JPH0718299U - Electron beam irradiation device - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the spread of the electron beam due to the magnetic flux of the transformer. [Structure] An air-core transformer 2 housed in a pressure tank 1 has a primary coil 3 and a secondary coil 4, and a thermoelectron emission filament 6 and an accelerating tube 7 are arranged at the center of the transformer. ing. The primary coil portion 3 ₁ located at the height from the filament arrangement position h ₁ which determines the orbit of the electron beam to the arrangement position h ₂ of the fifth-stage accelerating electrode 8 in the accelerating tube is attached to the central axis Z of the accelerating tube. Place it in parallel with. The magnetic flux of the transformer in the part that determines the trajectory of the electron beam becomes more parallel to the central axis line, the magnetic flux component in the direction perpendicular to the coaxial line decreases, and the spread of the electron beam is reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electron beam irradiation apparatus having an air-core transformer type high voltage power source that reduces the spread of electron beam trajectories.

[0002]

[Prior art]

 FIG. 2 is a schematic cross-sectional configuration diagram of an electron beam irradiation apparatus having a high voltage power source configured by using an air core transformer. An air-core transformer 2 is contained in a pressure vessel 1 filled with high-voltage insulating gas, and a secondary coil 4 is provided inside a primary coil 3 which is wound in a conical or tapered shape as a whole. There is. The secondary coil is configured by stacking a large number of coils 4 in multiple stages in the central axis direction of the primary coil 3.

The primary coil 3 is opposed to the secondary coil 4 so that a required insulation distance is provided between the coil of the low voltage stage located in the lower stage of the secondary coil 4 and the coil of the high voltage stage located in the upper stage. The portion is arranged in a tapered shape. A magnetic shield member 5 is provided so as to surround the outside of the primary coil 3, and the shield member serves as a passage for the coil magnetic flux generated outside the primary coil. Rectifier circuits (not shown) are provided inside the secondary coils 4, and each rectifier circuit rectifies the induced voltage of each secondary coil 4 and connects the DC output terminals of each rectifier circuit in series. By doing so, a direct current high voltage is obtained.

A filament 6 for generating thermoelectrons and an accelerating tube 7 are arranged inside the secondary coil 4 and in the center of the air-core transformer 2. The DC high voltage obtained by rectifying the induced voltage of the secondary coil 4 is applied to the filament 6 and each accelerating electrode 8 of the accelerating tube 7 by resistance division.

[0005]

[Problems to be solved by the device]

Since the primary coil 3 in the air-core transformer 2 is arranged in a taper shape, the magnetic flux generated by the primary coil inside the secondary coil 4 is in the center axis Z of the air-core transformer 2 and the acceleration tube 7. Has an angle to the opposite. The magnetic flux also passes inside the accelerating tube 7, and the magnetic flux φ in the vicinity of the central axis also has a certain angle θ with respect to the central axis Z, as shown in FIGS. Will have the component φr = φsin θ. Due to this magnetic flux component φr, a force F for expanding the electron beam is generated in the direction orthogonal to the magnetic flux component φr with respect to the electron beam e ⁻ traveling from the filament 6 in the acceleration tube 7. When the electron beam spreads, the electron beam hits the accelerating electrode 8 of the accelerating tube 7 and the inside of the scanning tube 9 connected to the lower end of the accelerating tube during deflection scanning of the electron beam, so that the irradiation electron beam is sufficiently obtained. There will be a situation where it is not possible.

An object of the present invention is to provide an electron beam irradiation apparatus having an air-core transformer type high voltage power source capable of reducing the spread of the electron beam.

[0007]

[Means for Solving the Problems]

 The present invention relates to an air-core transformer type high-voltage power source, an electron beam irradiation device having a thermoelectron generating filament and an accelerating tube respectively arranged at the center of the air-core transformer. It is characterized in that the primary coil of the air-core transformer located at a height up to the position where the fifth-stage accelerating electrode is arranged in the accelerating tube is arranged parallel to the central axis of the accelerating tube. .

[0008]

[Action]

 The magnetic flux φ generated between the filament that determines the orbit of the electron beam and the fifth-stage accelerating electrode of the accelerating tube becomes close to parallel to the Z axis, and the spread of the electron beam is reduced.

[0009]

【Example】

An embodiment of the present invention will be described with reference to the sectional configuration diagram of FIG. The same reference numerals as those in FIG. 2 indicate the same parts. When accelerating an electron beam, its orbit is generally strongly affected by the lens action at the entrance of the accelerating tube. In this respect, it is desirable to minimize the spread of the electron beam in the part that determines the trajectory of the electron beam. The filament 6 and the accelerating tube 7 are arranged in the center of the inner side of the secondary coil 4 of the air-core transformer 2, and the accelerating electrode at the fifth stage of the accelerating tube from the filament arranging position h ₁ that determines the trajectory of the electron beam. the position h ₂ up to a height corresponding to the position the primary coil 3, that is, the coil unit content of 3 _1, the winding arrangement without the tapered accelerating tube Therefore the central axis of the air-core transformer 2 The central axis of 7 and the Z axis are made parallel. The coil portion 3 ₂ below the coil portion 3 ₁ and the coil portion 3 ₃ above the coil portion 3 ₁ are wound and arranged in a tapered shape in the same manner as in the conventional device so that the electrical insulation from the secondary coil 4 is maintained.

By arranging the coil portion 3 ₁ parallel to the central axis of the accelerating tube 7 in the primary coil 3 in this way, the magnetic flux φ from the filament 6 to the fifth stage of the accelerating electrode 8 in the accelerating tube is The magnetic flux component φr in the direction perpendicular to the Z axis shown in Fig. 3 can be reduced because it becomes closer to the Z axis, and therefore the electron beam based on the magnetic flux component at the location that determines the trajectory of the electron beam can be reduced. Spread is reduced.

For the coil portion 3 ₁ of the primary coil 3 which is parallel to the Z axis, the number of turns is increased and the magnetic flux component parallel to the Z axis is increased, which is further advantageous in reducing the spread of the electron beam.

[0012]

[Effect of device]

 Since the present invention is configured as described above, the magnetic flux generated from the filament that determines the orbit of the electron beam to the fifth stage position of the accelerating electrode in the accelerating tube becomes close to the central axis and the Z axis. , It is possible to suppress the generation of the magnetic flux component in the direction perpendicular to the Z axis, so that the spread of the electron beam due to the magnetic flux component can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of an embodiment of the present invention.

FIG. 2 is a sectional configuration diagram of a conventional example.

FIG. 3 is an explanatory diagram of generated magnetic flux.

[Explanation of symbols]

1 pressure vessel 2 air-core transformer 3 primary coil 3 ₁ parallel to the central axis of the primary coil portion 4 secondary coil 5 the magnetic shield member 6 filament 7 the accelerating tube 8 accelerating electrode

Claims (1)

[Scope of utility model registration request] 1. An electron beam irradiation apparatus having an air-core transformer type high-voltage power source, a thermoelectron generating filament and an accelerating tube respectively disposed at the center of the air-core transformer, wherein the filament is arranged from the position where the filament is arranged. Electron beam irradiation, characterized in that the primary coil of the air-core transformer, which is located at a height up to the arrangement position of the fifth-stage accelerating electrode in the accelerating tube, is arranged parallel to the central axis of the accelerating tube. apparatus.