Electron beam irradiation apparatus, protective cover for electron beam irradiated object, and method for protecting electron beam irradiated object

Abstract

To provide an electron beam irradiation device capable of protecting an object irradiated with electron beams, a protection cover for protecting an irradiated object in the electron beam irradiation device, and a method for protecting an irradiated object in the electron beam irradiation device.SOLUTION: An electron beam irradiation device 1 includes: an irradiation chamber 4; a device body 3 applying electron beams to an irradiated object 2 within the irradiation chamber 4 from an irradiation window unit 30; and a protection cover 6 protecting the irradiated object 2. The protection cover 6 includes: a coating material 7 that can transmit electron beams and covers the irradiated object 2; and a fixture 8 placed on the coating material 7 so as to be along an outer circumferential edge of the coating material 7. In the coating material 7, a part for placing the fixture 8 is pressed against a placement table 5 by the fixture 8, and the fixture 8 includes an inner flow path 80 in which cooling fluid is circulated, an inlet 81 introducing the cooling fluid to the inner flow path 80, and an outlet 82 deriving the cooling fluid from the inner flow path 80.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an electron beam irradiation device, a protective cover for an electron beam irradiated object, and a method for protecting an electron beam irradiated object.

Background Art

[0002] Generally, as shown in FIG. 6, an electron beam irradiation device includes a device main body 111 that generates an electron beam, and an irradiation chamber 112 in which the device main body 111 is provided. The device main body 111 generates electrons by heating a filament in a vacuum, accelerates the electrons to form an electron beam, and emits the electron beam from an irradiation window portion 113, thereby irradiating an electron beam irradiated object (also referred to as an "irradiated object" in the present disclosure) 110 disposed opposite to the irradiation window portion 113 in the irradiation chamber 112. The irradiation window portion 113 is covered with a metal foil (window foil) 114 through which the electron beam can pass, and this metal foil 114 functions as a boundary between the inside of the device main body 111 in a vacuum state and the inside of the irradiation chamber 112 in an atmospheric pressure state.

[0003] Since the metal foil 114 of the irradiation window portion 113 is exposed to the electron beam, its temperature rises by absorbing a part of the energy of the electron beam. The metal foil 114 is formed of, for example, titanium or the like. However, if it generates excessive heat due to electron beam irradiation, it may deform due to a decrease in strength or break due to deterioration. Therefore, an electron beam irradiation device provided with a cooler 115 for blowing a cooling gas such as air or nitrogen gas onto the metal foil 114 of the irradiation window portion 113 to cool the metal foil has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The cooling gas blown onto the metal foil 114 of the irradiation window 113 may reflect off the metal foil 114 and forcefully strike the object to be irradiated 110 positioned opposite the irradiation window 113. The object to be irradiated 110 may move due to the impact of the cooling gas. Furthermore, if the object to be irradiated 110 is a lightweight material such as powder or granules, the object to be irradiated 110 may be scattered. In addition, the scattered object to be irradiated 110 may strike the metal foil 114 of the irradiation window 113, potentially damaging the metal foil 114. Moreover, the convection of the cooling gas reflected by the metal foil 114 may cause dust inside the irradiation chamber 112 to adhere to the object to be irradiated 110. Note that if the object to be irradiated 110 is a powder or granule, it is usually placed inside the irradiation chamber 112 in a bag. In this case, the thermal expansion of the air contained in the powder due to electron beam irradiation may cause individual particles or powder to puncture the bag, potentially scattering the irradiated material 110.

[0006] The present invention has been made in view of the above circumstances and aims to provide an electron beam irradiation apparatus capable of protecting an object to be irradiated by an electron beam, a protective cover for protecting an object to be irradiated in an electron beam irradiation apparatus, and a method for protecting an object to be irradiated in an electron beam irradiation apparatus. [Means for solving the problem]

[0007] A first aspect of the present invention relates to an electron beam irradiation apparatus comprising at least an irradiation chamber equipped with a mounting table on which an object to be irradiated by an electron beam is placed, and a main body of an apparatus that generates an electron beam and irradiates the object to be irradiated by an electron beam from an irradiation window into the irradiation chamber. The electron beam irradiation apparatus of the present invention further comprises a protective cover provided on the mounting table to protect the object to be irradiated by an electron beam, the protective cover comprising a covering material that is permeable to the electron beam and covers the object to be irradiated by an electron beam, and at least one fixing device placed on the covering material so as to be along at least a portion of the outer edge of the covering material, wherein the portion of the covering material on which the fixing device is placed is pressed against the mounting table by the fixing device, and the fixing device has an internal passage through which a cooling fluid for cooling the fixing device flows, an inlet for introducing the cooling fluid into the internal passage, and an outlet for discharging the cooling fluid from the internal passage.

[0008] A second aspect of the present invention relates to a protective cover provided on the aforementioned mounting base for protecting an object to be irradiated by an electron beam, in an electron beam irradiation apparatus for irradiating an object to be irradiated by an electron beam placed on a mounting base. The protective cover of the present invention comprises a covering material that is permeable to the electron beam and covers the object to be irradiated by an electron beam, and at least one fixing device that is placed on the covering material so as to be along at least a portion of the outer edge of the covering material and presses the covering material toward the aforementioned mounting base, wherein the fixing device has an internal flow path through which a cooling fluid for cooling the fixing device flows, an inlet for introducing the cooling fluid into the internal flow path, and an outlet for discharging the cooling fluid from the internal flow path.

[0009] A third aspect of the present invention relates to an electron beam irradiation apparatus for irradiating an object to be irradiated with an electron beam placed on a mounting table, and to a method for protecting the object to be irradiated with an electron beam provided on the mounting table. The method for protecting an object to be irradiated with an electron beam is characterized by covering the object to be irradiated with an electron beam-permeable covering material, placing at least one fixing device on the covering material so as to follow at least a portion of the outer edge of the covering material and pressing the covering material toward the mounting table, and circulating a cooling fluid inside the fixing device to cool the fixing device. [Effects of the Invention]

[0010] According to the present invention, [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram of the electron beam irradiation apparatus. [Figure 2] This is a schematic diagram showing an enlarged view of the main parts of Figure 1. [Figure 3] Figure 1 is a plan view of the protective cover. [Figure 4] This is a plan view of a modified protective cover. [Figure 5] This is a plan view of a modified protective cover. [Figure 6] This is a schematic diagram of a conventional electron beam irradiation device. [Modes for carrying out the invention]

[0012] Hereinafter, an electron beam irradiation apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. Figures 1 to 3 show a schematic configuration of the electron beam irradiation apparatus 1 of this embodiment. The electron beam irradiation apparatus 1 irradiates an object to be irradiated 2 with an electron beam to perform, for example, material property improvement, functional addition, sterilization, etc. on the object to be irradiated 2. The electron beam irradiation apparatus 1 comprises at least a main body 3 that generates an electron beam to irradiate the object to be irradiated 2, an irradiation chamber 4 equipped with a mounting table 5 on which the object to be irradiated 2 is placed, and a protective cover 6 provided on the mounting table 5 in the irradiation chamber 4 to protect the object to be irradiated 2.

[0013] The object to be irradiated by the electron beam 2 is not particularly limited, and examples include electric wires, optical cables, wires, rubber hoses, tubes, films, sheets, powders, and granular materials.

[0014] The main body of the device 3 generates an electron beam and irradiates the object to be irradiated 2 with the electron beam. The main body of the device 3 generates electrons by heating a filament while the internal pressure is reduced by a vacuum pump, accelerates the electrons into an electron beam, and emits the electron beam to the outside of the main body of the device 3 through the irradiation window 30. The structure of the main body of the device 3 is not particularly limited as long as it is capable of generating an electron beam and irradiating the object to be irradiated 2 as described above, and it may be a scanning type or a non-scanning type.

[0015] The irradiation window 30 is a part of the apparatus body 3 that opens within the irradiation chamber 4, and the area below the irradiation window 30 is the electron beam irradiation area. The irradiation window 30 is covered with a metal foil (window foil) 31. The metal foil 31 is a thin sheet of metal that allows electron beams to pass through in its thickness direction, and can be made of titanium, for example. The thickness of the metal foil 31 is preferably as thin as possible to minimize energy loss of electron beams passing through it, but since the metal foil 31 is the boundary between the vacuum state inside the apparatus body 3 and the atmospheric pressure state inside the irradiation chamber 4 and functions as a pressure boundaryr, the thickness of the metal foil 31 is designed to withstand a differential pressure of 1 atmosphere.

[0016] The electron beam irradiation apparatus 1 is not particularly limited, but preferably further comprises a cooler 10 for cooling the irradiation window 30 with a cooling gas. The cooler 10 comprises a nozzle 100 for blowing cooling gas onto the metal foil 31 of the irradiation window 30, and a duct 101 for circulating the cooling gas supplied from a cooling gas supply source (not shown) to the nozzle 100.

[0017] Since the metal foil 31 of the irradiation window portion 30 is exposed to the electron beam, its temperature rises by absorbing part of the energy of the electron beam. If it generates excessive heat due to electron beam irradiation, it may deform due to a decrease in strength or be damaged due to deterioration. Therefore, a cooler 10 is provided in the apparatus main body 3 to blow a cooling gas such as air or nitrogen gas onto the metal foil 31 of the irradiation window portion 30 to cool the metal foil 31.

[0018] The irradiation chamber 4 is formed of a lead-based metal to block the outflow of the electron beam to the outside. The irradiation chamber 4 is, for example, a rectangular parallelepiped box, and a mounting table 5 is provided on the inner bottom wall 40 thereof. Further, the irradiation chamber 4 is provided with an apparatus main body 2 above the mounting table 5 so that the irradiation window portion 30 and the mounting table 5 are opposed to each other.

[0019] The mounting table 5 includes a top plate portion 50 and one or a plurality of leg portions 51, and the irradiated object 2 can be placed on the upper surface of the top plate portion 50. The upper surface of the top plate portion 50 is flat. The top plate portion 50 is not particularly limited, but for example, cooling means for cooling the top plate portion 50 by introducing and discharging cooling water into the top plate portion 50 is preferably provided. The mounting table 5 is not particularly limited, but is preferably installed movably on the bottom wall 40 of the irradiation chamber 4.

[0020] The protective cover 6 is provided on the mounting table 5 in the irradiation chamber 4 so as to cover the irradiated object 2. The protective cover 6 includes a covering material 7 that covers the irradiated object 2 and at least one fixture 8 that is placed on the covering material 7 along at least a part of the outer peripheral edge of the covering material 7.

[0021] The covering material 7 protects the irradiated object 2 from the cooling gas that is reflected by the metal foil 31 when the cooling gas is blown onto the metal foil 31 of the irradiation window portion 30 and contacts the irradiated object 2. Further, the covering material 7 protects the irradiated object 2 from foreign matters such as dust in the irradiation chamber 4 adhering thereto. Further, the covering material 7 protects the irradiated object 2 from scattering from the mounting table 5 due to the blowing of the above-described cooling gas or other factors.

[0022] The covering material 7 is permeable to electron beams in its thickness direction. Therefore, even if the object to be irradiated 2 on the mounting table 5 is covered by the covering material 7, the object to be irradiated 2 can still be irradiated with electron beams. Furthermore, the covering material 7 generates heat when irradiated with electron beams, and therefore has heat resistance. In addition, the covering material 7 is durable enough to withstand being hit by cooling gas reflected by the metal foil 31 of the irradiation window 30 with force, without being damaged. Furthermore, the covering material 7 is not particularly limited, but preferably has flexibility. Because the covering material 7 is flexible and can be easily deformed, even if the height of the object to be irradiated 2 on the mounting table 5 changes, the height of the covering material 7 (the vertical distance H from the top surface of the mounting table 5 to the uppermost position of the covering material 7 as shown in Figure 2) can be easily changed according to the height of the object to be irradiated 2. Furthermore, the coating material 7 is not particularly limited, but preferably has sufficient durability to withstand impacts from the irradiated object 2 without being damaged, because, for example, when the irradiated object 2 is a powder or granular material, individual particles or powder from the irradiated object 2 may scatter from the mounting base 5 and collide with the coating material 7. Also, the coating material 7 is not particularly limited, but preferably is made of an inexpensive material.

[0023] From the above-mentioned viewpoint, the covering material 7 can be made of an aluminum sheet, for example, a thin aluminum foil. However, the covering material 7 can also be made of a metal sheet made of a material other than aluminum, for example, a titanium sheet, preferably a thin titanium foil, and it may even be made of a sheet (or film) formed of a material other than metal, although its heat resistance is inferior, and the material is not particularly limited. Furthermore, the covering material 7 does not necessarily have to be in the form of a flexible sheet, and may be in the form of a hard plate that does not easily deform, and its form is not particularly limited.

[0024] Since the coating material 7 is exposed to electron beams, its temperature rises as it absorbs some of the electron beam's energy. The thickness of the coating material 7 is preferably as thin as possible to minimize energy loss of electron beams passing through it and to suppress the temperature rise of the coating material 7 due to electron beam irradiation. The thickness of the coating material 7 is set appropriately depending on the material, but if the coating material 7 is made of aluminum, it is preferably 11 μm to 17 μm. Aluminum foil can be used as the aluminum coating material 7 with a thickness of 11 μm to 17 μm, and since aluminum foil is generally readily available and inexpensive, costs can be reduced.

[0025] The covering material 7 is held in place by the fixing device 8, which is placed along at least a portion of its outer edge, so that the portion on which the fixing device 8 is placed is pressed down onto the mounting base 5 by the fixing device 8. As a result, the covering material 7 is held in place in a specific location on the mounting base 5, specifically in a location that covers the object to be irradiated 2.

[0026] The mounting device 8 is not particularly limited, but is preferably made of a rust-resistant metal such as stainless steel. The plan view shape of the mounting device 8 is not particularly limited, as long as it can press a portion of the covering material 7 onto the mounting base 5 from above around the object to be irradiated 2.

[0027] However, from the viewpoint of stably positioning the covering material 7 on the mounting base 5 using the fixing device 8, and making the space for accommodating the object to be irradiated 2 between the covering material 7 and the mounting base 5 as enclosed as possible, the fixing device 8 preferably has a frame shape in plan view, placed on the covering material 7 so as to follow the entire circumference of the outer edge of the covering material 7 and positioned around the object to be irradiated 2. The shape of the fixing device 8 in plan view may be a circular frame shape, an elliptical frame shape, a rectangular frame shape, or any other polygonal frame shape, as long as it surrounds the object to be irradiated 2 and positions the object to be irradiated 2 in the open area inside it.

[0028] The size of the mounting device 8 in plan view is not particularly limited, but preferably it is smaller than the size of the irradiation area of ​​the electron beam irradiated onto the mounting base 5 from the irradiation window 30 of the main body of the device 3 in plan view. In other words, the mounting device 8 is sized to fit inside the irradiation area of ​​the electron beam irradiated onto the mounting base 5 from the irradiation window 30 of the main body of the device 3 in plan view. If the size of the mounting device 8 in plan view is larger than the size of the irradiation area of ​​the electron beam irradiated onto the mounting base 5 in plan view, exposure of the mounting device 8 to the electron beam can be suppressed, and the heating of the mounting device 8 due to electron beam irradiation can be suppressed, but the mounting device 8 may become too large, making it inefficient to manufacture and transport the protective cover 6. If the size of the mounting device 8 in plan view is smaller than the size of the irradiation area of ​​the electron beam irradiated onto the mounting base 5 in plan view, the protective cover 6 can be manufactured and transported efficiently.

[0029] Furthermore, if the size of the mounting device 8 in plan view is smaller than the size of the irradiation area of ​​the electron beam that irradiates the mounting base 5 in plan view, the mounting device 8 will be exposed to the electron beam and will generate heat due to the electron beam irradiation. However, this problem can be solved by circulating a cooling fluid inside the mounting device 8, as will be explained below.

[0030] The shape (outer shape) of the mounting device 8 in a cross-section parallel to the vertical direction can be various shapes such as circular, rectangular, or other polygonal shapes, but it is preferable to make it rectangular, for example, so that the lower surface of the mounting device 8 facing the covering material 7 can be made flat. Because the lower surface of the mounting device 8 is flat, a portion of the covering material 7 can be pressed against the mounting base 5 over a wide area, and the covering material 7 can be stably mounted on the mounting base 5. Furthermore, as will be described later, the covering material 7 is fixed to the mounting device 8 by fixing means 9 such as double-sided tape, and because the part of the mounting device 8 that faces the covering material 7 and is fixed to the covering material 7 has a flat lower surface, the mounting device 8 can be strongly fixed to the covering material 7.

[0031] Regarding the height of the mounting device 8 (the vertical distance h between the lowest position (bottom surface in this embodiment) and the highest position (top surface in this embodiment) when the mounting device 8 is placed on the mounting base 5 shown in Figure 2), if the height of the mounting device 8 is too high, the electron beam irradiated onto the inner surface of the mounting device 8 will be reflected and irradiated onto the object to be irradiated 2, resulting in a higher amount of electron beam irradiation onto the object to be irradiated 2 than intended. Therefore, although the height of the mounting device 8 is not particularly limited, it is preferably 3 cm or less.

[0032] The stationary device 8 is hollow and pipe-shaped, and has an internal passage 80 through which a cooling fluid flows. The stationary device 8 also has an inlet 81 connected to one end of the internal passage 80 for introducing the cooling fluid into the internal passage 80, and an outlet 81 connected to the other end of the internal passage 80 for discharging the cooling fluid from the internal passage 80. The inlet 81 and outlet 81 are connected to a fluid tank (not shown) installed outside the irradiation chamber 4, and a pump (not shown) drives the cooling fluid stored in the fluid tank to circulate, cooling the stationary device 8 through heat exchange as the cooling fluid passes through the inside of the stationary device 8. The cooling fluid is not particularly limited as long as it can cool the stationary device 8, but it is preferably a liquid, and more preferably cooling water such as tap water.

[0033] The mounting device 8 is not particularly limited, but preferably the covering material 7 is fixed by fixing means 9. By fixing the covering material 7 to the mounting device 8 by fixing means 9, the protective cover 6 can be easily carried, and the protective cover 6 can be easily placed on the mounting base 5 so as to cover the covering material 2.

[0034] The fixing means 9 is not particularly limited, but is preferably provided on the portion of the mounting device 8 facing the covering material 7, and in this embodiment, on the lower surface facing the covering material 7. By providing the fixing means 9 on the portion of the mounting device 8 facing the covering material 7, the fixing means 9 is covered by the mounting device 8 and is hidden beneath the mounting device 8 in a plan view, so as not to be exposed. As a result, the fixing means 9 is less likely to be irradiated by electron beams because the electron beams are blocked by the mounting device 8, and it is possible to suppress damage or deterioration or degradation of quality of the fixing means 9 due to the effects of electron beam irradiation.

[0035] The fixing means 9 is not particularly limited as long as it can fix the covering material 7 to the fixture 8, but by using double-sided tape, adhesive, or a tack as the fixing means 9, the covering material 7 can be easily fixed to the fixture 8 and the covering material 7 can be easily removed from the fixture 8. As other fixing means 9, welding or clips that clamp the outer edge of the covering material 7 may be integrally provided on the fixture 8.

[0036] The fixing device 8 may have the covering material 7 fixed by the fixing means 9 along its entire length, or it may have the covering material 7 fixed by the fixing means 9 in only a portion of its entire length. In this embodiment, the fixing device 8, which has a frame shape in plan view, has the covering material 7 fixed by the fixing means 9 along its entire length (entire circumference).

[0037] In the electron beam irradiation apparatus 1 of this embodiment described above, when irradiating an object to be irradiated 2 placed on a mounting table 5 with an electron beam, a protective cover 6 is provided on the mounting table 5 to protect the object to be irradiated. Specifically, the protection method involves irradiating the object to be irradiated 2 with an electron beam while covering it with an electron beam-permeable covering material 7, placing at least one fixing device 8 on the covering material 7 so as to follow at least a portion of the outer edge of the covering material 7, and pressing the covering material 7 toward the mounting table 5 to fix the covering material 7 in place on the mounting table 5, and cooling fluid is circulated inside the fixing device 7 to cool the fixing device 8 during electron beam irradiation.

[0038] In the electron beam irradiation apparatus 1 of this embodiment, the object to be irradiated 2 on the mounting table 5 is covered with a covering material 7 while the object to be irradiated 2 is irradiated with an electron beam. Therefore, even if the cooling gas blown onto the metal foil 31 of the irradiation window 30 by the cooler 10 is reflected by the metal foil 31 and flows towards the object to be irradiated 2 on the mounting table 5, the cooling gas is blocked by the covering material 7 and is prevented from hitting the object to be irradiated 2 with force. Thus, there is no risk of the object to be irradiated 2 moving on the mounting table 5 due to contact with the cooling gas, or of the object to be irradiated 2 being scattered from the mounting table 5 if the object to be irradiated 2 is a lightweight material such as powder or granules. As a result, the object to be irradiated 2 can be irradiated with an electron beam under the desired irradiation conditions. Furthermore, there is no risk of the metal foil 31 being damaged by the scattered object to be irradiated 2 hitting the metal foil 31 of the irradiation window 30. Furthermore, even if dust and other foreign matter in the irradiation chamber 4 are scattered by the convection of the cooling gas reflected by the metal foil 31, there is no risk of the foreign matter adhering to the irradiated object 2.

[0039] When the object to be irradiated 2 is a powder or granular material, it is usually placed on the mounting platform 5 while contained in a bag. In this case, there is a risk that the individual particles or powder may break through the bag due to the thermal expansion of the air contained in the powder or granular material caused by electron beam irradiation, causing the object to be irradiated 2 to scatter. However, the covering material 7 of the protective cover 6 prevents the object to be irradiated 2 from scattering, so the object to be irradiated 2 will only scatter within a predetermined range on the mounting platform 5. Therefore, even in this case, there is no risk of the object to be irradiated 2 scattering and hitting the metal foil 31 of the irradiation window 30, thereby damaging the metal foil 31.

[0040] In addition, in the electron beam irradiation apparatus 1 of this embodiment, the mounting fixture 8 of the protective cover 6 is cooled by a cooling fluid during electron beam irradiation. Since the mounting fixture 8 is exposed to the electron beam, its temperature rises as it absorbs some of the electron beam's energy. If it generates excessive heat due to electron beam irradiation, it may deform due to a decrease in strength or break due to deterioration. By continuously cooling the mounting fixture 8 with a cooling fluid during electron beam irradiation, deformation and breakage can be suppressed, and repeated use is possible.

[0041] In addition, in the electron beam irradiation apparatus 1 of this embodiment, the mounting fixture 8 and the covering material 7 are fixed together by fixing means 9. Therefore, the protective cover 6 is easy to carry. Moreover, the mounting fixture 8 has fixing means 9 on the part facing the covering material 7 (the lower surface in this embodiment). Therefore, exposure of the fixing means 9 to the electron beam can be suppressed, and damage or deterioration of the fixing means 9 due to electron beam irradiation can be suppressed. Furthermore, since the fixing means 9 is also cooled by the cooling fluid circulating inside the mounting fixture 8, damage or deterioration of the fixing means 9 due to cooling can also be suppressed.

[0042] In addition, in the electron beam irradiation apparatus 1 of this embodiment, the mounting device 8 has a flat lower surface facing the covering material 7. Therefore, the mounting device 8 can press a portion of the covering material 7 against the mounting base 5 over a wide area, allowing the covering material 7 to be stably positioned on the mounting base 5. Furthermore, when double-sided tape, adhesive, or a bonding agent is used for the fixing means 9, the mounting device 8 can be strongly fixed to the covering material 7 by providing the fixing means 9 on the flat lower surface of the mounting device 8.

[0043] In addition, in the electron beam irradiation apparatus 1 of this embodiment, the fixing device 8 has a frame-like shape in plan view that is placed on the covering material 7 so as to follow the entire circumference of the outer edge of the covering material 7. Therefore, the fixing device 8 allows the covering material 7 to be stably fixed on the mounting base 5, and the space for irradiated object 2 between the covering material 7 and the mounting base 5 can be made as enclosed as possible.

[0044] In addition, in the electron beam irradiation device 1 of this embodiment, the size of the mounting device 8 in a plan view is smaller than the size of the irradiation area of ​​the electron beam irradiated from the irradiation window 30 of the device body 3 onto the mounting base 5 in a plan view. Therefore, the protective cover 6 can be efficiently manufactured and transported.

[0045] In addition, in the electron beam irradiation device 1 of this embodiment, the height of the mounting device is 3 cm or less. Therefore, it is possible to suppress the reflection of electron beams irradiated onto the inner surface of the mounting device 8 and irradiating the object to be irradiated 2, thereby preventing the amount of electron beam irradiation irradiated onto the object to be irradiated 2 from being greater than the intended amount.

[0046] In addition, in the electron beam irradiation apparatus 1 of this embodiment, the covering material 7 is flexible. Therefore, by covering the object to be irradiated 2 with the covering material 7 loosely positioned upwards, the height of the covering material 7 can be easily changed according to the height of the object to be irradiated 2, and covering materials 2 of various heights can be used.

[0047] In addition, in the electron beam irradiation apparatus 1 of this embodiment, the coating material 7 is made of aluminum foil. Therefore, the coating material 7 can be given heat resistance, durability, and flexibility, and because it is thin, the energy loss of the electron beam when passing through the coating material 7 can be suppressed.

[0048] While embodiments of the electron beam irradiation apparatus, protective cover, and method for protecting an irradiated object of the present invention have been described above, the electron beam irradiation apparatus, protective cover, and method for protecting an irradiated object of the present invention are not limited to the embodiments described above, and various modifications are possible without departing from the spirit of this disclosure.

[0049] For example, in the embodiment described above, the fixing device 8 has a frame-like shape in plan view that is placed on the covering material 7 so as to follow the entire circumference of the outer edge of the covering material 7. However, the fixing device 8 does not necessarily have to be shaped so as to follow the entire circumference of the outer edge of the covering material 7. The fixing device 8 may be shaped so as to follow a portion of the outer edge of the covering material 7. For example, as shown in Figure 4, it may be shaped so as to follow three of the four outer edges of the covering material 7 (forming a U-shape in plan view), or, although not shown in the figure, it may be shaped so as to follow two orthogonal sides of the four outer edges of the covering material 7 (forming an L-shape in plan view).

[0050] For example, in the embodiment described above, the covering material 7 is fixed on the mounting base 5 by one fixing device 8, but the fixing device 8 does not necessarily have to be just one; there may be multiple. For example, as shown in Figure 5, there may be two fixing devices 8. In Figure 5, the two fixing devices 8 each have a shape that extends in a straight line when viewed from above. Each fixing device 8 is placed on the covering material 7 along one of the outer edges (four sides) of the covering material 7. In Figure 5, the two fixing devices 8 are placed on the covering material 7 along two sides of the outer edge (four sides) that are parallel to each other, but they may also be placed on the covering material 7 along two sides of the outer edge (four sides) that are perpendicular to each other. In Figure 5, three fixing devices 8, which are linearly shaped in plan view, may be prepared and each placed on the covering material 7 along one of the four outer edges (a total of three edges) of the covering material 7. Alternatively, four fixing devices 8, which are linearly shaped in plan view, may be prepared and each placed on the covering material 7 along one of the four outer edges (a total of four edges). Alternatively, two fixing devices 8, which are L-shaped in plan view, may be prepared and each placed on the covering material 7 along two mutually perpendicular sides (a total of four edges) of the outer edge (a total of four edges) of the covering material 7.

[0051] For example, in the embodiment described above, the fixing device 8 and the covering material 7 are fixed by the fixing means 9, but the fixing device 8 and the covering material 7 do not necessarily need to be fixed by the fixing means 9; the fixing device 8 may simply be placed on the covering material 7.

[0052] As described above, the electron beam irradiation apparatus of the present invention includes the electron beam irradiation apparatus described in Section 1 below in order to solve the problems of this disclosure.

[0053] Item 1. An electron beam irradiation apparatus comprising at least an irradiation chamber equipped with a platform for placing an object to be irradiated by an electron beam, and a main body of an apparatus that generates an electron beam and irradiates the object to be irradiated by an electron beam from an irradiation window into the irradiation chamber, The mounting platform further includes a protective cover provided on the aforementioned mounting platform to protect the object to be irradiated by the electron beam, The protective cover comprises a covering material that is permeable to the electron beam and covers the object irradiated by the electron beam, and at least one fixing device that is placed on the covering material so as to be along at least a portion of the outer edge of the covering material. In the covering material, the portion on which the fixing device is placed is pressed against the aforementioned base by the fixing device. The aforementioned stationary device has an internal passage through which a cooling fluid for cooling the stationary device flows, an inlet for introducing the cooling fluid into the internal passage, and an outlet for discharging the cooling fluid from the internal passage, wherein the device is an electron beam irradiation apparatus.

[0054] Furthermore, the electron beam irradiation apparatus of the present invention includes, as a preferred embodiment of the electron beam irradiation apparatus described in item 1 above, the electron beam irradiation apparatus described in item 2 below.

[0055] Item 2. The electron beam irradiation apparatus according to Item 1, wherein the fixing device is provided with fixing means for fixing the covering material to the fixing device in a portion facing the covering material.

[0056] Furthermore, the present invention includes, as a preferred embodiment of the electron beam irradiation apparatus described in item 2 above, the electron beam irradiation apparatus described in item 3 below.

[0057] Item 3. The fixing device has a flat lower surface facing the covering material. The electron beam irradiation device according to item 2, wherein the fixing means is provided on the lower surface of the fixing device.

[0058] Furthermore, the present invention includes, as a preferred embodiment of the electron beam irradiation apparatus described in paragraphs 2 and 3 above, the electron beam irradiation apparatus described in paragraph 4 below.

[0059] Item 4. The electron beam irradiation apparatus according to item 2 or 3, wherein the fixing means is an adhesive, a tack, or double-sided tape.

[0060] Furthermore, the present invention includes, as a preferred embodiment of the electron beam irradiation apparatus described in items 1 to 4 above, the electron beam irradiation apparatus described in item 5 below.

[0061] Item 5. The electron beam irradiation apparatus according to any one of items 1 to 4, wherein the fixing device has a frame-like shape in plan view and is placed on the covering material so as to follow the entire circumference of the outer edge of the covering material, and the fixing device is positioned around the object to be irradiated by the electron beam.

[0062] Furthermore, the present invention includes, as a preferred embodiment of the electron beam irradiation apparatus described in items 1 to 5 above, the electron beam irradiation apparatus described in item 6 below.

[0063] Item 6. The electron beam irradiation apparatus according to any one of items 1 to 5, wherein the size of the mounting device in a plan view is smaller than the size of the irradiation area of ​​the electron beam irradiated from the irradiation window of the apparatus body onto the mounting stand described above in a plan view.

[0064] Furthermore, the present invention includes, as a preferred embodiment of the electron beam irradiation apparatus described in items 1 to 6 above, the electron beam irradiation apparatus described in item 7 below.

[0065] Item 7. The electron beam irradiation apparatus according to any one of items 1 to 6, wherein the height of the mounting device is 3 cm or less.

[0066] Furthermore, the present invention includes, as a preferred embodiment of the electron beam irradiation apparatus described in items 1 to 7 above, the electron beam irradiation apparatus described in item 8 below.

[0067] Item 8. The electron beam irradiation apparatus according to any one of items 1 to 7, wherein the covering material is flexible.

[0068] Furthermore, the present invention includes, as a preferred embodiment of the electron beam irradiation apparatus described in items 1 to 8 above, the electron beam irradiation apparatus described in item 9 below.

[0069] Item 9. The electron beam irradiation apparatus according to any one of items 1 to 8, wherein the covering material is made of metal.

[0070] Furthermore, the present invention includes, as a preferred embodiment of the electron beam irradiation apparatus described in paragraphs 8 and 9 above, the electron beam irradiation apparatus described in paragraph 10 below.

[0071] Item 10. The electron beam irradiation apparatus according to item 8 or 9, wherein the covering material is made of aluminum foil.

[0072] Furthermore, the present invention includes, as a preferred embodiment of the electron beam irradiation apparatus described in items 1 to 10 above, the electron beam irradiation apparatus described in item 11 below.

[0073] Item 11. The electron beam irradiation apparatus according to any one of items 1 to 10, further comprising a cooler for cooling the irradiation window with a cooling gas.

[0074] Furthermore, the protective cover of the present invention includes the protective cover described in Section 12 below in order to solve the problems of this disclosure.

[0075] Item 12. An electron beam irradiation apparatus for irradiating an object to be irradiated with an electron beam, which is placed on a mounting platform, wherein a protective cover is provided on the mounting platform described above for protecting the object to be irradiated with an electron beam, The device comprises a covering material that is permeable to the electron beam and covers the object to be irradiated by the electron beam, and at least one fixing device that is placed on the covering material so as to be along at least a portion of the outer edge of the covering material and presses the covering material toward the aforementioned base, The aforementioned mounting device is a protective cover having an internal passage through which a cooling fluid for cooling the mounting device flows, an inlet for introducing the cooling fluid into the internal passage, and an outlet for discharging the cooling fluid from the internal passage.

[0076] Furthermore, the method for protecting an object irradiated with an electron beam according to the present invention includes the method for protecting an object irradiated with an electron beam described in Section 13 below, in order to solve the problems of this disclosure.

[0077] Item 13. An electron beam irradiation apparatus for irradiating an object to be irradiated with an electron beam, which is placed on a mounting platform, wherein a method for protecting the object to be irradiated with an electron beam is provided on the mounting platform described above, The electron beam-permeable covering material is placed over the object to be irradiated by the electron beam. At least one mounting device is placed on the covering material so as to be along at least a portion of the outer edge of the covering material, and the covering material is pressed towards the mounting base described above. A method for protecting an object irradiated by an electron beam, characterized by circulating a cooling fluid inside the aforementioned fixing device to cool the fixing device. [Explanation of Symbols]

[0078] 1 Electron beam irradiation device 2 Irradiated object 3. Main unit of the device 4 Irradiation room 5. Mounting platform 6 Protective cover 7 Covering material 8. Fixing material 9 Fixing means 10 Cooler 80 Internal flow path 81 Inlet 82 Outlet 30 Irradiation window section 31 Metal foil

Claims

1. An electron beam irradiation apparatus comprising at least an irradiation chamber equipped with a platform for placing an object to be irradiated by an electron beam, and a main body of an apparatus that generates an electron beam and irradiates the object to be irradiated by an electron beam from an irradiation window into the irradiation chamber, The mounting platform further includes a protective cover provided on the aforementioned mounting platform to protect the object to be irradiated by the electron beam, The protective cover comprises a covering material that is permeable to the electron beam and covers the object irradiated by the electron beam, and at least one fixing device that is placed on the covering material so as to be along at least a portion of the outer edge of the covering material. In the covering material, the portion on which the fixing device is placed is pressed against the aforementioned base by the fixing device. The aforementioned stationary device has an internal passage through which a cooling fluid for cooling the stationary device flows, an inlet for introducing the cooling fluid into the internal passage, and an outlet for discharging the cooling fluid from the internal passage, wherein the device is an electron beam irradiation apparatus.

2. The electron beam irradiation apparatus according to claim 1, wherein the fixing device is provided with fixing means for fixing the covering material to the fixing device in a portion facing the covering material.

3. The aforementioned fixing device has a flat lower surface facing the covering material, The electron beam irradiation apparatus according to claim 2, wherein the fixing means is provided on the lower surface of the fixing device.

4. The electron beam irradiation apparatus according to claim 2 or 3, wherein the fixing means is an adhesive, a tack, or double-sided tape.

5. The electron beam irradiation apparatus according to claim 1, wherein the fixing device has a frame-like shape in plan view and is placed on the covering material so as to follow the entire circumference of the outer edge of the covering material, and the fixing device is arranged around the object to be irradiated by the electron beam.

6. The electron beam irradiation apparatus according to claim 1, wherein the size of the fixed device in a plan view is smaller than the size of the irradiation area of ​​the electron beam irradiated from the irradiation window of the apparatus body onto the base described above in a plan view.

7. The electron beam irradiation apparatus according to claim 1, wherein the height of the aforementioned mounting device is 3 cm or less.

8. The electron beam irradiation apparatus according to claim 1, wherein the covering material is flexible.

9. The electron beam irradiation apparatus according to claim 1, wherein the covering material is made of metal.

10. The electron beam irradiation apparatus according to claim 8 or 9, wherein the covering material is made of aluminum foil.

11. The electron beam irradiation apparatus according to claim 1, further comprising a cooler for cooling the irradiation window portion with a cooling gas.

12. An electron beam irradiation apparatus that irradiates an object to be irradiated with an electron beam, which is placed on a mounting platform, wherein a protective cover is provided on the mounting platform to protect the object to be irradiated with an electron beam, The device comprises a covering material that is permeable to the electron beam and covers the object to be irradiated by the electron beam, and at least one fixing device that is placed on the covering material so as to be along at least a portion of the outer edge of the covering material and presses the covering material toward the aforementioned base, The aforementioned mounting device is a protective cover having an internal passage through which a cooling fluid for cooling the mounting device flows, an inlet for introducing the cooling fluid into the internal passage, and an outlet for discharging the cooling fluid from the internal passage.

13. An electron beam irradiation apparatus that irradiates an object to be irradiated with an electron beam, which is placed on a mounting platform, wherein a method for protecting the object to be irradiated with an electron beam is provided on the mounting platform described above, The electron beam-permeable covering material is placed over the object to be irradiated by the electron beam. At least one mounting device is placed on the covering material so as to be along at least a portion of the outer edge of the covering material, and the covering material is pressed towards the mounting base described above. A method for protecting an object irradiated by an electron beam, characterized by circulating a cooling fluid inside the aforementioned fixing device to cool the fixing device.

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