Grid-control cold cathode X-ray tube

Abstract

The invention relates to a grid-control cold cathode X-ray tube which comprises a vacuum cavity, an anode assembly, a grid-control electrode and a cathode assembly. The anode assembly comprises an anode target, an anode metal hood and an anode connection pillar. The anode target, the anode metal hood and the cathode assembly are packaged in the vacuum cavity. The anode target is embedded in the anode metal hood and used for producing X rays. The normal line of a plane of the anode target is connected with an anode and a cathode to form an inclination angle which is (12+ / -1) degrees. The cathode assembly comprises a cathode substrate and a cathode material which is arranged on the cathode substrate. The cathode hood serving as the grid-control electrode covers a cathode installation part which comprises a cathode lead and a grid lead. The cathode hood is made of metal. A hole is formed in the cathode hood and located in the connection line of the cathode substrate and the anode target. High voltage is led in through the anode connection pillar. The cathode hood serving as the grid-control electrode is connected with the grid lead. The cathode substrate is connected with the cathode lead. Voltage is exerted between two electrodes led out from the grid lead and the cathode lead.

Description

technical field [0001] The invention relates to an X-ray tube, in particular to a gate-controlled cold-cathode X-ray tube and its assembly method. technical background [0002] An X-ray tube is a device that allows the controlled emission of X-rays. They are used in various systems, for example, X-ray imaging technology in medical, industrial and security fields, spectral analysis (X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy), X-ray diffraction analysis, etc. The principle of generating X-rays in a ray tube is to use high-energy electrons (tens of thousands of electron volts) to bombard a metal target. The interaction between these electrons and the target is multiplied until X-rays are emitted. The X-ray intensity is directly proportional to the electron flow on the target material. The penetration of X-rays is directly proportional to the applied voltage on the target material. The emission area of ​​X-rays is determined by the range of electron b...

AI Technical Summary

Problems solved by technology

Through patent retrieval, there are currently 8 patents for X-ray tubes using cold cathodes as electron sources in China: 1. Patent 03127012.3, "A New Type of Field Emission Medical Miniature X-ray Tube". The X-ray tube involved in this patent has no Electron beam converging function makes it difficult to realize small focus; 2. Patents CN201378580Y, CN201378579Y, CN101521135B, CN101494149A and CN101101848B, "Grid-controlled carbon nano cathode field emission X-ray tube, the ray tube assembly process involved in this patent is complicated and the cost is high; 3 , patent CN101494150A, the ray tube designed by this patent, the grid type is a planar grid, the field emission material used in this structure is zinc oxide, and the emission performance is poor; 4, the patent CN1553473A, the anode voltage of this patent is too low, and the ray penetration is poor

[0005] Judging from the existing technology, the current gate-controllable X-ray tubes have certain limitations, mainly in the following aspects: (1) Complex assembly process; (2) No electron beam convergence; (3) Grid control intercepted electrons etc.

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