Electron beam irradiation device

Abstract

To provide an electron beam irradiation device that can suppress damage of a protection cover.SOLUTION: An electron beam irradiation device 10 comprises: a scanning tube 16 that has an opening window part 19 which an electron beam passes through; a window foil 20 that is provided to close the opening window part 19, and makes the electron beam transmit; a removable protection cover 50 that covers an outer side of the window foil 20; a flow channel 35 in which a face 20a on an outer side of the scanning tube 16 in the window foil 20 is exposed, and cooling gas for cooling the window foil 20 flows; a measurement unit 61 that measures pressure inside the flow channel 35; and a control device 41 that detects whether the protection cover 50 is in an attached state on the basis of a measurement result of the measurement unit 61, and permits external emission of the electron beam via the window foil 20 as a condition that the protection cover 50 is in a non-attached state. The flow channel 35 has an exhaust port 34 through which the electron beam passing through the opening window part 19 passes. The cooling gas is exhausted outside the flow channel 35 from the exhaust port 34. The protection cover 50 is configured to cover the face 20a of the window foil 20 by covering the exhaust port 34.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an electron beam irradiation device. [Background technology]

[0002] For example, the electron beam irradiation device described in Patent Document 1 includes a housing having an opening window through which an electron beam from an electron beam generating unit passes, a window foil that is provided to cover the opening window and transmits the electron beam from inside the housing to outside the housing, and a removable protective cover that covers the outside side of the window foil. During normal use of the electron beam irradiation device, the protective cover is removed from the housing, and the electron beam emitted to the outside of the housing through the window foil is irradiated onto an object to be irradiated. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6343154 Summary of the Invention [Problem to be solved by the invention]

[0004] In the electron beam irradiation device as described above, if electron beam irradiation is started without removing the protective cover, the protective cover may be irradiated with the electron beam and damaged. [Means for solving the problem]

[0005] An electron beam irradiation device that solves the above problem is an electron beam irradiation device comprising: an electron beam generating unit that generates an electron beam; a housing unit having an opening window through which the electron beam passes; a window foil that is arranged to cover the opening window and allows the electron beam to pass from inside the housing unit to the outside of the housing unit; and a removable protective cover that covers the exterior side of the window foil, wherein the electron beam irradiation device comprises: a flow path that exposes the exterior side of the housing unit of the window foil and through which a cooling gas for cooling the window foil passes; a measurement unit that measures the pressure within the flow path or the flow rate of the cooling gas passing through the flow path; and a control unit that detects whether the protective cover is in an attached state based on the measurement result of the measurement unit and allows the emission of the electron beam through the window foil on the condition that the protective cover is not in an attached state, wherein the flow path has an exhaust port through which the electron beam that has passed through the opening window passes, and the cooling gas is exhausted to the outside of the flow path from the exhaust port, and the protective cover covers the exterior side of the window foil of the housing unit by covering the exhaust port.

[0006] According to this configuration, when cooling gas is supplied to the flow path, the amount of cooling gas discharged from the outlet to the outside of the flow path is greater when the protective cover is not attached than when the protective cover is attached. Therefore, the pressure in the flow path when the protective cover is attached is higher than the pressure in the flow path when the protective cover is removed. Also, the flow rate of cooling gas passing through the flow path when the protective cover is attached is lower than the flow rate of cooling gas passing through the flow path when the protective cover is not attached. Therefore, it is possible to detect whether the protective cover is attached or not based on the pressure in the flow path or the flow rate of cooling gas passing through the flow path measured by the measuring unit.

[0007] The control unit allows the emission of the electron beam through the window foil on the condition that the protective cover is not attached. Therefore, if the protective cover is left in the unattached state, the control unit does not allow the emission of the electron beam. This makes it possible to prevent damage to the protective cover caused by irradiation of the electron beam by the protective cover.

[0008] The above electron beam irradiation device further includes a notification unit that issues a notification based on a detection result by the control unit as to whether or not the protective cover is in an attached state. According to this configuration, the notification unit can notify based on the detection result of the control unit, which makes it easier for the operator to recognize whether or not emission of the electron beam is permitted, thereby improving operability. Effect of the Invention

[0009] According to the electron beam irradiation device of the present invention, damage to the protective cover can be suppressed. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic configuration diagram of an electron beam irradiation device according to an embodiment. [Diagram 2] FIG. 2 is a schematic configuration diagram showing a part of the electron beam irradiation device in the same embodiment. [Diagram 3] FIG. 2 is a schematic configuration diagram showing a part of the electron beam irradiation device in the same embodiment with a protective cover attached. [Figure 4] FIG. 13 is a schematic configuration diagram showing a part of an electron beam irradiation device in a modified example with a protective cover attached. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of an electron beam irradiation apparatus will be described with reference to the drawings. Note that in the drawings, for the sake of convenience, some of the configuration may be shown in an exaggerated or simplified manner. Furthermore, the dimensional ratios of each part may differ from the actual ratios.

[0012] 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 thermoelectrons. The filament 11 corresponds to an electron beam generating unit that generates an electron beam e. The filament 11 emits electrons by heating itself based on power supply from a filament power supply 12. The filament 11 is provided on the upper end side of an accelerating tube 13.

[0013] The acceleration tube 13 is cylindrical with a closed upper end where the filament 11 is disposed. The acceleration tube 13 has a plurality of acceleration electrodes 14 arranged in parallel in the tube axis direction of the acceleration tube 13. The acceleration electrodes 14 generate an electric field that converges and accelerates the electrons emitted from the filament 11 downward based on the power supply from the acceleration electrode power supply 15. That is, in the acceleration tube 13, an electron flow that faces downward in the tube axis direction, that is, an electron beam e, is generated by the electric field generated by the acceleration electrodes 14. The acceleration tube 13 is connected to a lower end of the scanning tube 16. 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 acceleration tube 13 to the scanning tube 16 in the internal space 17. The scanning tube 16 corresponds to a housing part of the electron beam irradiation device 10.

[0014] The scan tube 16 is narrow at the upper end and widens downward. A scan coil 18 is provided at the narrow upper end of the scan tube 16. The scan coil 18 deflects the direction of the electron beam e generated by the acceleration tube 13, i.e., scans the electron beam e, based on the current passing through the scan coil 18 itself.

[0015] (Configuration of window foil 20) As shown in Fig. 1 and Fig. 2, a substantially rectangular opening window 19 is provided at the lower end of the scanning tube 16, i.e., the end on the emission side. A substantially rectangular window foil 20 is attached to the opening window 19. The window foil 20 is made of, for example, a very thin metal foil. For example, a titanium-based metal material is used as the material for the window foil 20. The window foil 20 is one size larger than the opening window 19 and is provided so as to cover the opening window 19.

[0016] The window foil 20 is fixed in a manner that it is sandwiched between the lower end of the scan tube 16 and a mounting frame 19a fixed to the peripheral edge of the opening window portion 19. The mounting frame 19a is fixed to the lower end of the scan tube 16 by bolts (not shown) or the like. The mounting frame 19a has an opening 19b for passing the electron beam e that has passed through the window foil 20.

[0017] The window foil 20 allows the electron beam e to pass through while sealing the open window portion 19. In other words, the internal space 17 spanning the accelerating tube 13 and the scan tube 16 is a sealed space. The internal space 17 is made into a vacuum state by, for example, driving a vacuum pump 21 connected to the scan tube 16, at least during the period during which the electron beam e is generated.

[0018] (Configuration of cooling gas discharge device 31) 2, the electron beam irradiation device 10 may have a cooling gas discharge device 31. The cooling gas discharge device 31 is disposed, for example, so as to surround the outer periphery of the open window portion 19 and the mounting frame 19a. The cooling gas discharge device 31 has at least one discharge port 32. For example, the cooling gas discharge device 31 has a plurality of discharge ports 32 on the outer periphery of the mounting frame 19a.

[0019] The cooling gas discharge device 31 discharges a cooling gas for cooling the window foil 20 from a discharge port 32. In the drawing, the cooling gas is illustrated by a dashed arrow. The cooling gas is, for example, air. The cooling gas is not limited to air, and may be, for example, a gas such as nitrogen gas.

[0020] (Configuration of guide member 33) The electron beam irradiation device 10 may have a guide member 33 that guides the cooling gas discharged from the discharge port 32 to the window foil 20. The guide member 33 has a shape that is slightly larger than the opening 19b of the mounting frame 19a. The guide member 33 is disposed at a position where the mounting frame 19a is disposed between the guide member 33 and the window foil 20. The guide member 33 is disposed at a position away from the window foil 20 and the mounting frame 19a in the traveling direction of the electron beam e. Therefore, a space Sp1 is present between the window foil 20 and the mounting frame 19a and the guide member 33. The space Sp1 is surrounded by the window foil 20, the mounting frame 19a, the cooling gas discharge device 31, and the guide member 33. The surface 20a of the window foil 20 facing the outside of the scan tube 16 is exposed to the space Sp1 from the opening 19b.

[0021] The guide member 33 is fixed to the cooling gas discharge device 31 by, for example, a bolt (not shown) on the outer periphery of the discharge port 32. The discharge port 32 opens into the space Sp1. Therefore, the cooling gas is discharged from the discharge port 32 into the space Sp1.

[0022] The guide member 33 has an exhaust port 34 through which the electron beam e passes after passing through the opening window portion 19. The opening window portion 19, the window foil 20, the opening 19b, and the exhaust port 34 are arranged in the traveling direction of the electron beam e in the following order: opening window portion 19, window foil 20, opening 19b, and exhaust port 34. The cooling gas supplied to the space Sp1 from the discharge port 32 flows toward the window foil 20 by being guided by the guide member 33. The cooling gas is then exhausted to the outside of the space Sp1 through the exhaust port 34.

[0023] (Configuration of flow path 35) The electron beam irradiation device 10 has a flow path 35 through which a cooling gas for cooling the window foil 20 passes. The flow path 35 includes, for example, a portion of the cooling gas discharge device 31 through which the cooling gas passes. The flow path 35 also includes a space Sp1. The flow path 35 has an outlet 34 since the outlet 34 is included in the guide member 33 surrounding the space Sp1. The cooling gas is discharged from the outlet 34 to the outside of the flow path 35. Furthermore, the surface 20a of the window foil 20 facing the outside of the scan tube 16 is exposed to the space Sp1, and is therefore exposed to the flow path 35. The space Sp1 corresponds to, for example, an end point of the flow path 35.

[0024] (Configuration of shield S) 1 and 2, among the components of the electron beam irradiation device 10, at least the filament 11, the acceleration tube 13, and the scan tube 16 are surrounded by a shield S. For convenience of explanation, the shield S is omitted from FIG. 1. The shield S is for blocking X-rays generated when the electron beam e is irradiated onto the irradiation target 43. The shield S is formed of, for example, a lead-based metal material.

[0025] The shield S includes a first component S1 in which the filament 11, the accelerating tube 13, and the scanning tube 16 are arranged, and a second component S2 that covers the opening Sa of the first component S1. The second component S2 is configured to be detachable from the first component S1. In a state in which the first component S1 and the second component S2 are connected, X-rays generated when the electron beam e emitted from the electron beam irradiation device 10 is irradiated onto the irradiation target 43 are prevented from flowing out of the shield S. The cooling gas discharged from the exhaust port 34 to the outside of the flow path 35 is discharged to the outside of the shield S from an exhaust port (not shown) that the shield S has.

[0026] (Configuration of control device 41) The above-mentioned filament power supply 12, accelerating electrode power supply 15, scanning coil 18, vacuum pump 21, and cooling gas discharge device 31 are controlled by a control device 41. The control device 41 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 adjusts the vacuum of the internal space 17 of the accelerating tube 13 and the scanning tube 16 through the vacuum pump 21. The control device 41 also supplies cooling gas to the window foil 20 through the cooling gas discharge device 31. For example, while the cooling gas is being supplied to the window foil 20, the control device 41 controls the cooling gas discharge device 31 so that the flow rate of the cooling gas discharged from the discharge port 32 into the space Sp1 is constant.

[0027] The control device 41 may be configured as a circuit including one or more processors that execute various processes according to a computer program (software), or one or more dedicated hardware circuits, such as an application specific integrated circuit (ASIC), that execute at least a part of the various processes, or a combination thereof. The processor includes a CPU and memory, such as RAM and ROM, that stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer.

[0028] (Irradiation of the electron beam e to the object to be irradiated 43) As shown in FIG. 1, the electron beam e emitted through the window foil 20 attached to the open window 19 is irradiated onto the irradiated object 43 being transported in the transport direction x by, for example, a transport device 42. Then, a predetermined process is performed on the irradiated object 43 by the electron beam e. The electron beam irradiating device 10 is disposed, for example, such that the longitudinal direction of the approximately rectangular open window 19 faces the transport orthogonal direction y of the transport device 42. A predetermined scan of the electron beam e including the transport direction x and the transport orthogonal direction y is performed, so that the electron beam e is irradiated onto an approximately rectangular irradiation area A corresponding to the open window 19. The irradiation effect of the electron beam e onto the irradiated object 43 can be expected to be, for example, improvement of the properties of the material, addition of functions, sterilization, etc.

[0029] (Configuration of protective cover 50) Next, the protective cover 50 for protecting the window foil 20 will be described. As shown in Fig. 3, the electron beam irradiation device 10 is provided with a protective cover 50 that is detachable from the guide member 33. Fig. 3 shows a part of the electron beam irradiation device 10 in a state in which the protective cover 50 is attached. For example, the protective cover 50 has a shape that is slightly larger than the discharge port 34.

[0030] Here, the outer surface 33a of the guide member 33 constitutes a part of the outer wall surface of the flow path 35. The outer surface 33a is the outer surface of the guide member 33 when the space Sp1 is the inside. The protective cover 50 is detachably attached to the outer surface 33a and covers the entire outlet 34. That is, the protective cover 50 is detachably attached to the outer wall surface of the flow path 35 and covers the entire outlet 34.

[0031] The electron beam irradiation device 10 may have an attachment member 51 for removably attaching the protective cover 50 to the guide member 33. The attachment member 51 is, for example, a bolt. The protective cover 50 is fixed to the guide member 33 by the attachment member 51 in a manner to block the discharge port 34. When the protective cover 50 is in the attached state, the attachment member 51 is located outside the flow path 35. For example, when the protective cover 50 is in the attached state, the attachment member 51 is located outside the space Sp1. Note that the protective cover 50 can be removed from the outer surface 33a of the guide member 33 by removing the attachment member 51.

[0032] When the protective cover 50 is attached to the guide member 33, the protective cover 50 covers the outer side of the window foil 20. More specifically, the protective cover 50 covers the exhaust port 34, thereby covering the surface 20a of the window foil 20 on the outer side of the scan tube 16. The portion of the protective cover 50 exposed from the exhaust port 34 to the space Sp1, i.e., the portion exposed from the exhaust port 34 to the flow path 35, faces the surface 20a of the window foil 20 in the traveling direction of the electron beam e. As a result, the protective cover 50 prevents contact with the window foil 20 from the outer side, thereby preventing damage to the window foil 20 due to contact from the outer side.

[0033] (Configuration of measuring unit 61) The electron beam irradiation device 10 also has a measurement unit 61 that measures the pressure in the flow path 35. For example, an electronic pressure gauge is used as the measurement unit 61. The measurement unit 61 measures the pressure in the flow path 35. The measurement unit 61 also outputs a signal corresponding to the measurement result to the control device 41. For example, the measurement unit 61 outputs an electric signal corresponding to the measured pressure value in the flow path 35. The timing of the measurement of the pressure in the flow path 35 by the measurement unit 61 and the timing of the output of the electric signal by the measurement unit 61 can be set arbitrarily. For example, the measurement unit 61 continuously measures the pressure in the flow path 35. And the measurement unit 61 outputs an electric signal corresponding to the measurement result at that time point, for example, at every preset time.

[0034] (Detection by the control device 41 as to whether the protective cover 50 is attached or not) The control device 41 detects whether the protective cover 50 is in an attached state based on the measurement result of the measurement unit 61. When the cooling gas is supplied to the space Sp1, when the protective cover 50 is removed and then attached, the pressure in the flow path 35 increases. For example, the control device 41 has a threshold value for determining whether the protective cover 50 is in an attached state. The threshold value is, for example, a value according to the pressure in the flow path 35 when the protective cover 50 is in an attached state. The control device 41 compares the measurement result input from the measurement unit 61 with the threshold value. Then, when the measurement result input from the measurement unit 61 is equal to or less than the threshold value, the control device 41 determines that the protective cover 50 is not in an attached state. That is, the control device 41 detects that the protective cover 50 is not in an attached state. On the other hand, when the measurement result input from the measurement unit 61 is greater than the threshold value, the control device 41 determines that the protective cover 50 is in an attached state. That is, the control device 41 detects that the protective cover 50 is in an attached state. The control device 41 permits the output of the electron beam e from the filament 11 on the condition that the protective cover 50 is not attached.

[0035] (Configuration of the notification unit 62) The electron beam irradiation device 10 may also include a notification unit 62 that notifies the operator that the protective cover 50 is in an attached state based on the detection result of the control device 41 regarding the attached state of the protective cover 50. The notification unit 62 is operated, for example, under the control of the control device 41. The notification unit 62 includes at least one of a display, a speaker, and an indicator light, and notifies the operator that the protective cover 50 is in an attached state by displaying on the display, outputting sound from the speaker, or lighting up the indicator light.

[0036] The operation of this embodiment will be described. 3, when the electron beam irradiation device 10 is not in use, the worker removes the second constituent body S2 from the first constituent body S1 to open the opening Sa of the first constituent body S1, and then attaches the protective cover 50 to the outer surface 33a of the guide member 33 with the attachment member 51. As a result, the outer side of the window foil 20 is covered with the protective cover 50. In addition, the exhaust port 34 is covered with the protective cover 50. At this time, the cooling gas is supplied from the discharge port 32 to the space Sp1.

[0037] When the protective cover 50 is attached to the outer surface 33a of the guide member 33, the discharge port 34 is covered, and the pressure in the flow path 35 becomes higher than when the protective cover 50 is not attached to the outer surface 33a of the guide member 33. The measurement result output by the measurement unit 61 also changes according to the pressure in the flow path 35. The control device 41 compares the measurement result input from the measurement unit 61 with a threshold value. Then, when the measurement result input from the measurement unit 61 is greater than the threshold value, the control device 41 determines that the protective cover 50 is in an attached state. That is, the control device 41 detects that the protective cover 50 is in an attached state.

[0038] When the control device 41 detects that the protective cover 50 is attached, it performs control so as not to permit output of the electron beam e from the filament 11. This prevents the electron beam e from being emitted with the protective cover 50 attached.

[0039] Next, an example of the operation of the notification unit 62 will be described. When the control device 41 detects that the protective cover 50 is attached and an output operation of the electron beam e is performed by the worker, the control device 41 displays that the protective cover 50 is attached on a display serving as the notification unit 62. Alternatively, the control device 41 outputs sound from a speaker serving as the notification unit 62. Alternatively, the control device 41 turns on an indicator light serving as the notification unit 62. This notifies the worker that the protective cover 50 is attached.

[0040] When using the electron beam irradiation device 10, as shown in FIG. 2, the operator removes the protective cover 50 from the outer surface 33a of the guide member 33, and then closes the opening Sa of the first structure S1 with the second structure S2. When the cooling gas is supplied from the discharge port 32 to the space Sp1 in this state, the pressure in the flow path 35 becomes lower than when the protective cover 50 is attached to the outer surface 33a of the guide member 33, because the exhaust port 34 is not covered by the protective cover 50. The measurement result output by the measurement unit 61 also changes depending on the pressure in the flow path 35. The control device 41 compares the measurement result input from the measurement unit 61 with a threshold value. Then, when the measurement result input from the measurement unit 61 is equal to or lower than the threshold value, the control device 41 determines that the protective cover 50 is in an unattached state. That is, the control device 41 detects that the protective cover 50 is in an unattached state. When the control device 41 detects that the protective cover 50 is in an unattached state, it permits the output of the electron beam e from the filament 11.

[0041] The effects of this embodiment will be described. (1) The electron beam irradiation device 10 includes a filament 11 that generates an electron beam e, and a scanning tube 16 having an opening window 19 through which the electron beam e passes. The electron beam irradiation device 10 also includes a window foil 20 that is provided to cover the opening window 19 and transmits the electron beam e from inside the scanning tube 16 to the outside of the scanning tube 16, and a removable protective cover 50 that covers the outside side of the window foil 20. The electron beam irradiation device 10 also includes a flow path 35 through which a surface 20a of the window foil 20 on the outside side of the scanning tube 16 is exposed and through which a cooling gas for cooling the window foil 20 passes. The electron beam irradiation device 10 also includes a measurement unit 61 that measures the pressure in the flow path 35. The electron beam irradiation device 10 also includes a control device 41 that detects whether the protective cover 50 is in an attached state based on the measurement result of the measurement unit 61, and allows the emission of the electron beam e through the window foil 20 on the condition that the protective cover 50 is not in an attached state. The flow path 35 has an exhaust port 34 through which the electron beam e passes after passing through the open window portion 19. The cooling gas is exhausted from the exhaust port 34 to the outside of the flow path 35. The protective cover 50 covers the exhaust port 34, and thereby covers the surface 20a of the window foil 20 facing the outside of the scan tube 16.

[0042] According to this configuration, when cooling gas is supplied to the flow path 35, the amount of cooling gas discharged from the outlet 34 to the outside of the flow path 35 is greater when the protective cover 50 is not attached than when the protective cover 50 is attached. Therefore, the pressure in the flow path 35 when the protective cover 50 is attached is higher than the pressure in the flow path 35 when the protective cover 50 is removed. Therefore, it is possible to detect whether or not the protective cover 50 is attached based on the pressure in the flow path 35 measured by the measuring unit 61.

[0043] The control device 41 permits the emission of the electron beam e through the window foil 20 on the condition that the protective cover 50 is not attached. Therefore, if the protective cover 50 is left in a non-attached state, the control device 41 does not permit the emission of the electron beam e. This makes it possible to suppress damage to the protective cover 50 caused by irradiation of the electron beam e to the protective cover 50.

[0044] (2) The electron beam irradiation device 10 includes a notification unit 62 that issues a notification based on the detection result of the control device 41 regarding whether or not the protective cover 50 is attached. With this configuration, the notification unit 62 can issue a notification based on the detection result of the control device 41. This makes it easier for an operator to recognize whether or not emission of the electron beam e is permitted, thereby improving operability.

[0045] (3) The notification unit 62 notifies the operator that the protective cover 50 is in the attached state when the control device 41 detects that the protective cover 50 is in the attached state. According to this configuration, the notification unit 62 can notify the operator that the protective cover 50 is in the attached state.

[0046] (4) The electron beam irradiation device 10 includes an attachment member 51 that attaches the protective cover 50 to the outer surface 33a of the flow path 35. When the protective cover 50 is in the attached state, the attachment member 51 is located outside the flow path 35. With this configuration, the attachment member 51 does not protrude into the inside of the flow path 35. Therefore, it is possible to suppress the attachment member 51 from disturbing the flow of the cooling gas.

[0047] This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction. As shown in FIG. 4, the electron beam irradiation device 10 may include a seal member 71 that seals between the discharge port 34 and the protective cover 50. The protective cover 50 is detachably attached to the outer surface 33a of the guide member 33 to cover the entire discharge port 34. The seal member 71 is located between the outer peripheral portion of the discharge port 34 on the outer surface 33a and the protective cover 50. The seal member 71 surrounds the discharge port 34 and is in close contact with each of the outer peripheral portion of the discharge port 34 on the outer surface 33a and the protective cover 50. The seal member 71 forms, for example, a ring shape that surrounds the discharge port 34 when viewed from the traveling direction of the electron beam e. Note that the term "ring" used in this description may refer to any structure that forms a loop, i.e., a continuous shape without ends, as well as a configuration that forms an overall loop shape having a gap such as a C-shape. The shape of the "ring" includes, but is not limited to, a circle, an ellipse, and a polygon with sharp or rounded corners.

[0048] According to this configuration, when the protective cover 50 is attached to the outer surface 33a of the guide member 33, the seal member 71 prevents the cooling gas from passing between the protective cover 50 and the outer surface 33a. Therefore, the time from when the protective cover 50 is attached to the outer surface 33a until the pressure in the flow path 35 reaches a pressure at which the control device 41 can detect that the protective cover 50 is attached can be made shorter than when the electron beam irradiation device 10 does not include the seal member 71. Therefore, the time from when the protective cover 50 is attached until the control device 41 detects that the protective cover 50 is attached can be made shorter.

[0049] The mounting member 51 may protrude into the flow passage 35 . In the above embodiment, the threshold value is a value according to the pressure in the flow path 35 when the protective cover 50 is in an attached state. However, the threshold value may be, for example, a value based on the increase in pressure in the flow path 35 per unit time after the protective cover 50 is attached. In this case, the control device 41 calculates the increase in pressure in the flow path 35 per unit time based on the measurement result input from the measurement unit 61. Then, the control device 41 compares the calculation result with the threshold value, and when the calculation result is greater than the threshold value, the control device 41 determines that the protective cover 50 is in an attached state. That is, the control device 41 detects that the protective cover 50 is in an attached state. On the other hand, the control device 41 compares the calculation result with the threshold value, and when the calculation result is equal to or less than the threshold value, the control device 41 determines that the protective cover 50 is in an unattached state. That is, the control device 41 detects that the protective cover 50 is in an unattached state.

[0050] In the above embodiment, the measurement unit 61 measures the pressure in the flow path 35. However, the measurement unit 61 may measure the flow rate of the cooling gas passing through the flow path 35. Even in this case, the control device 41 detects whether the protective cover 50 is in an attached state based on the measurement result of the measurement unit 61. In this case, the threshold value for determining whether the protective cover 50 is in an attached state is, for example, a value corresponding to the flow rate of the cooling gas passing through the flow path 35 when the protective cover 50 is in an attached state. The control device 41 compares the measurement result input from the measurement unit 61 with the threshold value. Then, when the measurement result input from the measurement unit 61 is equal to or greater than the threshold value, the control device 41 determines that the protective cover 50 is not in an attached state. That is, the control device 41 detects that the protective cover 50 is not in an attached state. On the other hand, when the measurement result input from the measurement unit 61 is smaller than the threshold value, the control device 41 determines that the protective cover 50 is in an attached state. That is, the control device 41 detects that the protective cover 50 is in an attached state.

[0051] According to this configuration, when cooling gas is supplied to the flow path 35, the amount of cooling gas discharged from the outlet 34 to the outside of the flow path 35 is greater when the protective cover 50 is not attached than when the protective cover 50 is attached. Therefore, the flow rate of cooling gas passing through the flow path 35 when the protective cover 50 is attached is less than the flow rate of cooling gas passing through the flow path 35 when the protective cover 50 is not attached. Therefore, it is possible to detect whether or not the protective cover 50 is attached based on the flow rate of cooling gas passing through the flow path 35 measured by the measuring unit 61.

[0052] When the protective cover 50 is in the attached state, it is not necessary for it to cover the entire exhaust port 34. However, when the protective cover 50 is in the attached state, it covers the exhaust port 34 to an extent that the window foil 20 can be protected.

[0053] The material used for the window foil 20 is not limited to the materials in the above embodiment, and materials other than titanium-based metallic materials may be used. The material used for the shielding body S is not limited to the materials in the above embodiment, and materials other than lead-based metallic materials such as concrete may be used.

[0054] The notification unit 62 in the above embodiment notifies the user that the protective cover 50 is in an attached state when the control device 41 detects that the protective cover 50 is in an attached state. However, the notification unit 62 is not limited to this, and may be any unit that issues a notification based on the detection result of the control device 41 regarding whether the protective cover 50 is in an attached state. For example, the notification unit 62 may be configured to notify the user that the protective cover 50 is in an unattached state (i.e., that emission of the electron beam e is permitted) when the control device 41 detects that the protective cover 50 is in an unattached state.

[0055] In the electron beam irradiation device 10 of the above embodiment, the opening direction of the opening window portion 19 is set to face downward, i.e., the traveling direction of the electron beam e is set to face downward, but it may be set to face upward, horizontally, or obliquely.

[0056] In the above embodiment, the electron beam irradiation device 10 is a scanning type electron beam irradiation device that forms an electron beam e from electrons emitted from a single filament 11, scans the electron beam e with the scanning coil 18, and irradiates the irradiation area A. However, the electron beam irradiation device 10 may be an area type electron beam irradiation device that uses a plurality of filaments 11 corresponding to the irradiation area A and omits the scanning coil 18.

[0057] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the meaning and scope of the claims.

[0058] The technical ideas that can be understood from the above-described embodiment and modified examples will be described. (i) In the electron beam irradiation device, the notification unit notifies the user that the protective cover is in an attached state when the control unit detects that the protective cover is in an attached state.

[0059] According to this configuration, the notification section can notify the operator that the protective cover is in an attached state. (b) In the electron beam irradiation device, the protective cover is removably attached to an outer wall surface of the flow path to cover the entire outlet, and a sealing member is provided between an outer circumferential portion of the outlet on the outer wall surface of the flow path and the protective cover, the sealing member surrounding the outlet and being in close contact with each of the outer circumferential portion and the protective cover.

[0060] According to this configuration, when the protective cover is attached to the outer wall surface of the flow path, the sealing member prevents the cooling gas from passing between the protective cover and the outer wall surface. Therefore, when the measurement unit measures the pressure in the flow path, the time from when the protective cover is attached to the outer wall surface of the flow path until the pressure in the flow path reaches a pressure at which the control unit can detect that the protective cover is attached can be shorter than when the electron beam irradiation device does not include a sealing member. Also, when the measurement unit measures the flow rate of the cooling gas passing through the flow path, the time from when the protective cover is attached to the outer wall surface of the flow path until the flow rate of the cooling gas passing through the flow path reaches a flow rate at which the control unit can detect that the protective cover is attached can be shorter than when the electron beam irradiation device does not include a sealing member. Therefore, the time required for the control unit to detect that the protective cover is attached can be shortened after the protective cover is attached.

[0061] (c) The electron beam irradiation device includes a mounting member for mounting the protective cover to an outer wall surface of the flow path, and when the protective cover is in an attached state, the mounting member is located outside the flow path.

[0062] According to this configuration, the attachment member does not protrude into the flow passage, and therefore, the flow of the cooling gas can be prevented from being disturbed by the attachment member. [Explanation of symbols]

[0063] 10...Electron beam irradiation device 11...Filament (electron beam generating part) 16...Scanning tube (housing part) 19…Opening window 20…Window foil 20a…side 22...Control device (control unit) 34…Discharge port 35...Flow path 50…Protective cover 61...Measuring part 62…Information Department e…electron beam

Claims

1. an electron beam generating unit that generates an electron beam; a housing having an opening window through which the electron beam passes; a window foil provided to cover the opening window portion and allowing the electron beam to pass from the inside of the housing portion to the outside of the housing portion; A removable protective cover that covers the outer side of the window foil; An electron beam irradiation apparatus comprising: a flow path through which a cooling gas for cooling the window foil passes, the flow path exposing a surface of the window foil facing the exterior of the housing; a measuring unit for measuring a pressure in the flow passage or a flow rate of the cooling gas passing through the flow passage; a control unit that detects whether the protective cover is in an attached state based on a measurement result of the measurement unit, and allows the emission of the electron beam through the window foil on the condition that the protective cover is not in an attached state, the flow path has an outlet through which the electron beam passes after passing through the opening window, The cooling gas is discharged from the outlet to the outside of the flow path. The protective cover covers the exhaust port, thereby covering the outer surface of the window foil of the housing portion.

2. 2. The electron beam irradiation device according to claim 1, further comprising a notification unit that issues a notification based on a detection result of said control unit as to whether said protective cover is in an attached state.

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