CN104269334A - Electron gun producing tape-shaped or high-ellipticity electron beams - Google Patents

Abstract

The invention discloses an electron gun for producing banded or high ellipticity electron beams, which belongs to the technical field of vacuum electrons. Firstly, according to the thickness of the required strip-shaped electron beam as the diameter, a suitable cylindrical electron beam electron gun is designed by a mature method, and then the focusing electrode and the anode of the electron gun are evenly divided into two halves, and the same widening as the split section is added in the middle part, the length of the extended part is determined according to the required width of the electron note. At this time, the focusing pole forms a semicircular ring at both ends, and an oblate electron gun focusing pole and anode in the middle of which is a widened part. Its focus field is consistent with the topological structure of the space charge field of the electron beam, and the problem of certain angle diffusion and certain angle staggering mentioned in the background technology will not occur, and the laminar flow of the ribbon electron beam will not be interrupted, so that the electron beam successfully reached the anode.

Description

An electron gun for producing banded or high ellipticity electron beams

technical field

The invention belongs to the technical field of vacuum electronics, and relates to traveling wave tubes, back wave tubes, back wave oscillators, klystrons, free electric

Vacuum electronic devices such as sub-lasers and Oro tubes.

Background technique

With the advancement of science and technology, the demand for vacuum electronic devices tends to be higher in power and frequency. Therefore, strip-shaped electron beams or high ellipticity electron beam vacuum electronic devices that can generate high current, high power, and high frequency output have become the domestic other research hotspots. However, vacuum electronic devices using ribbon electron beams, such as ribbon electron beam traveling wave tubes, back wave tubes, klystrons, free electron lasers, and Oro tubes, all face a key problem—how to realize high-quality ribbon beam beams. launch. The existing cylindrical or pencil-shaped electron focusing pole has a ring-shaped structure, and its central hole is funnel-shaped. The cylindrical cathode is located at the bottom of the funnel-shaped central hole of the focusing pole of the ring structure, and the cathode emits electrons, which are focused by the focusing pole. Afterwards, it passes through the anode with a circular hole, thus forming a cylindrical electron beam. The ribbon-shaped electron beam is formed by the emission of a rectangular cathode or an elliptical cathode. When the conventional circular focusing pole is used to focus the ribbon-shaped electron beam, the space charge force on the cross-section of the ribbon-shaped electron beam is distributed differently along the angle, while the circular electron beam The focusing force of the focusing pole is the same in all directions of the angle on its cross section, so that the electron beams intersect in the angle direction where the focusing force is greater than the space charge force, and diffuse in the angle direction where the focusing force is smaller than the space charge force, and it is impossible to realize the band Focusing and stabilization of the electronic note.

Contents of the invention

In order to realize the focusing and control of the ribbon-shaped electron beam, the present invention proposes an energy-saving, high-efficiency electron gun for ribbon-shaped or high ellipticity electron beam vacuum electronic devices.

The technical solution adopted in the present invention is: firstly, according to the thickness of the required strip-shaped electron beam as the diameter, design a suitable cylindrical electron injection gun through a mature method, and then divide the focusing pole and the anode of the electron gun into two halves on average, Add the same widening part as the split section in the middle, and the length of the widening part is determined according to the required electron beam width. At this time, the focusing pole forms a semicircular ring at both ends, and a flattened circular electron gun focusing pole and anode in the middle. Its focusing field is consistent with the topological structure of the space charge field of the electron beam, and the problem of certain angle diffusion and certain angle staggering mentioned in the background technology will not occur, and the laminar flow of the ribbon electron beam will not be interrupted, so that the electron beam Smoothly reach the anode, so that the emission of high-quality band-shaped electron beams can be realized, which is the purpose of the present invention.

Therefore a kind of electron gun that the present invention proposes to produce banded or high ellipticity electron beam comprises: cathode, focusing pole, anode, it is characterized in that, the outward appearance of focusing pole is the cylindrical structure of ellipse ring, and the middle section of this ellipse is parallel, two The ends are two semi-circular rings, the central hole of the focusing pole ring structure is funnel-shaped; the anode is an elliptical ring structure, and the cross-section of the central hole is the same everywhere; the cathode is a metal sheet, which is set at the bottom of the funnel-shaped central hole of the focusing pole .

The cathode is a metal sheet with a rectangle or a semicircle at both ends and a rectangle in the middle, and its area is smaller than that of the bottom surface of the center hole of the focusing pole.

Advantages: Since the focusing pole has an oblate structure, the formed focusing electric field is also oblate, that is, it is consistent with the space charge field topology of the banded electron beam or the high ellipticity electron beam, so when using the focusing pole structure, no Breaking the laminarity of the ribbon-shaped electron beam can obtain a high-quality electron beam. However, when the traditional circular focusing pole-focusing strip electron beam is used, due to the mismatch between the focusing field and the space charge force field, the focusing field is larger than the direction of the space charge field, that is, the direction of the electron beam width, and the electrons become narrower and staggered. However, the focus field is smaller than the direction of the space charge field, that is, the direction of the thickness of the electron beam, and the electron beam diffuses, so high-quality electron beam cannot be obtained.

Secondly, because the quality of the electron beam generated by the focusing electrode is better, in the same electric vacuum device, the flow rate of the electron beam is higher, which can generate higher output and have higher efficiency.

Thirdly, the focusing pole with integrated processing also has the advantages of low cost and easy assembly.

Description of drawings

Fig. 1 is a schematic diagram of the focal point of the ribbon electron focus;

Fig. 2 is a sectional view of a strip-shaped electron focusing focal pole;

Figure 3 is a schematic diagram of a 11mm*1mm strip-shaped electron focus electrode;

Fig. 4 is a schematic diagram of a 12mm*1mm strip-shaped electron focus electrode.

In the figure: 1. cathode, 2. widening part, 3. extension surface, 4. slope.

Detailed ways

According to the required electron beam thickness, voltage, current and other parameters, select a mature circular cylindrical focus electrode, the waist of which is equal to the required strip electron beam thickness. The focusing pole is split, and the split section can be divided into two parts: 1) The inclined plane forming about 157.5 degrees with the cathode surface. 2) is an extension surface for controlling the electric field intensity on the surface of the cathode. Calculate the length of the slope, the length and thickness of the extended face. According to the width of the required ribbon-shaped electron beam, a widened structure with consistent cross-section is processed, and the length of the expanded structure is equal to the required width of the ribbon-shaped electron beam. In this way, the widening structure and the two semicircular focusing poles at both ends constitute the focusing pole applied to the focusing of the belt-shaped electron beam. The cathode adopts a rectangular middle section with semicircular ends, the anode adopts a ring structure with a parallel middle section and semicircular rings at both ends, and the cross section of the center hole is the same everywhere. Apparently, if the widening structure and the semicircular focusing poles at both ends can be integrally processed to form the focusing pole, it also falls within the protection scope of this patent.

Embodiment 1: as shown in Figure 3, focusing pole slope (angle 60 °, high 5mm), extension surface (high 7mm), widening structure length 10mm, corresponding cylindrical focusing pole can realize 0.5mm radius cylindrical electron injection, so The strip-shaped electron beam can realize a strip-shaped electron beam with a width of 11 mm and a thickness of 1 mm.

Embodiment 2: as shown in Figure 4, the focusing pole slope (angle 50 °, high 4mm), the extended surface (high 6mm) widening structure is long 12mm, and the corresponding cylindrical focusing pole can realize the cylindrical electron injection of 0.5mm radius, in order to realize Completely rectangular surface emission, the original cylindrical cathode part is replaced by the focusing electrode, so the strip-shaped electron beam can realize a strip-shaped electron beam with a width of 12mm and a thickness of 1mm.

Claims (2)

1. produce an electron gun that is banded or high ellipticity electron beam, comprising: negative electrode, focusing electrode, anode, is characterized in that, the outward appearance of focusing electrode is the column construction of oval ring-type, this oval stage casing is parallel, and two ends are two semicircular ring, and the centre bore of focusing electrode circulus is funnel-form; Anode is elliptical annular structure, and its centre bore everywhere cross section is identical; Negative electrode is sheet metal, is arranged at bottom focusing electrode funnel-form centre bore.

2. a kind ofly produce electron gun that is banded or high ellipticity electron beam as claimed in claim 1, it is characterized in that the described negative electrode sheet metal that to be rectangle or two ends be for rectangle in the middle of semicircle, its area is less than the area of focusing electrode centre bore bottom surface.