JP2008128978A - Electron beam irradiation equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electron beam irradiation equipment which makes it possible to accurately measure the actual output of an electron beam, in real time. <P>SOLUTION: As to the electron beam irradiation equipment 1, current readout electrodes 5 are placed in a window unit 4 so that they cannot overlap an electron beam emission window 24, as seen from the emission axis direction of an electron beam EB. This enables the electron beam irradiation equipment 1 to measure the current generated by the electron beam EB that has been returned to the side of the electron beam irradiation window 24, by scattering and the like among the electron beams emitted from the electron beam irradiation window 24. After taking into account the conditions of the surface of the electron beam irradiation window 24, which change with the lapse of operation time due to the uneven thickness of the electron beam irradiation window 24 and the deposition of debris and dirt generated in the irradiation of an object with the electron beam EB, the output (actual output) of the electron beam EB emitted actually from the electron beam irradiation window 24 can be measured accurately, in real time, by the electron beam equipment 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electron beam irradiation apparatus.

  The electron beam irradiation apparatus is an apparatus that accommodates an electron gun that emits an electron beam in a container and emits the electron beam into the atmosphere through an 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.

When actually operating the electron beam irradiation apparatus, it is preferable to measure the output of the electron beam from the viewpoint of confirmation of operation performance and maintenance. For example, in the electron beam irradiation processing apparatus described in Patent Document 1, the tube current of the electron beam tube and the current flowing from the electron beam exit window and its flange to the ground are measured with an ammeter, and the difference between the currents is constant. The output of the electron beam is controlled so that
JP 2003-222700 A

  By the way, the surface state of the electron beam exit window may change with the lapse of operation time due to adhesion of scattered matter or dirt generated when the irradiation object is irradiated with the electron beam. Therefore, in the configuration in which the current generated when the electron beam emitted from the electron gun enters the electron beam exit window as in the conventional electron beam irradiation processing apparatus described above, the electrons actually extracted into the irradiation space are measured. The accuracy may be insufficient to measure the output of the line, that is, the output (actual output) of the electron beam transmitted through the electron beam exit window and emitted toward the irradiation object in real time.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electron beam irradiation apparatus that can accurately measure the actual output of an electron beam in real time.

  In order to solve the above problems, an electron beam irradiation apparatus according to the present invention has an electron gun having an electron emission member that emits an electron beam, and an electron beam passage hole that accommodates the electron emission member and allows the electron beam to pass therethrough. A window unit having an electron beam exit window that is fixed to the container so as to close the electron beam passage hole, and emits the electron beam that has passed through the electron beam passage hole to the outside of the container; And a current readout electrode arranged so as not to overlap with the electron beam exit window as viewed from the exit axis direction.

  In this electron beam irradiation apparatus, the current reading electrode is arranged in the window unit so as not to overlap the electron beam emission window when viewed from the electron beam emission axis direction. With this configuration, the electron beam irradiation apparatus can measure the current generated by the electron beam returning to the electron beam exit window side by scattering or the like among the electron beams emitted from the electron beam exit window. It is possible to accurately measure the actual output of the electron beam in consideration of the state of the exit window in real time. In addition, the current reading electrode does not block a part of the electron beam exit window, and a sufficient amount of electron beam emitted from the electron beam exit window can be secured.

  The current reading electrode is preferably coupled to the window unit through a member having electrical insulation. Thus, by insulating the window unit and the current reading electrode, it is possible to separate the current generated by the electron beam flowing into the window unit and the container from the current generated by the electron beam flowing into the current reading electrode. Become. Thereby, the real output of an electron beam can be measured more accurately in real time.

  Further, it is preferable that the current reading electrode is provided with a reading end portion so as to surround the electron beam emission window as seen from the electron beam emission axis direction. In this way, since the electron beam that has returned to the electron beam exit window side due to scattering or the like can be detected more reliably at the reading end, the actual output of the electron beam can be measured more accurately in real time.

  The electron beam exit window preferably protrudes in the electron beam exit direction from the reading end. In this case, it becomes possible to irradiate an electron beam close to the irradiation object.

  Moreover, it is preferable that the reading end portion protrudes in the electron beam emission direction from the electron beam emission window. In this case, the reading end portion can be provided with a function of protecting the electron beam exit window.

  Moreover, it is preferable that the tip of a suction tube for sucking a part of the atmospheric gas outside the electron beam exit window is fixed to the current readout electrode. Usually, irradiation of an electron beam to an irradiation target is performed in an atmosphere of an inert gas such as nitrogen. By fixing the suction tube to the current reading electrode, it is possible to reliably detect the component of the atmospheric gas around the irradiation object.

  With the electron beam irradiation apparatus according to the present invention, it is possible to accurately measure the actual output of the electron beam in real time.

  Hereinafter, preferred embodiments of an 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 the configuration of the electron beam irradiation apparatus according to the first embodiment of the present invention. 2 is a cross-sectional view taken along line II-II in FIG. As shown in FIGS. 1 and 2, an electron beam irradiation apparatus 1 includes an electron gun 2 that emits an electron beam EB, a container 3 that houses a filament (electron emitting member) 9 at the tip of the electron gun 2, and a container 3 includes a window unit 4 for emitting an electron beam EB to the outside from 3 and a current readout electrode 5 for monitoring the output of the electron beam EB emitted from the window unit 4. The electron beam irradiation apparatus 1 irradiates an irradiation object (not shown) flowing on a 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 comprised as an apparatus which performs etc.

  The electron gun 2 includes 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 for emitting an electron beam EB. 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 in the container 3 is provided on the wall of the case 6 on the container 3 side. An opening 6 b for attaching the connector 8 is provided on the side wall of the case 6. An uneven portion is provided on the inner wall of the case 6 around the opening 6b, so that the bonding strength with the insulating block 7 is ensured.

  The insulating block 7 is formed of an electrically insulating material such as an epoxy resin, for example, 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 truncated conical projection portion 7b projecting from the base portion 7a to the housing space S side in the container 3 through the opening 6a. . The base 7 a occupies most of the inside of the case 6 and is in contact with the inner walls of the case 6 on the opening 6 a side and the opening 6 b side. Moreover, the film 10 which has electroconductivity is affixed on the part which does not contact the inner wall of the case 6 in the base 7a. 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 in a state where the tip portion is located 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.

  At the base end of the connector 8, there is provided a power plug insertion port 8a that holds the tip of an external wiring extending from a power supply device (not shown). In addition, a pair of internal wirings 11 and 11 are connected to the tip of the connector 8. The internal wires 11, 11 extend from the tip of the connector 8 toward the center of the base 7a of the insulating block 7, bend from the center of the base 7a toward the protrusion 7b, and pass through the center of the protrusion 7b. It extends to the tip of 7b.

  The filament 9 is a member that emits electrons that become the electron beam EB. The filament 9 is attached to the tip of the protruding portion 7 b 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 portion 12 is electrically connected to one of the internal wirings 11, 11, and when a high voltage is applied to the filament 9, the high voltage is applied to the grid portion 12, so that the filament An electric field for extracting electrons from 9 is formed. Electrons drawn from the filament 9 are emitted as an electron beam EB from a hole formed in 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 manner as the internal wirings 11, 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 portion 12.

  The container 3 is formed in a cylindrical shape extending along the emission axis of the electron beam EB emitted from the filament 9, and is hermetically sealed in 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 the opening 6 a 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. A plurality of (for example, six) screw holes (not shown) are provided at the tip of the container 3 with a predetermined phase angle.

  An electromagnetic coil 15 and an electromagnetic coil 16 are disposed around the electron beam passage hole 14 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. With 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.

  More specifically, the electromagnetic coil 15 is affected by the mechanical center shift of each member constituting the passage path of the electron gun 2 and the electron beam EB, the residual magnetism of each component member, and the magnetic field around the installation location. This is an alignment coil for correcting the deviation of the electron beam EB with respect to the desired passage path (the central axis of the electron passage hole 14) caused by 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, and are used as necessary. Is done. On the other hand, the electromagnetic coil 16 is a focusing coil for collecting the electron beam EB emitted from the electron gun 2 to the electron beam emission window 24, and is composed of a cylindrical coil portion made of enameled wire and a magnetic circuit made of soft iron or the like. Is done. 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. Guided accurately to the center.

  As shown in FIG. 2, an exhaust pipe 17 is provided on the side of the container 3. The distal 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 device 1 is viewed from the direction of the emission axis of the electron beam EB. Thereby, interference with the power supply plug inserted into the connector 8 or external wiring and the vacuum pump 18 can be avoided, and the electron beam irradiation apparatus 1 can be reduced in size.

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

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

  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 distal end of the trunk portion 21a. Furthermore, the external thread part 21e for attaching the cap 23 is formed in the outer surface of the trunk | drum 21a. On the other hand, an insulating ring 25 and a metal ring 26 are provided on the flange portion 21b. The insulating ring 25 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. Further, the metal ring 26 has a male screw portion 26 a on its side surface, and is fixed to the flange portion 21 b via the insulating ring 25.

  In the flange portion 21b, six bolt holes 27 having a phase angle of about 60 ° are provided at positions outside the insulating ring 25 and the metal ring 26 (see FIG. 3). The pedestal 21 is inserted into each bolt hole 27 and screwed into the screw hole of the container 3 so that the through hole 21c and the electron beam passage hole 14 are concentric. 3 is firmly fixed to the tip. In addition, the groove | channel in which the O-ring 35 was installed is formed in the front-end | tip of the container 3, Thereby, the airtight sealing of the base 21 and the container 3 is maintained. Further, the pedestal 21 may be formed integrally with the container 3. In this case, it is not necessary to provide the O-ring 35 at the tip of the container 3.

  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 the base end side edge of the barrel portion 22a. A through hole 22c having a slightly smaller diameter than the through hole 21c of the pedestal 21 is formed at the center of the body portion 22a. 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 21 d of the base 21 with the through hole 22 c and the electron beam passage hole 14 being concentric.

  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 body 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 side surface of the threaded portion 23b is connected to the male screw portion 21e on the outer side surface of the trunk portion 21a. A corresponding female screw portion 23d is formed. The cap 23 is inserted into the opening 23c through the body portion 22a of the window substrate 22 and the electron beam emission window 24 by screwing the female screw portion 23d of the screwing portion 23b into the male screw portion 21e of the base 21. It is inserted into the base 21 in a state. Thereby, the flange 22b of the window substrate 22 is pressed against the bottom surface of the recess 21d of the pedestal 21 by the top 23a of the cap 23, and the window substrate 22 and the pedestal 21 are firmly fixed. Further, a groove in which an O-ring 36 is installed is formed on the bottom surface of the recess 21 d in the pedestal 21. Thereby, the hermetic seal between the window substrate 22 and the base 21 is maintained. The O-ring 35 and the O-ring 36 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 each of the O-rings 35 and 36 becomes substantially 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 with a thickness of about several μm to 10 μm, for example, with beryllium. 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 material of the electron beam exit window 24 may be any material having a high transmittance of the electron beam EB, and titanium, aluminum, or the like can be used in addition to the above-described beryllium.

  Next, the configuration of the current readout electrode 5 will be described.

  The current readout electrode 5 is a member for measuring the output of the electron beam EB emitted from the electron beam emission window 24 from the viewpoint of confirmation of operation performance of the electron beam irradiation apparatus 1 and maintenance. As shown in FIGS. 3 and 4, the current readout electrode 5 has a circular zenith portion 5a and a cylindrical screw portion 5b formed on one end side of the zenith portion 5a.

  In the center of the zenith 5a, an opening 5c having a diameter larger than the outer diameter of the body 22a of the window substrate 22 is formed. The inner diameter of the threaded portion 5b is substantially the same as the outer diameter of the insulating ring 25 and the metal ring 26. The inner surface of the threaded portion 5b corresponds to the male threaded portion 26a on the outer surface of the metal ring 26. A female screw portion 5d is formed. A lead wire (not shown) is attached to the screwing portion 5b. The lead wire is connected to an ammeter 29 (see FIG. 1) installed outside the electron beam irradiation apparatus 1.

  The current reading electrode 5 is formed by screwing the female screw part 5d of the screwing part 5b with the male screw part 26a of the metal ring 26 so that the electron beam emission window 24 is exposed from the opening part 5c. The ring 26 is fitted. Thereby, the current readout electrode 5 is disposed so as not to overlap the electron beam emission window 24 as seen from the emission axis direction of the electron beam EB and to surround the electron beam emission window 24. Further, since the metal ring 26 into which the current reading electrode 5 is fitted is fixed to the pedestal 21 via the insulating ring 25, the current reading electrode 5 and the pedestal 21, and the current reading electrode 5 and the container 3 are respectively mutually connected. It is in an electrically insulated state.

  With such a configuration of the current readout electrode 5, a portion of the zenith portion 5a of the current readout electrode 5 excluding the opening 5c functions as a readout end portion 5e into which a part of the electron beam EB flows. That is, among the electron beams EB emitted from the electron beam emission window 24, the electron beam EB that has returned to the electron beam emission window 24 side due to the influence of scattering or the like flows into the reading end portion 5e. The current generated by the electron beam EB flowing into the reading end portion 5e is sent to the ammeter 29 through the screwing portion 5b and a lead wire (not shown).

  As shown in FIG. 4, the reading end portion 5 e is disposed so as to protrude in the emission direction of the electron beam EB from the electron beam emission window 24, and the electron beam emission window 24 corresponds to the current reading electrode 5. It is located in the opening 5c. Thereby, the reading end portion 5e also functions as a protective member for preventing the irradiation object and other objects from hitting the electron beam exit window 24. This is particularly suitable when the irradiation object is transported from the direction intersecting the emission axis direction of the electron beam EB, for example, in the case of in-line electron beam irradiation.

  In addition, a suction tube 30 made of, for example, resin is attached to the current reading electrode 5. The suction tube 30 is inserted into an insertion port 5f provided in the threaded portion 5b of the current readout electrode 5, and the tip of the suction tube 30 is connected to the insertion port 5f at the zenith portion 5a of the current readout electrode 5. It is fixed in the opening 5g provided at the corresponding position. The proximal end of the suction tube 30 is connected to an oxygen concentration detector 31 installed outside the electron beam irradiation apparatus 1. A part of the atmospheric gas outside the electron beam exit window 24 is sent to the oxygen concentration detector 31 through the suction tube 30.

  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 is supplied to the filament 9 from the external power source via the internal wirings 11 and 11. Then, 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 of the electron beam EB is corrected by the electromagnetic coil 15, and then converged by the electromagnetic coil 16 and emitted outward from the electron beam emission window 24. The emitted electron beam EB is irradiated to an irradiation object such as a printed material flowing on the line in an atmosphere of an inert gas such as nitrogen gas.

  When the electron beam EB is emitted from the electron beam emission window 24, a part of the electron beam EB directed toward the irradiation object returns to the electron beam emission window 24 side due to the influence of scattering or the like, and the reading end portion 5 e of the current reading electrode 5. Flow into. The current generated when part of the electron beam EB flows is sent from the current reading electrode 5 to the ammeter 29, and the current value in the vicinity of the electron beam exit window 24 is monitored. Further, when the electron beam EB is emitted from the electron beam emission window 24, a part of the atmospheric gas outside the window unit 4 is sucked by the suction tube 30 attached to the current reading electrode 5. The sucked atmospheric gas is sent to the oxygen concentration detector 31 to monitor the oxygen concentration in the atmospheric gas. Generation of ozone in the atmospheric gas is effectively suppressed by starting emission of the electron beam EB after the oxygen concentration in the atmospheric gas becomes, for example, several hundred ppm or less.

  As described above, in the electron beam irradiation apparatus 1, the current reading electrode 5 is provided in the window unit 4 so as not to overlap the electron beam emission window 24 when viewed from the emission axis direction of the electron beam EB. The reading end portion 5e of the current reading electrode 5 is disposed so as to surround the electron beam emission window 24 when viewed from the emission axis direction of the electron beam EB. With this configuration, in the electron beam irradiation apparatus 1, among the electron beams EB emitted from the electron beam emission window 24, the current generated by the electron beam EB that has returned to the electron beam emission window 24 side due to scattering or the like is generated as an electron beam. Measurements can be made in the immediate vicinity of the exit window 24.

  Therefore, in this electron beam irradiation apparatus 1, the thickness of the electron beam exit window 24 varies with the lapse of operation time due to unevenness in the thickness of the electron beam exit window 24 and adhesion of scattered matter and dirt generated when the electron beam EB is irradiated onto the irradiation object. In consideration of the surface state of the electron beam exit window 24, the output (actual output) of the electron beam EB actually emitted from the electron beam exit window 24 can be accurately measured in real time. Further, the current reading electrode 5 does not block a part of the electron beam emission window 24, and a sufficient amount of the electron beam EB emitted from the electron beam emission window 24 can be secured.

  The current readout electrode 5 is attached to the window unit 4 via an insulating ring 25 having electrical insulation, and the window unit 4 and the container 3 are electrically insulated from each other. As described above, the current readout electrode 5 and the window unit 4 and the current readout electrode 5 and the container 3 are insulated, so that the current generated by the electron beam EB flowing into the window unit 4 and the container 3 and the current readout electrode 5 are reduced. It is possible to separate the current generated by the flowing electron beam EB. This improves the measurement accuracy of the actual output of the electron beam.

  Further, the reading end portion 5 e of the current reading electrode 5 protrudes in the emission direction of the electron beam EB from the electron beam emission window 24, and the electron beam emission window 24 is located in the opening 5 c of the current reading electrode 5. ing. Thereby, the current readout electrode 5 also functions as a protective member for preventing the irradiation object and other objects from hitting the electron beam exit window 24, and the foil-like electron beam exit window 24 is prevented from being damaged. In addition, a suction tube 30 is fixed to the reading end 5e. Therefore, it is possible to detect the component of the atmospheric gas in the very vicinity of the irradiation target, and to start emitting the electron beam EB after the oxygen concentration is reliably reduced. This effectively suppresses the generation of ozone in the atmospheric gas due to the emission of the electron beam EB.

[Second Embodiment]
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 FIGS. 5 and 6, the electron beam irradiation apparatus 40 according to the second embodiment deflects 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 the deflection coil 52. This is different from the first embodiment in which the electron beam EB is emitted from the window unit 4 at one point in that the electron beam EB is emitted linearly from the window unit 41. The window unit 41 is provided with a current readout electrode 42 having a configuration different from that of the first embodiment.

  First, the configuration of the window unit 41 in the electron beam irradiation apparatus 40 will be described. FIG. 7 is a plan view of the window unit viewed from the emission axis direction of the electron beam EB. FIG. 8 is an enlarged side sectional view of the window unit.

  As shown in FIGS. 7 and 8, the window unit 41 includes a casing 51, a window substrate 53, and an electron beam emission window 54. The casing 51 has a shape in which the width in the deflection direction of the electron beam EB (X direction in FIG. 5) increases from the proximal end side toward 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 51 b is formed on the base end side edge of the casing 51. The casing 51 is positioned so that the opening 51 a and the electron beam passage hole 14 are concentric, and is airtightly fixed to the tip of the container 3.

  A deflection coil 52 is provided in the vicinity of the flange portion 51 b 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 respectively attached to both ends of the deflection coil 52. The deflection coil 52 sandwiches the side wall on the proximal end side of the housing 51 with the support members 52a and 52a, thereby the housing 51. Are arranged so as to be close to one of the side walls orthogonal to the deflection direction. The deflection coil 52 deflects the traveling direction of the electron beam EB that has passed through the electron beam passage hole 14 linearly along the X direction based on a current value supplied from an external power source (not shown).

  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. The through holes 53a are arranged in a line at a predetermined interval along the deflection direction of the electron beam EB. 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. As in the first embodiment, the electron beam exit window 54 is formed in a rectangular shape having a thickness of about several μm to 10 μm, for example, with beryllium. 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. A groove in which an O-ring 60 is installed is formed at the tip of the casing 51. Thereby, the hermetic sealing between the window substrate 53 and the housing 51 is maintained.

  Next, the configuration of the current read electrode 42 will be described.

  As shown in FIGS. 7 and 8, the current reading electrode 42 includes two end members 42a having a U-shape when viewed from the emission axis direction of the electron beam EB, and six intermediate members 42b having a linear shape. It is constituted by. The end members 42a are respectively arranged at the ends of the electron beam EB in the deflection direction of the electron beam EB on the window substrate 53, and when viewed from the electron beam EB emission axis direction, Of these, three sides are surrounded except for a portion facing the inner side in the deflection direction of the electron beam EB. The intermediate member 42b is disposed at the edge of the window substrate 53 between the end members 42a and 42a, and is arranged along the deflection direction of the electron beam EB so as to sandwich the three electron beam emission windows 54 located on the center side. It is extended. Further, the end member 42 a and the intermediate member 42 b and the intermediate members 42 b and 42 b are spaced apart with the same width as that of the partition groove 53 b of the window substrate 53. Lead wires (not shown) are attached to the end members 42a and the intermediate members 42b. The lead wire is connected to an ammeter 29 (see FIG. 5) installed outside the electron beam irradiation apparatus 40.

  Due to the arrangement of the end member 42 a and the intermediate member 42 b, the current reading electrode 42 has a rectangular ring shape having the same dimensions as the window substrate 53 as a whole, and a rectangular opening formed at the center of the current reading electrode 42. Each electron beam emission window 54 is exposed from 42c. The current reading electrode 42 is disposed so as not to overlap each electron beam emission window 54 when viewed from the emission axis direction of the electron beam EB, and surrounds the electron beam emission window 54, and the tip of the current reading electrode 42 is arranged. Of the portion, the portion excluding the opening 42c functions as a reading end portion 42d into which a part of the electron beam EB flows.

  Similarly to the first embodiment, the reading end portion 42d is disposed so as to protrude in the emission direction of the electron beam EB from each electron beam emission window 54, and each electron beam emission window 54 is an opening of the current reading electrode 42. It is located in the part 42c. Further, for example, a resin suction pipe 55 is attached to one end member 42a. The suction tube 55 is inserted into an insertion port 42e provided on the side wall of the end member 42a, and the tip of the suction tube 55 is located at a position corresponding to the insertion port 42e on the distal end side of the end member 42a. It is fixed in the provided opening 42f. The proximal end of the suction tube 55 is connected to an oxygen concentration detector 31 installed outside the electron beam irradiation device 40 (see FIG. 5).

  An insulating member 56 having electrical insulation is provided between the current reading electrode 42 and the window substrate 53. The insulating member 56 is made of, for example, polytetrafluoroethylene, and includes two end insulating members 56a and six intermediate insulating members 56b. Each of the end insulating member 56a and the intermediate insulating member 56b is fixed to the edge of the window substrate 53 with the same arrangement as the end member 42a and the intermediate member 42b.

  The end member 42a and the intermediate member 42b are fixed to the edge of the window substrate 53 through the end insulating member 56a and the intermediate insulating member 56b. Therefore, the end member 42a and the intermediate member 42b and the window substrate 53, and the end member 42a and the intermediate member 42b and the container 3 are electrically insulated from each other. Further, since the end member 42a and the intermediate member 42b and the intermediate members 42b and 42b are spaced apart from each other with the same width as the partition groove 53b of the window substrate 53, they are also electrically connected to each other. It is in an insulated state.

  In such an electron beam irradiation apparatus 40 as well, in the same manner as in the first embodiment, in the window unit 41, the current readout electrode 42 is provided so as not to overlap the electron beam emission window 54 when viewed from the emission axis direction of the electron beam EB. Is provided. The reading end portion 42d of the current reading electrode 42 is disposed so as to surround the electron beam emission window 54 when viewed from the emission axis direction of the electron beam EB. Therefore, also in the electron beam irradiation apparatus 40, among the electron beams EB emitted from the electron beam emission window 54, a current generated by the electron beam EB returned to the electron beam emission window 54 side due to scattering or the like is generated in the electron beam emission window 54. Measurement can be performed in the very vicinity, and the actual output of the electron beam EB can be accurately measured in real time. Further, the current reading electrode 42 does not block a part of the electron beam emission window 54, and a sufficient emission amount of the electron beam EB from the electron beam emission window 54 can be secured.

  Further, the current reading electrode 42 is electrically insulated from the window unit 41 and the container 3. Therefore, the current generated by the electron beam EB flowing into the window unit 41 and the container 3 can be separated from the current generated by the electron beam EB flowing into the current reading electrode 42. Further, the end member 42a and the intermediate member 42b constituting the current reading electrode 42 are also electrically insulated from each other. Thereby, the current generated by the electron beam EB flowing into each end member 42a and the intermediate member 42b can be separated. This makes it possible to measure the actual output (output distribution) of the electron beam EB for each electron beam exit window 54.

  Furthermore, since the reading end portion 42 d of the current reading electrode 42 protrudes in the emission direction of the electron beam EB from the electron beam emission window 54, the current reading electrode 42 also functions as a protective member for the electron beam emission window 54. The foil-shaped electron beam emission window 54 is prevented from being damaged. Further, since the suction pipe 55 is fixed to the reading end portion 42d, it is possible to detect the component of the atmospheric gas such as monitoring the oxygen concentration in the very vicinity of the irradiation object.

  The present invention is not limited to the above embodiment. For example, in the first embodiment, the reading end portion 5e of the current reading electrode 5 is protruded in the emission direction of the electron beam EB from the electron beam emission window 24. Instead, as shown in FIG. The electron beam emission window 24 may be protruded in the emission direction of the electron beam EB from the reading end portion 5e. In this case, since the electron beam emission window 24 can be brought closer to the irradiation object, it is possible to irradiate the irradiation object with a sufficient dose of electron beam. The same applies to the second embodiment. That is, as shown in FIG. 10, the electron beam emission window 54 may be projected in the emission direction of the electron beam EB from the end member 42 a and the intermediate member 42 b.

  Further, feedback may be applied to the control unit (not shown) of the electron gun 2 so that the current value detected by the current readout electrodes 5 and 42 is constant. In this way, it is possible to stabilize the output of the electron beam EB emitted from the electron beam emission windows 24 and 54.

It is a sectional side view which shows the structure of the electron beam irradiation apparatus which concerns on 1st Embodiment of this invention. It is the II-II sectional view taken on the line in FIG. It is a top view of the window unit seen from the output axis direction of the electron beam EB. It is an expanded side sectional view of a window unit. It is a sectional side view which shows the structure of the electron beam irradiation apparatus which concerns on 2nd Embodiment of this invention. It is the VI-VI sectional view taken on the line in FIG. It is a top view of the window unit seen from the output axis direction of the electron beam EB. It is an expanded side sectional view of a window unit. It is an expansion side sectional view of the window unit concerning a modification. It is an expanded sectional side view of the window unit which concerns on another modification.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,40 ... Electron beam irradiation apparatus, 2 ... Electron gun, 3 ... Container, 4 ... Window unit, 5,42 ... Current reading electrode, 5e, 42d ... Reading end part, 9 ... Filament (electron emission member), 14 ... Electron beam passage hole, 24, 54 ... electron beam exit window, 25 ... insulating ring (member having electrical insulation), 30, 55 ... suction tube, 56 ... insulating member (member having electrical insulation), EB ... electron line.

Claims (6)

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 window unit having an electron beam exit window that is fixed to the container so as to close the electron beam passage hole and emits the electron beam that has passed through the electron beam passage hole to the outside of the container;
An electron beam irradiation apparatus comprising: a current readout electrode provided in the window unit and disposed so as not to overlap the electron beam emission window when viewed from the electron beam emission axis direction.   2. The electron beam irradiation apparatus according to claim 1, wherein the current readout electrode is coupled to the window unit through a member having electrical insulation.   3. The electron beam according to claim 1, wherein the current reading electrode is provided with a reading end portion so as to surround the electron beam emission window when viewed from the emission axis direction of the electron beam. Irradiation device.   The electron beam irradiation apparatus according to claim 3, wherein the electron beam emission window protrudes in an emission direction of the electron beam from the reading end portion.   4. The electron beam irradiation apparatus according to claim 3, wherein the reading end portion protrudes in the electron beam emission direction from the electron beam emission window.   6. The electron according to claim 1, wherein a tip of a suction tube that sucks a part of the atmospheric gas outside the electron beam exit window is fixed to the current readout electrode. X-ray irradiation device.

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