JPH0425799Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a klystron electron beam focusing device, and more particularly to an improvement of a uniform magnetic field electron beam focusing device using a permanent magnet.

Prior Art Klystron electron beam focusing devices generally use electromagnets or permanent magnets to generate a magnetic field consisting of magnetic flux parallel to the axis of the electron beam, and impart rotational motion to the electrons forming the electron beam. The electron beam is configured to prevent divergence of the electron beam due to repulsive force between electrons, and to maintain an approximately constant diameter of the electron beam in the path from the electron gun to the collector.

When using permanent magnets as the magnetic field generating means of the electron beam focusing device, one set of permanent magnets is placed on the electron gun side and one set of permanent magnets is placed on the collector side along the electron beam flow of the klystron. are magnetically connected to each other by a yoke, respectively, and configured to form a desired magnetic field in the klystron located at the center thereof.

At this time, if the axis of the klystron's electron beam and the axis of the magnetic flux of the electron beam focusing device do not match, the electron beam will bend in a direction perpendicular to the axis, and some of the electrons leaving the electron gun will collides with the klystron's high-frequency circuit, causing unnecessary heat generation or, in extreme cases, electrode damage.

For this reason, when manufacturing a klystron, after combining the klystron and an electron beam focusing device, the amount of electrons flowing into the high-frequency circuit of the klystron is measured and monitored as a current, and an appropriate part of the magnetic circuit is connected to the klystron. It was necessary to adjust the current to a minimum by placing a small iron piece or the like in the position.

Problems to be Solved by the Invention However, if a magnetic disturbance occurs to the adjusted klystron and electron beam focusing device assembly, for example, a ferromagnetic material or other magnet may If the electron beam approaches or comes into contact with the electron beam, the magnetic field of the electron beam focusing device changes, and as a result, the electron beam cannot pass through the klystron's high-frequency circuit section.

In particular, if a ferromagnetic tool or part comes into contact with the permanent magnet due to the carelessness of an assembly worker or product handler, the contact area of the permanent magnet may be demagnetized. A so-called contact demagnetization phenomenon occurred, causing a significant change in the magnetic field formed within the klystron.

Tools and the like are rarely made of non-magnetic materials mainly due to their strength, and it is virtually impossible to eradicate accidents such as those mentioned above where a ferromagnetic material comes into contact with a permanent magnet.

The present invention eliminates such inconveniences, and by providing a protective means for the permanent magnets in the magnetic circuit, even if a ferromagnetic material comes into contact with the permanent magnets of the klystron's electron beam focusing device, extreme changes in magnetic properties do not occur. An object of the present invention is to provide an electron beam focusing device for a klystron.

Means for Solving the Problems According to the present invention, at least a pair of permanent magnets are spaced apart from each other along the flow of an electron beam of a klystron, and an end of the permanent magnets opposite to the klystron is magnetically connected. An electron beam focusing device for a klystron, comprising: a yoke coupled to the klystron; An electron beam focusing device for a klystron is provided, which is characterized in that it includes a protective member made of a material.

Effect If a protective member is attached to the permanent magnet of the electron beam focusing device according to the present invention, contact demagnetization will not occur even if a ferromagnetic material comes into contact with the electron beam focusing device, and the magnetic properties of the magnetic field produced by the electron beam focusing device will not occur. does not change drastically.

EXAMPLES Next, the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing one embodiment of an electron beam focusing device according to the present invention.

In FIG. 1, one set of permanent magnets 2 is arranged on the electron gun side of the klystron 1, and one set of permanent magnets 3 is arranged on the collector side of the klystron 1.
are coupled by a pair of ferromagnetic yokes 4 that magnetically couple these permanent magnets 2 and 3,
A magnetic circuit is configured within the klystron 1 to generate a magnetic field parallel to the flow of the electron beam.

Of the outer peripheral surfaces of the permanent magnets 2 and 3, protective members 5 fixed with an adhesive or the like are attached to four surfaces other than the surface connected to the klystron 1 and the surface connected to the yoke 4. The protective members 5 attached to each of the four surfaces are continuous with the protective members 5 attached to the adjacent surfaces, respectively, to prevent the permanent magnet surface from being exposed.

Since the purpose of the protective member 5 is to prevent contact demagnetization with respect to the permanent magnet 2 or 3, the material is not limited as long as it is a non-magnetic material, and metal materials such as copper, copper, Aluminum, brass, etc. can be used, and aluminum is advantageous because of its small weight and ease of processing. Furthermore, it goes without saying that the material of the protective member 5 is not limited to metal materials, and non-magnetic materials such as silicone rubber can also be used.

FIG. 2 is a perspective view of one of the permanent magnets taken out and showing how the protective member is attached.

In FIG. 2, four of the six surfaces of the permanent magnet 2, excluding the surface 10 connected to the klystron 1 and the surface connected to the yoke 4 (the side that cannot be seen with the permanent magnet in FIG. 2), are shown. It is shown that mutually connected protection members 5 are provided.

In this embodiment, the protective members 5 are attached to each surface of the permanent magnets 2 and 3, but it is also possible to reduce the number of assembly steps by using protective members 5 that are integrally formed in advance to match the shape of the permanent magnets. can.

Furthermore, in the embodiment shown in FIG.
Although the protective member 5 is adhesively fixed to the permanent magnet, it can also be easily disassembled and assembled using screws or the like.

Effects of the Invention As described in detail above, the electron beam focusing device according to the present invention is able to maintain the relationship between the permanent magnet and the ferromagnetic material even if a careless operator accidentally comes into contact with tools or parts made of ferromagnetic material. Since the protective member is interposed, it is possible to reduce changes in the characteristics of the permanent magnet due to contact demagnetization, and it is possible to prevent extreme changes in the magnetic characteristics of the electron beam focusing device.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the electron beam focusing device according to the present invention, and FIG. 2 is a sectional view showing one of the permanent magnets of the electron beam focusing device according to the present invention and a state in which a protective member is attached. FIG. (Main reference number), 1...Klystron, 2,
3... Permanent magnet, 4... Yoke, 5... Protective member.

Claims (1)

[Claims for utility model registration] Along the flow of the klystron electron beam,
An electron beam focusing device for a klystron, comprising at least a pair of permanent magnets arranged apart from each other, and a yoke magnetically coupling ends of the permanent magnets opposite to the klystron, the permanent magnets comprising: An electron beam focusing device for a klystron, characterized in that a protective member made of a non-magnetic material is provided on each surface of the outer peripheral surface other than the surface connected to the yoke and the surface connected to the klystron.