CN112992629A

CN112992629A - Transmission-type ray tube

Info

Publication number: CN112992629A
Application number: CN201911297486.9A
Authority: CN
Inventors: 刘骏; 王刘成; 张伟
Original assignee: Wuxi Unicomp Technology Co ltd
Current assignee: Wuxi Unicomp Technology Co ltd
Priority date: 2019-12-17
Filing date: 2019-12-17
Publication date: 2021-06-18

Abstract

The invention relates to the technical field of ray tubes, in particular to a transmission-type ray tube, which comprises: one end of the shell is sealed with the electrode, and the other end of the shell is sealed with the beryllium window; the anode is arranged on the beryllium window of the shell and comprises a layer of metal film plated on the inner side of the beryllium window; the cathode is arranged in the shell and comprises a filament and a plurality of layers of cathode stages, the filament and the cathode stages are respectively electrically connected with the electrode, the filament emits electron beams, and the electron beams are accelerated and focused by the plurality of layers of cathode stages and then are converged on an anode target surface to form micron-sized X-ray focal spots; the power supply is electrically connected with the filament and provides energy for the filament to enable the filament to emit electron beams.

Description

Transmission-type ray tube

Technical Field

The invention relates to the technical field of ray tubes, in particular to a transmission type ray tube.

Background

The transmission type X-ray tube is a new type of X-ray tube having high radiation generation efficiency and irradiation flux density. It abandons the reflective thick target, but selects the transmission target whose thickness can be accurate to several micrometers, and the X-ray can be directly passed through the thin target and projected from window, and its energy loss is very small. The anode structure of the transmission type X-ray tube is special, heat is easy to gather at the anode and difficult to dissipate heat, the target material at the anode end is only a layer of metal film directly plated on the inner side of the beryllium window, the energy of X-rays emitted by the conventional X-ray tube is very high, and the loss of the target surface of the metal film is easily caused when the X-ray tube is hit on the target surface, so that the X-ray tube is scrapped.

Disclosure of Invention

The invention aims to provide a transmission-type ray tube, which aims to solve the problem that the target surface of an anode metal film is easy to lose in the prior art.

In order to achieve the purpose, the invention provides the following technical scheme: a transmission-type ray tube comprising: one end of the shell is sealed with the electrode, and the other end of the shell is sealed with the beryllium window; the anode is arranged on the beryllium window of the shell and comprises a layer of metal film plated on the inner side of the beryllium window; the cathode is arranged in the shell and comprises a filament and a plurality of layers of cathode stages, the filament and the cathode stages are respectively electrically connected with the electrode, the filament emits electron beams, and the electron beams are accelerated and focused by the plurality of layers of cathode stages and then are converged on an anode target surface to form a micron-sized X-ray focal spot; and the power supply is electrically connected with the filament and provides energy for the filament to enable the filament to emit electron beams.

Preferably, each of the cathode stages is individually electrically connected to an electrode.

Preferably, the cathode level piece is a five-level piece, and the five-level piece sequentially comprises a public end level, a grid control level, an acceleration level, a focusing A level and a focusing B level from right to left.

Preferably, a coil is wound around the outside of the case.

Preferably, the offset coils are uniformly distributed on the outer side of the shell in the circumferential direction.

Preferably, the electrode is a ceramic electrode.

Compared with the prior art, the invention has the beneficial effects that: the multi-layer cathode grade sheet can accelerate and gather the divergent electron beams emitted by the filament to the micron level to hit the target surface of the anode, and then micron-level X-ray focal spots are generated, and the electron beams are converged to the micron level to hit the target surface, so that the loss of the anode film can be reduced, and the service life of the whole ray tube is prolonged; the coil is wound on the outer side of the shell, so that the focusing of the electron beam and the control of the focal spot size can be increased; the circumferentially arranged offset coils of the housing may control the deflection of the electron beam and thus the offset of the X-ray focal spot.

Drawings

FIG. 1 is a schematic structural view of the present invention;

fig. 2 is a schematic structural diagram of another view angle of the present invention.

In the figure: 1 electrode, 2 casing, 3 cathode, 4 coil, 5 beryllium window, 6 offset coil.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 and 2, the present invention provides a technical solution: a transmission-type ray tube comprising: the cathode comprises a filament and a plurality of layers of cathode 3 grade sheets, wherein the filament and the cathode 3 grade sheets are respectively electrically connected with the electrode 1 through leads, the filament is also connected with the power supply through leads, the power supply provides energy for the filament to enable the filament to emit electron beams, the electron beams are accelerated and focused by the plurality of layers of cathode 3 grade sheets to be converged on an anode target surface to form micron-sized X-ray focal spots, the plurality of layers of cathode 3 grade sheets can accelerate and converge divergent electron beams emitted by the filament to a micron-sized target surface of the anode and then generate the micron-sized X-ray focal spots, and the electron beams are converged to the micron-sized target surface to reduce the loss of the anode film, the service life of the whole ray tube is prolonged.

Preferably, each of the cathode 3-level pieces is separately electrically connected with the electrode 1, each of the cathode 3-level pieces has a lead wire led out from the electrode 1, and the current voltage of each of the cathode 3-level pieces can be separately controlled.

In this embodiment, the cathode 3-level sheet is a five-level sheet, the five-level sheet is sequentially a common end level, a gate control level, an acceleration level, a focusing level a and a focusing level B from right to left, wherein the common end level is used as the common level of the five-level sheet, so that the five-level sheet becomes a large lens to perform an integral action, a small hole is formed in the middle of the gate control level to control the size of an electron beam and prevent high-speed electrons from impacting a tube wall, the acceleration level is controlled by external voltage to provide an acceleration when the electron beam passes through the central small hole, the focusing level a and the focusing level B focus the electron beam twice to impact an anode target surface, the energy generated when the micron-level electron beam impacts the target surface is very low, the loss of the target surface is very small, and the service life of the tube is greatly prolonged.

Preferably, a coil 4 is wound around the outside of the housing 2 to further focus the electron beam and control the size of the focal spot, which can prevent the target surface from burning out due to local overheating.

Preferably, the outer side of the housing 2 is circumferentially and uniformly distributed with offset coils 6, in this embodiment, 4 offset coils 6 are uniformly distributed, and the offset coils 6 can control the deflection of the electron beam, so as to control the offset of the X-ray focal spot.

The cathode 3 in the ray tube provided by the application is provided with the multilayer cathode 3-level pieces, the multilayer cathode 3-level pieces can accelerate and gather divergent electron beams emitted by the filament to a micron-level target surface of an anode, and then micron-level X-ray focal spots are generated, the electron beams are gathered to the micron-level target surface, so that the loss of an anode film can be reduced, and the service life of the whole ray tube is prolonged; the coil 4 is surrounded on the outer side of the shell 2, so that the focusing of the electron beam and the control of the focal spot size can be increased; circumferentially arranged deflection coils 6 of the housing 2 may control the deflection of the electron beam and thus the deflection of the X-ray focal spot.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A transmission-type ray tube, comprising:

one end of the shell (2) is sealed with the electrode (1), and the other end of the shell is sealed with the beryllium window (5);

the anode is arranged on the beryllium window (5) of the shell (2), and comprises a layer of metal film plated on the inner side of the beryllium window (5);

the cathode (3) is arranged in the shell (2), the cathode (3) comprises a filament and a plurality of layers of cathode (3) stages, the filament and the cathode (3) stages are respectively and electrically connected with the electrode (1), the filament emits electron beams, and the electron beams are accelerated and focused by the plurality of layers of cathode (3) stages and then are converged on an anode target surface to form a micron-sized X-ray focal spot;

and the power supply is electrically connected with the filament and provides energy for the filament to enable the filament to emit electron beams.

2. A transmission ray tube according to claim 1 wherein: each of the cathode (3) stages is individually electrically connected with the electrode (1).

3. A transmission ray tube according to claim 1 wherein: the cathode (3) level piece is a five-level piece, and the five-level piece sequentially comprises a public end level, a grid control level, an acceleration level, a focusing A level and a focusing B level from right to left.

4. A transmission ray tube according to claim 1 wherein: and a coil (4) is wound around the outer side of the shell (2).

5. A transmission ray tube according to claim 1 wherein: and offset coils (6) are uniformly distributed on the outer side of the shell (2) in the circumferential direction.

6. A transmission ray tube according to claim 1 wherein: the electrode (1) is a ceramic electrode.