer window mounting member 62, and an outer window 63. The plate member 61 is formed, for example, of stainless steel with the same dimensions as the outer member 55. A rectangular opening 61 a that exposes each electron beam emission window 54 is formed in the central portion of the plate member 61, and both ends of the plate member 61 in the X direction correspond to the screw holes 55 a of the outer member 55. Screw holes 61b are formed respectively. Further, on one surface side of the plate member 61, a screw hole 61c is formed at a position inside the screw hole 61b so as to sandwich the opening 61a. Then, the plate member 61 is screwed into the screw hole 55a and the screw hole 6 lb, respectively, so that the screw hole 61c faces the electron beam emission window 54 at the tip of the outer member 55. Removably fixed! /

Furthermore, a lead wire (not shown) is attached to the plate member 61. This lead wire is connected to an ammeter 29 installed outside the electron beam irradiation device 40 (see FIG. 5). This With the configuration of the plate member 61 as described above, the plate member 61 functions as a current reading electrode into which a part of the electron beam EB flows. That is, among the electron beams EB emitted from the outer window 63, the electron beams EB returning to the outer window 63 side due to the influence of scattering and the like flow into the plate member 61. The current generated by the electron beam EB flowing into the plate member 61 is sent to the ammeter 29 through the lead wire. The plate member 61 may be formed integrally with the outer member 55.

The outer window mounting member 62 has a flat rectangular shape with a width dimension smaller than that of the plate member 61.

A rectangular opening 62 a that exposes the electron beam emission window 54 is formed at the center of the outer window mounting member 62, as with the plate member 61. In addition, screw holes 62b corresponding to the screw holes 61c of the plate member 61 are formed at the edge portions in the X direction of the outer window mounting member 62, respectively. The outer window attaching member 62 is fixed to the back side of the plate member 61 by screwing screws 65 into the screw holes 61c and 62b.

[0057] The outer window 63 is formed in a rectangular shape, for example, from aluminum, and the thickness of the outer window 63 in the direction of the emission axis of the electron beam EB is about several meters. The outer window 63 is brazed and fixed to one surface side of the outer window mounting member 62 so as to close the opening 62 a of the outer window mounting member 62, and is disposed in the opening 61 a of the plate member 61.

[0058] As in the first embodiment, since there is no need to hermetically seal between the outer window 63 and the outer window mounting member 62, instead of fixing by brazing, the outer window 63 is connected to the outer window mounting member 62. You may fix by pinching with the board member 61. FIG. In this case, if the opening 62a of the outer window attaching member 62 and the opening 61a of the plate member 61 have the same dimensions, for example, when the outer window 62 is fixed, the opening 61a and the opening It is possible to prevent the outer window 63 from being damaged by hitting the edge of 62a.

Further, the thickness of the outer window 63 in the direction of the emission axis of the electron beam EB is smaller than the thickness of each electron beam emission window 54 described above in the direction of the emission axis of the electron beam EB. Since it is not necessary to maintain tight airtightness between the unit 41 and the second window unit 42, the outer window 63 is thinned to about 1 μm from the viewpoint of further reducing the output loss of the electron beam EB. It is also possible to do this.

In such an electron beam irradiation apparatus 40 as well, as in the first embodiment, a second window unit having an outer window 63 with respect to a first window unit 41 having an electron beam emission window 54. 42 provided It has been. For this reason, the scattered matter generated when the irradiation object is irradiated with the electron beam EB is blocked by the outer window 63, and contamination of the electron beam emission window 54 is prevented. Further, in the electron beam irradiation apparatus 40, the thickness force of the outer window 63 in the direction of the emission axis of the electron beam EB is smaller than the thickness of the electron beam emission window 54 in the direction of the emission axis of the electron beam EB. Therefore, the output aperture when the electron beam EB emitted from the electron beam emission window 54 passes through the outer window 63 can be kept extremely small, and a sufficient dose of the electron beam EB emitted outside the apparatus can be secured. That's the power S.

In the electron beam irradiation apparatus 40, the plate member 61 of the second window unit 42 also functions as a current readout electrode. Therefore, the surface condition of the outer window 63 that changes over time due to unevenness of the thickness of the electron beam exit window 54 and adhesion of scattered objects and dirt generated when the electron beam EB is irradiated on the irradiation object. In addition, the actual output of the electron beam EB actually emitted from the outer window 63 can be accurately measured in real time. Further, since the plate member 61 is disposed so as not to overlap the electron beam emission window 54 and the outer window 63 when viewed from the emission axis direction of the electron beam EB, the emission of the electron beam EB from the outer window 63 is performed. Enough amount can be secured

[0062] When the actual output of the electron beam EB is confirmed to have decreased, it is considered that the dirt is attached to the outer window 63, and therefore the outer window 63 must be replaced. . In this case, in the electron beam irradiation apparatus 40, the second window unit 42 can be easily detached from the first window unit 41 by removing the screw 64. Therefore, the outer window 63 can be easily replaced. Further, since it is not necessary to remove the first window unit 41 from the container 3, a step of vacuum leaking the inside of the container 3 is also unnecessary. For this reason, it is possible to significantly shorten the equipment stop time when performing window replacement.

[0063] Further, in the electron beam irradiation apparatus 40, the introduction pipe 57 for introducing nitrogen gas into the space S2 between the first window unit 41 and the second window unit 42, and the nitrogen gas is discharged from the space S2. Equipped with a discharge pipe 58. With such a configuration, generation of ozone in the space S2 when the electron beam EB is emitted from the electron beam emission window 54 is suppressed. Further, the cooling effect of the electron beam emission window 54 and the outer window 63 is obtained by the flow of nitrogen gas in the space S2.

Industrial applicability According to the electron beam emitting apparatus of the present invention, it is possible to sufficiently secure the dose of the electron beam emitted to the outside of the apparatus while preventing the adhesion of dirt to the electron beam emitting window.

Claims

The scope of the claims

[1] an electron gun having an electron emitting member that emits an electron beam;

A container having an electron beam passage hole for containing the electron emission member and allowing the electron beam to pass through;

A first window unit having an electron beam emission window fixed to the container so as to close the electron beam passage hole and emitting the electron beam that has passed through the electron beam passage hole to the outside of the container;

A second window unit fixed to the first window unit and having an outer window for emitting the electron beam emitted from the electron beam emission window to the outside of the apparatus,

The electron beam irradiation apparatus according to claim 1, wherein a thickness of the electron beam in the exit axis direction of the outer window is smaller than a thickness of the electron beam in the exit axis direction of the electron beam exit window.

2. The electron beam irradiation apparatus according to claim 1, wherein the second window unit is detachable with respect to the first window unit.

[3] An introduction pipe for introducing an inert gas into a space between the first window unit and the second window unit;

The electron beam irradiation apparatus according to claim 1, further comprising a discharge pipe for discharging the inert gas from the space.

[4] The second window unit has a current readout electrode arranged so as not to overlap the outer window when viewed from the direction of the emission axis of the electron beam. 1. The electron beam irradiation apparatus according to 1.