JP7391373B2 - Beam image acquisition method for electron beam irradiation equipment - Google Patents

Description

The present invention relates to a beam image acquisition method for an electron beam irradiation device.

For example, in the electron beam irradiation device described in Patent Document 1, the inside of the chamber is kept in a vacuum by sealing the opening window of the chamber with window foil. The electron beam generated by the filament passes through the window foil of the opening window and is emitted to the outside of the chamber.

Incidentally, in an electron beam irradiation device, a beam image is acquired in order to confirm whether the electron beam is appropriately emitted to a targeted position. In acquiring an electron beam image, photosensitive paper that changes color to a predetermined color in response to the light of the electron beam is generally used. When acquiring a beam image, photosensitive paper is placed overlapping the outside surface of the window foil. When the electron beam transmitted through the window foil reaches the photosensitive paper, the portion of the photosensitive paper irradiated with the electron beam changes to a photosensitive color. Thereby, a beam image of the electron beam can be obtained. Here, it is necessary to mark the reference position on the photosensitive paper, and in the past, the photosensitive paper was placed over the outside surface of the window foil, and the marks were directly placed on the photosensitive paper with a pen or the like. I was wearing it.

Japanese Patent Application Publication No. 10-319200

In the method of marking on photosensitive paper as described above, there is a risk that the window foil on the back side of the photosensitive paper may be damaged by the pressure of writing with a pen or the like. For this reason, it is necessary to mark the photosensitive paper in such a way that the load is not applied to the paper as much as possible, which makes the work of marking the photosensitive paper extremely difficult.

The present invention has been made to solve the above problems, and its purpose is to provide a beam image acquisition method for an electron beam irradiation device that can prevent damage to the window foil when marking on photosensitive paper. It is in.

A beam image acquisition method of an electron beam irradiation device that solves the above problem is a beam image acquisition method that acquires a beam image of the electron beam in an electron beam irradiation device that transmits the electron beam through a window foil of an aperture window and emits it to the outside. The method includes placing photosensitive paper overlappingly on the external surface of the window foil, irradiating the photosensitive paper with a laser beam output from a laser emitting device from the side opposite to the window foil, and a first step of marking by a color change of the photosensitive paper due to irradiation with a laser beam, and a step of irradiating the electron beam onto the photosensitive paper through the window foil, and causing a color change of the photosensitive paper due to the irradiation of the electron beam; and a second step of acquiring a beam image of the electron beam.

According to the above aspect, marks are made on the photosensitive paper using laser light. Therefore, since it is possible to mark the photosensitive paper from a distant position, it is possible to mark the photosensitive paper without applying any load to the window foil on the back side of the photosensitive paper. This prevents damage to the window foil when marking the photosensitive paper.

In the beam image acquisition method for an electron beam irradiation device, the photosensitive paper includes a sheet-like base material and a photosensitive layer formed on a surface of the base material opposite to the window foil, In one step, a mark is made by color change of the photosensitive layer due to irradiation with the laser beam.

According to the above aspect, the photosensitive layer of the photosensitive paper is formed on the external surface of the base material (the surface opposite to the window foil). Therefore, it is possible to suitably mark the photosensitive layer of the photosensitive paper with laser light irradiated onto the photosensitive paper from the outside (the side opposite to the window foil).

In the above beam image acquisition method for an electron beam irradiation device, the photosensitive paper has the photosensitive layer as a first photosensitive layer and a second photosensitive layer on the surface of the base material on the window foil side, and In this step, a beam image of the electron beam is obtained by color change of the second photosensitive layer due to irradiation with the electron beam.

According to the above aspect, the photosensitive paper has photosensitive layers on both sides. On the other hand, if only the surface of photosensitive paper opposite to the window foil (external surface) is used as a photosensitive layer, the electron beam that has passed through the base material of the photosensitive paper will reach the photosensitive layer. , the electron beam image may become blurred. In this regard, by providing a photosensitive layer (second photosensitive layer) also on the window foil side surface of the photosensitive paper, a beam image with a clear outline can be obtained in the second photosensitive layer.

In the beam image acquisition method for an electron beam irradiation device, the photosensitive paper includes a light shielding layer that blocks transmission of the laser beam between the first photosensitive layer and the second photosensitive layer.
According to the above aspect, the light shielding layer can prevent the laser light irradiated from the first photosensitive layer side from reaching the second photosensitive layer. Thereby, a beam image of the electron beam can be more appropriately acquired in the second photosensitive layer.

According to the beam image acquisition method for an electron beam irradiation apparatus of the present invention, it is possible to prevent damage to the window foil when making marks on photosensitive paper.

FIG. 1 is a schematic configuration diagram of an electron beam irradiation device in an embodiment. FIG. 3 is a schematic diagram showing how photosensitive paper is attached. A cross-sectional view of photosensitive paper. FIG. 3 is a schematic configuration diagram showing an electron beam emission site in an electron beam irradiation device of the same type.

An embodiment of a beam image acquisition method for an electron beam irradiation device will be described below with reference to the drawings. Note that in the drawings, a part of the configuration may be exaggerated or simplified for convenience of explanation. Furthermore, the dimensional ratio of each part may also differ from the actual size.

The electron beam irradiation device 10 of this embodiment shown in FIG. 1 is a scanning type electron beam irradiation device. The electron beam irradiation device 10 includes a filament 11 made of, for example, tungsten that emits thermionic electrons. The filament 11 emits electrons by heating itself based on the power supply from the filament power supply 12. The filament 11 is provided on the upper end side of the acceleration tube 13.

The acceleration tube 13 has a cylindrical shape with a closed upper end where the filament 11 is placed. The accelerating tube 13 has a plurality of accelerating electrodes 14 arranged in parallel in the axial direction of the accelerating tube 13. The accelerating electrode 14 generates an electric field that converges the electrons emitted from the filament 11 and accelerates them downward based on the power supply from the accelerating electrode power source 15. That is, in the accelerating tube 13, the electric field generated at the accelerating electrode 14 causes an electron flow directed downward in the tube axis direction, that is, an electron beam e. A scanning tube 16 is connected to the acceleration tube 13 at its lower end. The acceleration tube 13 and the scanning tube 16 communicate with each other through an internal space 17, and the electron beam e advances from the accelerating tube 13 toward the scanning tube 16 in the internal space 17.

The scanning tube 16 has a shape that is narrow at the upper end and widens toward the bottom. The scan tube 16 is provided with a scan coil 18 at its narrow upper end. The scanning coil 18 deflects the direction of the electron beam e generated by the accelerator tube 13 based on the energization thereof, that is, scans the electron beam e. For example, a substantially rectangular opening window portion 19 is provided at the lower end of the scanning tube 16, and a substantially rectangular window foil 20 is attached to the opening window portion 19. The window foil 20 seals the opening window portion 19 while allowing the electron beam e to pass therethrough. In other words, the internal space 17 spanning the acceleration tube 13 and the scanning tube 16 is configured as a closed space. The internal space 17 is kept in a vacuum state, for example, by driving a vacuum pump 21 connected to the scanning tube 16, at least during the period when the electron beam e is generated.

The filament power source 12, accelerating electrode power source 15, scanning coil 18, and vacuum pump 21 described above are controlled by a control device 22. The control device 22 adjusts the output of the electron beam e through the power supplies 12 and 15, controls the scanning of the electron beam e through the scanning coil 18, and controls the internal space 17 of the acceleration tube 13 and the scanning tube 16 through the vacuum pump 21. Perform vacuum adjustment.

Then, the electron beam e emitted through the window foil 20 attached to the opening window portion 19 is irradiated onto the irradiated object 24 that is transported in the transport direction x by the transport device 23, for example. Perform predetermined processing. In this case, the electron beam irradiation device 10 is arranged such that the longitudinal direction of the substantially rectangular opening window 19 faces the direction y perpendicular to the transport direction of the transport device 23, and the electron beam irradiation device 10 is arranged so that the longitudinal direction of the approximately rectangular opening window 19 faces the direction y perpendicular to the transport direction y of the transport device 23. A predetermined scan of e is performed, and a substantially rectangular irradiation area A corresponding to the opening window portion 19 is irradiated. The effect of irradiating the object 24 with the electron beam e can be expected to be, for example, improving the properties of the material, adding functionality, and sterilizing/sterilizing the material.

Next, a method of acquiring a beam image of the electron beam (electron beam) e will be explained.
FIG. 2 shows a state in which a photosensitive paper 25 for obtaining a beam image of the electron beam e is attached to the opening window 19 from which the electron beam e is emitted. Further, FIG. 3 shows the layer structure of the photosensitive paper 25 used in this embodiment.

As shown in FIG. 3, the photosensitive paper 25 includes a sheet-like base material 30 made of paper, a first photosensitive layer 31 formed on one main surface side of the base material 30, and a first photosensitive layer 31 formed on the other main surface side of the base material 30. It includes a second photosensitive layer 32 formed on the surface side, and a light shielding layer 33 formed between the base material 30 and the first photosensitive layer 31. The first photosensitive layer 31 and the second photosensitive layer 32 are made of a photosensitive material that changes color when irradiated with light. The light shielding layer 33 is made of a material through which light does not easily pass.

When acquiring a beam image of the electron beam e, first, the photosensitive paper 25 is placed so that it overlaps the lower surface of the window foil 20 (the external surface of the window foil 20) assembled in the opening window 19 in a manner that it closes it. Place it in For example, when the window foil 20 is attached to the peripheral edge of the opening window 19 using the mounting frame 19a, the peripheral edge of the photosensitive paper 25 is inserted into the gap between the window foil 20 and the mounting frame 19a, and the photosensitive paper 25 is 25 is held so that it does not fall off. Note that the mounting frame 19a is fixed to the lower end (the end on the output side) of the scanning tube 16 by a bolt (not shown). Further, at this time, the photosensitive paper 25 is arranged so that the second photosensitive layer 32 faces the window foil 20 and the first photosensitive layer 31 faces outside. Note that in this embodiment, one sheet of photosensitive paper 25 is used that covers the entire surface of the window foil 20.

Thereafter, a step (first step) of marking the photosensitive paper 25 placed on the outside surface of the window foil 20 from the outside (first photosensitive layer 31) side is performed. In this step, a laser emitting device 40 is used to mark the photosensitive paper 25. That is, the first photosensitive layer 31 is irradiated with the laser beam L from the laser emitting device 40, and a mark is made by the color change of the first photosensitive layer 31 due to the irradiation with the laser beam L. Note that an example of the laser light L used for applying the marks is an ultraviolet laser, and in this case, the first photosensitive layer 31 is made of a material that changes color upon receiving ultraviolet light.

FIG. 4 shows an example of marks applied to the photosensitive paper 25 in the above process. In the example shown in the figure, a mark M1 indicating the range of the opening window 19 (in this embodiment, the range of the opening 19b of the mounting frame 19a) and a mark M2 indicating the center position of the range are formed by the laser beam L. , attached to the first photosensitive layer 31. Note that the mark M2 is placed based on a mark indicating the center position of the opening window portion 19 provided on the scanning tube 16 and the mounting frame 19a.

Furthermore, in the above process, the laser light L irradiated from the first photosensitive layer 31 side is blocked by the light shielding layer 33 of the photosensitive paper 25, making it difficult for the laser light L to reach the second photosensitive layer 32. . Thereby, the color change of the second photosensitive layer 32 is less likely to occur with the laser light L in this step.

Next, the electron beam irradiation device 10 is activated, and irradiation is performed by, for example, predetermined scanning of the electron beam e to obtain a beam image of the electron beam e (second step). As a result, the electron beam e that has passed through the window foil 20 is irradiated onto the photosensitive paper 25, and the portion of the second photosensitive layer 32 facing the window foil 20 that is irradiated with the electron beam e changes color. This makes it possible to obtain the current beam image of the irradiation area of the electron beam e, the reference irradiation position, and the like. As a result, a beam image of the electron beam e is obtained.

Based on the beam image and marks M1 and M2 drawn on the photosensitive paper 25, it becomes possible to check whether the electron beam e is properly emitted to the targeted position, and if necessary, The scanning mode of e is adjusted. After this adjustment, the object 24 to be irradiated with the electron beam e is properly irradiated.

The effects of this embodiment will be explained.
(1) Laser light L emitted from the laser emitting device 40 is irradiated from the outside side (first photosensitive layer 31 side) onto the photosensitive paper 25 placed over the outside surface of the window foil 20, and the laser beam L is emitted from the outside side (first photosensitive layer 31 side) Marks M1 and M2 are attached by color change of the first photosensitive layer 31 due to irradiation with the light L. According to this aspect, since it is possible to mark the marks M1 and M2 on the photosensitive paper 25 from a separate position, the marks M1 and M2 can be placed on the photosensitive paper 25 without applying any load to the window foil 20 on the back side of the photosensitive paper 25. It becomes possible to attach M1 and M2. This can prevent damage to the window foil 20 when markings M1 and M2 are placed on the photosensitive paper 25.

(2) The photosensitive paper includes a sheet-like base material 30 and a first photosensitive layer 31 formed on the surface of the base material 30 opposite to the window foil 20. Then, in the step of marking M1 and M2 with the laser beam L (first step), the marks are formed by color change of the first photosensitive layer 31 due to irradiation with the laser beam L. Thereby, it becomes possible to suitably mark the first photosensitive layer 31 with the laser beam L irradiated onto the photosensitive paper 25 from the outside (the side opposite to the window foil 20).

(3) The photosensitive paper 25 includes the second photosensitive layer 32 on the surface of the base material 30 on the window foil 20 side, and the first photosensitive layer 31 on the opposite (external side) surface. Then, in the step (second step) of irradiating the photosensitive paper 25 with the electron beam e to obtain a beam image, a beam image of the electron beam e is obtained by the color change of the second photosensitive layer 32 irradiated with the electron beam e. do.

According to the above embodiment, the photosensitive paper 25 has the first and second photosensitive layers 31 and 32 on both sides. On the other hand, when the photosensitive layer is only the external surface of the photosensitive paper 25 (first photosensitive layer 31 only), the electron beam e transmitted through the base material 30 of the photosensitive paper 25 is directed to the first photosensitive layer 31. Since the electron beam e is irradiated and a beam image is obtained on the first photosensitive layer 31, there is a possibility that the beam image of the electron beam e becomes blurred. In this regard, by providing a photosensitive layer (second photosensitive layer 32) also on the window foil 20 side of the photosensitive paper 25, a beam image with a clear outline can be obtained in the second photosensitive layer 32.

(4) The photosensitive paper 25 includes a light shielding layer 33 that blocks transmission of the laser beam L between the first photosensitive layer 31 and the second photosensitive layer 32. According to this aspect, the light shielding layer 33 can prevent the laser light L irradiated from the first photosensitive layer 31 side from reaching the second photosensitive layer 32 . Thereby, a beam image of the electron beam e can be more appropriately acquired on the second photosensitive layer 32.

This embodiment can be modified and implemented as follows. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
- The temporal order of the first step of marking marks M1 and M2 on the photosensitive paper 25 by irradiation with the laser beam L and the second step of drawing a beam image on the photosensitive paper 25 by irradiation with the electron beam e is the same as in the above embodiment. The method is not limited to this, and the first step may be performed after the second step.

- The type of laser beam L that applies marks to the first photosensitive layer 31 of the photosensitive paper 25 is not limited to the above embodiment, and may be a laser beam in the visible region other than an ultraviolet laser, for example.
- In the photosensitive paper 25 of the above embodiment, the light shielding layer 33 is formed between the base material 30 and the first photosensitive layer 31; however, the light shielding layer 33 is not limited to this, and the light shielding layer 33 is formed between the second photosensitive layer 32 and the base material 30. A layer may be formed.

- The light shielding layer 33 may be omitted from the photosensitive paper 25 of the above embodiment.
- The second photosensitive layer 32 may be omitted from the photosensitive paper 25 of the above embodiment. In this case, in the step (second step) of irradiating the photosensitive paper 25 with the electron beam e to obtain a beam image, the electron beam e passes through the base material 30 and is irradiated onto the first photosensitive layer 31. A beam image can be obtained using the photosensitive layer 31. Note that if the second photosensitive layer 32 is omitted, the light shielding layer 33 is not necessary.

- The first photosensitive layer 31 and the light shielding layer 33 may be omitted from the photosensitive paper 25 of the above embodiment. In this case, in the step (first step) of marking marks M1 and M2 on the photosensitive paper 25 with the laser beam L, the laser beam L passes through the base material 30 and is irradiated onto the second photosensitive layer 32. Marks M1 and M2 can be attached to the.

- For the base material 30 of the photosensitive paper 25, in addition to paper made of vegetable fibers, for example, a sheet-shaped synthetic resin material or the like can be used.
- In the above embodiment, the photosensitive paper 25 is used to cover the entire surface of the window foil 20, but the present invention is not limited to this, and a photosensitive paper having a size that covers a specific portion where a beam image is to be obtained may be used.

- In the above embodiment, a beam image of the electron beam e is obtained using one sheet of photosensitive paper 25 that covers the entire surface of the window foil 20, but the invention is not limited to this. They may be arranged in the plane direction so as to cover the entire surface of the window foil 20, or to cover a specific portion where a beam image is to be obtained. According to this, each photosensitive paper can be made small.

- In the electron beam irradiation device 10 of the above embodiment, the opening direction of the opening window portion 19 was configured to be downward, that is, the traveling direction of the electron beam e was set to be downward. It may be.

- Applied to a scanning type electron beam irradiation device 10 that forms an electron beam e from electrons emitted from a single filament 11 and scans it with a scanning coil 18 to irradiate the irradiation area A, but it corresponds to the irradiation area. The present invention may also be applied to an area type electron beam irradiation device using a plurality of filaments and omitting a scanning coil.

DESCRIPTION OF SYMBOLS 10... Electron beam irradiation device 19... Opening window part 20... Window foil 25... Photosensitive paper 30... Base material 31... First photosensitive layer 32... Second photosensitive layer 33... Light shielding layer 40... Laser emission device e... Electron beam L... Laser light M1, M2... mark

Claims (4)

A beam image acquisition method for acquiring a beam image of an electron beam in an electron beam irradiation device that transmits an electron beam through a window foil of an opening window and emits it to the outside, the method comprising:
A photosensitive paper is placed over the outside surface of the window foil, and a laser beam output from a laser emitting device is irradiated onto the photosensitive paper from the side opposite to the window foil, so that the irradiation with the laser beam a first step of marking by changing the color of the photosensitive paper;
a second step of irradiating the photosensitive paper with the electron beam through the window foil and obtaining a beam image of the electron beam by changing the color of the photosensitive paper due to the irradiation with the electron beam;
A beam image acquisition method for an electron beam irradiation device equipped with. The photosensitive paper includes a sheet-like base material, and a photosensitive layer formed on a surface of the base material opposite to the window foil,
2. The beam image acquisition method for an electron beam irradiation apparatus according to claim 1, wherein in the first step, a mark is made by color change of the photosensitive layer due to irradiation with the laser beam. The photosensitive paper has the photosensitive layer as a first photosensitive layer and a second photosensitive layer on the surface of the base material on the window foil side,
3. The beam image acquisition method for an electron beam irradiation apparatus according to claim 2, wherein in the second step, a beam image of the electron beam is acquired by color change of the second photosensitive layer due to irradiation with the electron beam. 4. The beam image acquisition method for an electron beam irradiation apparatus according to claim 3, wherein the photosensitive paper includes a light shielding layer that blocks transmission of the laser beam between the first photosensitive layer and the second photosensitive layer.