Single-energy X-ray tube based on cold cathode electron source

Abstract

The utility model discloses a single-energy X-ray tube based on a cold cathode electron source, which relates to the field of single-energy X-ray tubes, and comprises a target body part, a cathode electron source part and an X-ray tube part, the anode target is a cylinder formed by embedding high-Z metal (5) into the surface of copper (6), the secondary target is formed by depositing carbon nanotubes on a fluorescent material flat plate of the cathode (4), and the fluorescent material flat plate is used as a cold cathode; and the shell part comprises a vacuum shell (1), a lead seal (2) and a beryllium window (7). The single-energy X-ray tube solves the problem that an existing single-energy X-ray tube needs a complex electronic optical system.

Description

Technical Field

[0001] The utility model relates to the field of single-energy X-ray tubes, in particular to a single-energy X-ray tube based on a cold cathode electron source. Background Art

[0002] X-rays are widely used in diagnostic imaging and radiation-based cancer therapy. High-end medical imaging equipment plays a significant role in medical testing for tuberculosis, breast cancer, and brain tumors. The X-ray source used in diagnostic radiology equipment consists of an accelerated electron beam directed toward an anode target, generating bremsstrahlung radiation and characteristic X-rays. Bremsstrahlung is the radiation emitted when a charged particle suddenly decelerates upon colliding with an atom or nucleus. Acceleration or deceleration of charged particles is inherently accompanied by electromagnetic radiation. Bremsstrahlung radiation produced by electrons that follow a Maxwell distribution is called thermal radiation. The X-ray spectrum of bremsstrahlung is often continuous, due to the continuously varying velocity of the charged particle under the electromagnetic field of the target nucleus. In medical diagnosis, high X-ray contrast is crucial to distinguish the signal between lesions and surrounding tissue. Since the X-ray absorption coefficient decreases with increasing energy, lower-energy X-rays provide higher contrast. However, using lower-energy X-rays results in a higher radiation dose absorbed by the patient, resulting in a smaller amount reaching the detector. This necessitates increasing the radiation dose to improve image clarity. Single-energy X-ray tubes have unique advantages in reducing radiation dose and improving imaging contrast.

[0003] Traditional X-ray tubes use hot cathodes, which emit electrons by heating the cathode. These electrons are then accelerated by an accelerating electric field and bombard the anode to produce X-rays. Cold cathode X-ray tubes, on the other hand, use a cold cathode to emit electrons by utilizing an electron field under high voltage. These electrons are then accelerated by an accelerating electric field and finally bombard the anode to produce X-rays. Cold cathode X-ray tubes can start and stop more quickly, saving time and energy. X-ray sources using hot cathodes typically have several inherent disadvantages. For example, due to the high temperature of the cathode, a cooling system is required. Hot cathode X-ray sources are typically large and unsuitable for miniaturized devices. Due to their slow response time, they have limited temporal resolution. Hot cathodes are often made of specific materials. These disadvantages limit the size, speed, throughput, and overall design flexibility of X-ray imaging systems.

[0004] Since the process of electron bombardment of the anode target to produce bremsstrahlung generates a large amount of heat, it is necessary to make the electron beam bombard the anode target as uniformly as possible. The existing design of the single-energy X-ray tube uses an annular permanent magnet to form an electron optical system, which makes the electron beam diverge and bombard the anode target uniformly, resulting in a complex structure of the single-energy X-ray tube. Utility Model Content

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a single-energy X-ray tube based on a cold cathode electron source, which solves the problem that the existing single-energy X-ray tube requires a complex electron optical system.

[0006] In order to achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is: a single-energy X-ray tube based on a cold cathode electron source, comprising:

[0007] Target body part: the target body part includes an anode target and a secondary target;

[0008] The anode target is a cylinder formed by embedding a high-Z metal into the surface of copper, and the secondary target is formed by depositing carbon nanotubes on a flat plate of fluorescent material of the cathode, while the flat plate of fluorescent material serves as a cold cathode;

[0009] Shell part: The shell part includes a vacuum shell, a lead seal and a beryllium window.

[0010] Furthermore, the cathode is a conical surface formed by two identical flat plates of fluorescent material, the cathode is located inside the anode target, and the anode target is located inside the vacuum housing.

[0011] Furthermore, the secondary target includes a grid, the grid is located outside the cathode, and the grid is located inside the anode target.

[0012] Furthermore, lead seals are provided at the openings on both sides of the anode target, an insulator is welded on the lead seal on one side, and the other end of the insulator is fixed to the secondary target by screws.

[0013] Furthermore, the beryllium window and the cathode are located at the same horizontal plane and embedded in the lead seal.

[0014] Furthermore, the single-energy X-ray tube is used in conjunction with a detector, and the detector is located outside the vacuum housing and on the same horizontal plane as the cathode.

[0015] Furthermore, the vacuum housing is made of stainless steel.

[0016] Furthermore, the high-Z metal is tungsten, lead or gold.

[0017] Furthermore, the fluorescent material plate is made of silver, molybdenum or neodymium.

[0018] The beneficial effects of the present invention are as follows: the monoenergetic X-ray tube based on the cold cathode electron source proposed in this scheme does not require a complex electron optical system and has a simple structure; by depositing carbon nanotubes on the fluorescent material, it not only acts as a cathode to emit electrons, but also acts as a secondary target to generate fluorescent X-rays; using the cold cathode as the emission source not only has no hysteresis in the emission time, but also has low power consumption, high emission density, low emission voltage, high stability, and no need for heating; the fluorescent material is replaceable, and different monoenergetic characteristic X-rays can be selected for output. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the principle of a cold cathode monoenergetic X-ray tube.

[0020] Figure 2 This is a three-dimensional diagram of the key parts of a cold cathode monoenergetic X-ray tube.

[0021] Figure 3 This is a cross-sectional view of the key parts of a cold cathode monoenergetic X-ray tube.

[0022] Figure 4 This is the energy spectrum produced by the bremsstrahlung of a gold target.

[0023] Figure 5 It is the monoenergetic X-ray energy spectrum received by the detector.

[0024] Among them: 1. Vacuum shell; 2. Lead seal; 3. Gate; 4. Cathode; 5. High-Z metal; 6. Copper; 7. Beryllium window; 8. Detector; 9. Insulator. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] like Figure 1 As shown, a single-energy X-ray tube based on a cold cathode electron source comprises:

[0027] Target body part: the target body part includes an anode target and a secondary target;

[0028] The anode target is a cylinder formed by embedding a high-Z metal 5 on the surface of a copper 6, and the secondary target is formed by depositing carbon nanotubes on a fluorescent material plate of the cathode 4, while the fluorescent material plate serves as a cold cathode;

[0029] Shell part: The shell part includes a vacuum shell 1, a lead seal 2 and a beryllium window 7.

[0030] like Figure 2 and Figure 3 As shown, the cathode 4 is a conical surface formed by two identical fluorescent material flat plates. The cathode 4 is located inside the anode target, and the anode target is located inside the vacuum housing 1.

[0031] The secondary target includes a gate 3 , which is located outside the cathode 4 and inside the anode target.

[0032] Lead seals 2 are provided at the openings on both sides of the anode target. An insulator 9 is welded to the lead seal 2 on one side, and the other end of the insulator 9 is fixed to the secondary target by screws.

[0033] Lead is used as sealing material to prevent radiation leakage.

[0034] The beryllium window 7 is located at the same level as the cathode 4 and is embedded in the lead seal 2 .

[0035] The single-energy X-ray tube is used in conjunction with a detector 8 . The detector 8 is located outside the vacuum housing 1 and is on the same horizontal plane as the cathode 4 .

[0036] The vacuum housing 1 is made of stainless steel.

[0037] The high-Z metal 5 is made of tungsten, lead or gold. These metals have high melting points, high thermal conductivity and good heat dissipation performance, and can withstand high-energy electron bombardment and generate sufficiently strong X-ray radiation.

[0038] The fluorescent material plate is made of silver, molybdenum or neodymium.

[0039] In one embodiment of the present invention, a monoenergetic X-ray tube based on a cold cathode electron source comprises a cathode 4 and a gate 3 placed in a vacuum. The cathode 4 is a conical surface formed by two identical flat plates of fluorescent material. Carbon nanotubes are deposited on the fluorescent material, acting as a cold cathode to emit electrons. The fluorescent material also serves as a secondary target to generate fluorescent X-rays. The second portion comprises a high-Z metal 5 and copper 6 placed in a vacuum. The high-Z metal 5 is embedded in the surface of the copper 6 to form an anode target. A positive voltage is applied to the gate 3 to draw out an electron beam. Under the influence of a high-voltage electric field, the electron beam evenly bombards the conical surface of the anode target, generating high-flux, broad-spectrum bremsstrahlung radiation. These primary X-rays from the bremsstrahlung radiation react with the secondary target fluorescent material to generate fluorescent X-rays. A lead seal 2 effectively absorbs and blocks the broad-spectrum bremsstrahlung radiation generated by the anode target from being received by the detector 8, ensuring that the detector 8 receives only the fluorescent X-rays generated by the secondary target fluorescent material. The anode target surface is slightly larger than the irradiation surface of the electron beam to ensure that the entire electron beam bombards the anode target. The beryllium window 7 plays the role of sealing the vacuum and filtering out the low-energy L-shell characteristic X-rays.

[0040] like Figure 4 As shown, this is the energy spectrum generated by the gold target bremsstrahlung. α Line at 10.5kev, l β Line at 11.4keV, k αLine at 68.8keV, k β The line is at 77.9keV, which is consistent with the bremsstrahlung spectrum of the gold target. Figure 5 As shown in the figure, it is the single energy X-ray spectrum received by the detector. It can be clearly seen that the detector detects the k α Line at 22.1keV, k β The line is at 77.9 keV and has no other energies, which is consistent with the monoenergetic X-ray proposed in this scheme.

[0041] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the scope of protection of the present invention is not limited to such specific descriptions and embodiments. Those skilled in the art can, based on the technical teachings disclosed in this utility model, make various other specific variations and combinations that do not depart from the essence of the present utility model, and such variations and combinations are still within the scope of protection of the utility model.

Claims

1. A single-energy X-ray tube based on a cold cathode electron source, characterized in that: include: Target body part: the target body part includes an anode target and a secondary target; The anode target is a cylinder formed by embedding a high-Z metal (5) on the surface of a copper (6), and the secondary target is formed by depositing carbon nanotubes on a fluorescent material flat plate of the cathode (4), while the fluorescent material flat plate serves as a cold cathode; Shell part: The shell part includes a vacuum shell (1), a lead seal (2) and a beryllium window (7).

2. The single-energy X-ray tube based on a cold cathode electron source according to claim 1, characterized in that: The cathode (4) is a conical surface formed by two identical fluorescent material flat plates. The cathode (4) is located inside the anode target, and the anode target is located inside the vacuum housing (1).

3. The single-energy X-ray tube based on a cold cathode electron source according to claim 2, characterized in that: The secondary target comprises a grid (3), the grid (3) is located outside the cathode (4), and the grid (3) is located inside the anode target.

4. The single-energy X-ray tube based on a cold cathode electron source according to claim 3, characterized in that: Lead seals (2) are provided at the openings on both sides of the anode target, an insulator (9) is welded on the lead seal (2) on one side, and the other end of the insulator (9) is fixed to the secondary target by screws.

5. The single-energy X-ray tube based on a cold cathode electron source according to claim 4, characterized in that: The beryllium window (7) is located at the same level as the cathode (4) and is embedded in the lead seal (2).

6. The single-energy X-ray tube based on a cold cathode electron source according to claim 5, characterized in that: The single-energy X-ray tube is used in conjunction with a detector (8), and the detector (8) is located outside the vacuum housing (1) and is located at the same level as the cathode (4).

7. The single-energy X-ray tube based on a cold cathode electron source according to claim 1, characterized in that: The vacuum housing (1) is made of stainless steel.

8. The single-energy X-ray tube based on a cold cathode electron source according to claim 1, characterized in that: The high-Z metal (5) is tungsten, lead or gold.

9. The single-energy X-ray tube based on a cold cathode electron source according to claim 1, characterized in that: The fluorescent material plate is made of silver, molybdenum or neodymium.

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