JP2004239723A - Electron beam irradiator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a mechanism for fixing an object to be irradiated which has a simple structure that prevents the object from being curled up by cooling wind. <P>SOLUTION: The object to be irradiated is fixed onto a conveyor by equipping the mechanism with a suction mechanism for sucking the object from a lateral face of a plate beam catcher or somewhat below the lateral face of it. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electron beam irradiation apparatus.
[0002]
[Prior art]
[0003]
FIG. 2 shows a first conventional example. When the electron beam passes through the window foil 2, a part of the energy is lost and the window foil 2 generates heat. In order to prevent the window foil 2 from being damaged due to excessive heat generation, the cooling air 10 supplied from the cooling air duct 8 is blown onto the window foil 2 by the nozzle 9 to be cooled. Since the inside of the scanning tube 1 is in a vacuum state, the window foil 2 is recessed as shown in the figure, and the cooling air 10 from the nozzle 9 flows as shown by the arrows, and the irradiated sheet 5 is placed on the mesh conveyor 4 in the irradiation region. Is not passed through the mesh conveyor 4 and hits the beam catcher 6.
[0004]
Therefore, when the tip of the irradiated sheet 5 is placed on the mesh conveyor 4 and introduced into the irradiation region, a phenomenon occurs in which the tip of the irradiated sheet 5 is turned up by the cooling air 10 reversed by the beam catcher 6. . In general, an electron beam irradiation apparatus is configured such that the distance of the electron beam passage atmosphere layer from the window foil 2 to the irradiated sheet 5 is shortened in order to suppress generation of ozone and energy loss due to the electron beam. Therefore, the occurrence of a turn-up phenomenon at the tip of the irradiated sheet 5 hinders smooth operation of the electron beam irradiation apparatus.
[0005]
In order to solve the above problem, in the conventional example 2 of FIG. 3, the cooling air 10 is inverted by the beam catcher 16 by dividing the plurality of pipe-shaped beam catchers 16 and the lead target 17 below the mesh conveyor 4. The phenomenon that the tip of the irradiated sheet 5 is turned up by the cooling air 10 is reduced.
[0006]
Further, an exhaust device 19 is provided at the lower part of the mesh conveyor 4, and the exhaust gas is exhausted by the exhaust gas at the lower surface of the front end of the irradiated sheet 5, so that the front end of the sheet is in close contact with the mesh conveyor 4 and has a function of preventing turning. Further encouraged.
[0007]
Each beam catcher 16 is composed of a stainless steel pipe through which cooling water flows, and the lead target 17 has a circumference opposite to the side on which the electron beam of the beam catcher hits, so that the electron beam does not hit directly. It is attached to the face part. The plurality of beam catchers 16 are arranged side by side with an interval and a gap, respectively, and are arranged in, for example, two stages so that the electron beams passing through the gap between the beam catchers can be absorbed and captured. The lead target 17 is for absorbing radiation generated from the captured electron beam.
[0008]
As described above, the irradiation object 5 is turned up by the cooling air 10 of the window foil 2 and the window foil 2 is damaged, and the pipe-shaped beam catcher 16 and the exhaust device 19 (suction mechanism) are provided below the mesh conveyor 4. The tip of the irradiated sheet 5 is brought into close contact with the mesh conveyor 4 and prevented from being turned up by forcibly exhausting (suctioning) the atmospheric gas at the lower surface of the leading end of the irradiated sheet 5 that is provided and introduced into the irradiation region. Mechanisms that can do this have been proposed. (For example, see Patent Document 1.)
[0009]
[Patent Document 1]
Japanese Utility Model Publication No. 7-18300 (Claim 1, FIG. 1)
[0010]
However, in the above-mentioned conventional example 2, it is necessary to provide a gap between the beam catchers for the suction flow, and all of the beam cannot be caught by this gap, and the beam is placed in the suction mechanism. Hit and heat the suction mechanism. This heat dissipation requires a large space around the suction duct, which increases the size of the apparatus. In addition, the beam catcher needs to be a special mechanism.
The present invention provides a window foil cooled by cooling air, a transport device having a conveyor for transporting irradiated objects through which an air current passes, a plate beam catcher, and a side surface of the plate beam catcher. Alternatively, a suction mechanism for sucking the irradiated object from the side slightly below is provided.
[0011]
Furthermore, in order to realize a reduction in size and efficiency of the suction mechanism, a protrusion is provided on the surface of the beam catcher for the purpose of limiting the suction space. As a result, the irradiated object can be sucked even with a suction blower having a small suction capacity. Also, the same effect can be obtained by providing a depression on the surface of the beam catcher instead of the protrusion.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG. In addition, the part which attached | subjected the same code | symbol as FIG. 2 or FIG. 3 shows the same or corresponding part. The beam catcher 6 and the lead target 7 are plate-shaped. The beam catcher 6 is provided with a cooling water hole 23 in order to reduce heat generation. A suction duct 20 is provided on the side surface of the plate-shaped beam catcher or slightly below the side surface.
[0013]
The cooling air 10 reversed by the beam catcher 6 generates a force for turning up the irradiated object 5. However, the irradiated object 5 can be attracted to the transport device 4 by the suction flow 22 from the suction mechanism 19. It will be lost.
[0014]
The irradiation object 5 is turned up by the cooling air 10 when it is placed on the conveyor 4 and the leading end of the irradiation sheet 5 is introduced into the irradiation region. Is weak. That is, if the portion conveyed toward the center of the scanning tube 1 is fixed with a downward force, the irradiated object cannot be turned up. The downward force is realized by the suction mechanism 19.
[0015]
In order to generate the suction flow 22 efficiently, a wall is provided by a protrusion on the beam catcher as shown in FIGS. Thereby, since the suction target range is limited, the capacity of the suction blower can be reduced. Similarly, the same effect can be obtained by providing a recess in a part of the beam catcher as shown in FIGS.
[0016]
The conveying device 4 for passing the airflow is realized by using a mesh structure in a portion where the irradiated object 5 is placed or by opening a plurality of holes. For this reason, the irradiated object 5 can be fixed to the transport device 4 by the suction flow 22.
[0017]
The plate-shaped beam catcher may be realized by a single plate, but can also be realized by arranging commercially available square pipes in a line. This method eliminates the need for special processing of the cooling water holes 23 and contributes to cost reduction.
【The invention's effect】
As described above, according to the present invention, since a plate-shaped beam catcher can be used, it is possible to realize an electron beam irradiation apparatus including a simple structure for preventing the irradiation sheet from being turned over. According to the present invention, it is possible to easily add a suction mechanism to a product that has already been delivered.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view of Conventional Example 1.
FIG. 3 is a cross-sectional view of Conventional Example 2.
FIG. 4 is a top view of a projection-type beam catcher of the present invention.
FIG. 5 is a side view of a projection-type beam catcher according to the present invention.
FIG. 6 is a top view of a hollow type beam catcher of the present invention.
FIG. 7 is a side view of a hollow type beam catcher of the present invention.
[Explanation of symbols]
1 Scanning tube 2 Window foil 4 Conveyor (mesh conveyor)
5 Object to be irradiated (irradiated sheet)
6 Beam catcher 7 Lead target 9 Cooling air nozzle 10 Cooling air 19 Suction mechanism (exhaust device)
20 Suction duct (exhaust duct)
21 Suction blower (exhaust blower)

Claims (2)

Window foil cooled by cooling air;
A transport device having a conveyor for transporting irradiated objects through which an air current passes;
A plate beam catcher,
An electron beam irradiation apparatus provided with a suction mechanism for sucking an object to be irradiated from the side or side of the plate-shaped beam catcher or slightly below. The electron beam irradiation apparatus according to claim 1, wherein the plate-like beam catcher is provided with a protrusion or a depression.

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