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Field emission X ray tube with light-grid compound control

A technology of field emission and composite control, which is applied in the direction of huge current X-ray tubes, X-ray tube electrodes, X-ray tube components, etc., and can solve the problems of out-of-control emission electrons, high pulse emission frequency, grid heating, etc. , to improve performance and reliability, reduce system cost, and improve reliability

Active Publication Date: 2012-02-01
广州市昊志影像科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The grids in the existing grid-controlled X-ray tubes will intercept electrons, that is, some electrons will bombard the grids, causing the grids to heat up, deform or even burn out, and generate secondary electron emission, resulting in uncontrolled emission of electrons, The X-ray tube will be scrapped in a short time; 2) Since the current grid control methods all require pulse voltage to be applied to the grid to obtain pulse emission and high pulse emission frequency
This requires an additional high-quality ultra-high voltage pulse power supply, especially in X-ray tubes, the cathode terminal is negative ultra-high voltage, and the pulse voltage applied to the grid must be superimposed on the ultra-high voltage, so the grid high-speed ultra-high voltage pulse can be realized It is very difficult to implement voltage control, and the reliability is poor; 3) In the X-ray tube, according to different requirements, the emission current needs to be changed
However, in order to achieve current control in the existing field emission X-ray tubes, the ultra-high pulse voltage applied to the grid must be adjusted. The accuracy and stability of the grid high voltage will directly affect the emission current, and the ultra-high voltage pulse high voltage Accuracy and stability are very difficult to achieve
Therefore, it is very difficult to precisely control the current of the currently reported gated X-ray tubes

Method used

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  • Field emission X ray tube with light-grid compound control
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Experimental program
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Effect test

Embodiment 1

[0045] Catalyst arrays were prepared on silicon substrates of 11 mm × 11 mm, and carbon nanotube arrays with microbeam diameters of 2 μm were prepared by microwave plasma chemical vapor deposition, and the effective growth area was 5 mm 5 mm. The prepared samples are used in the subsequent assembly of the cathode assembly.

[0046] Using a hexagonal grid structure, as attached Figure 6 As shown in b, the distance between the grid 41 and the self-converging electrode 422 is set to 180 μm, and the height of the self-converging electrode 422 is set to 20 μm. The emission trajectory of electrons is simulated by electromagnetic particle simulation software, and the electron emission trajectory is obtained in the emission state as follows: Figure 9 As shown in a, from the simulation data results, the electrons are not intercepted at the grid, and the electron beam convergence performance is good. Similarly, if there is no self-converging electrode 422, the simulation results sho...

Embodiment 2

[0048] The difference between this embodiment and Embodiment 1 is that a quadrilateral structure grid is used, as shown in the attached Figure 6 As shown in a, the height of the self-converging electrode 422 is set to 20 μm, the side length of the grid is 100 μm, and the distance between the cathode and the grid is 100 μm. The emission trajectory of electrons is simulated by electromagnetic particle simulation software, and the electron emission trajectory is obtained in the emission state as follows: Figure 10 As shown in a, from the results of the data, electrons are not intercepted at the gate. Similarly, if there is no self-converging electrode, the simulation results show that a large number of electrons hit the grid 41 and are intercepted by the grid 41, and are divergent, as Figure 10 as shown in b.

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Abstract

The invention discloses a field emission X ray tube with light-grid compound control, and the field emission X ray tube comprises a vacuum container, an anode, an anode target, a cathode assembly, a cathode supporting seat and a cathode head, wherein the cathode assembly is fixed on the cathode supporting seat; the cathode supporting seat is fixed on the cathode head; the cathode head is in vacuum sealing connection with the vacuum container by virtue of an insulating supporting seat; the cathode assembly comprises a field emission cathode, a self-convergent electrode, a grid mesh, a ceramic insulator, a high-voltage-resistance transistor and a light-emitting diode; the field emission cathode is mounted on the cathode supporting seat; a ceramic insulating column is mounted on the cathode supporting seat and is positioned at the outer side of the cathode; the grid mesh is mounted on the ceramic insulating column; the high-voltage-resistance transistor is mounted on the cathode supporting seat; and the light-emitting diode is mounted on the side wall of the cathode supporting seat. A grid electrode of the field emission X ray tube cannot intercept and capture electrons, also cannot be bombarded by the electrons to cause heating deformation and burnout, furthermore, avoids the use of an ultra-high-voltage pulse voltage, greatly improves the reliability of the field emission X raytube and decreases system cost.

Description

technical field [0001] The invention relates to a field emission X-ray tube, in particular to a field emission X-ray tube which is compound-controlled by a photoelectric tube, a transistor and a grid. Background technique [0002] At present, X-rays have been widely used in production, life and scientific research activities such as medical testing, industrial non-destructive testing and material characterization. X-ray tube is the core component of X-ray imaging, testing and CT systems, which directly determines the overall performance of the imaging system. Existing X-ray tubes mainly use hot cathodes to emit electron beams, which are accelerated to bombard anode targets to generate high-energy X-rays. Now because the hot cathode usually needs to heat the cathode to about 800-1600°C to work normally, the result is: 1) the power consumption of the device is increased, and the device temperature is high; 2) the active material of the cathode is continuously evaporated durin...

Claims

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Application Information

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IPC IPC(8): H01J35/02H01J35/04H01J35/14H01J35/22
Inventor 陈泽祥任俊胡添勇
Owner 广州市昊志影像科技有限公司