X-ray bulb tube cathode electron enhancement device

An intensifying device and X-ray technology, which is applied in the field of X-ray tubes, can solve the problems of reducing filament life, breakdown, and rapid evaporation of tungsten metal, and achieve the effects of prolonging life, avoiding switching, and reducing the burden of electron emission

Pending Publication Date: 2021-09-24
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in order to provide the strong electric field required to achieve "switching" and "cutting off", the grid must be placed within 5mm of the filament, and the voltage on it must be as high as kilovolts (-10kV ~ 10kV). The electric field strength between them is likely to exceed the dielectric strength of the vacuum, resulting in the occurrence of electrical breakdown (commonly known as the "sparking" problem)
On the other hand, in order to emit a sufficient amount of thermal electrons, the temperature of the filament must be very high, which will cause the rapid evaporation of metal tungsten, which greatly reduces the life of the filament

Method used

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  • X-ray bulb tube cathode electron enhancement device
  • X-ray bulb tube cathode electron enhancement device
  • X-ray bulb tube cathode electron enhancement device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] like figure 1 As shown, the X-ray tube cathode electron enhancement device of this embodiment includes a grounding terminal 1, an AC power supply 3, a cathode 4, and an anode 7. The grounding terminal 1 is a -70kV high-voltage ground, and the AC power supply 3 is a 5-12V low-voltage power supply. , one end of the AC power supply 3 is connected to the ground terminal 1 , both ends of the cathode 4 are connected to the AC power supply 3 , and the anode 7 is arranged opposite to the cathode 4 . The film window 8 is arranged between the cathode 4 and the anode 7, and the two sides of the film window 8 are provided with electrode pairs 9, and the electrode pairs 9 are powered by the capacitor pair 2, and the film window 8, the electrode pair 9, and the capacitor pair 2 form a secondary electron emission source. The capacitor pair 2 includes two capacitors connected in series, namely a first capacitor 21 and a second capacitor 22 , and one end of the second capacitor 22 is ...

Embodiment 2

[0035] like figure 2 As shown, the basic composition of the X-ray tube cathode electron enhancement device of this embodiment is the same as that of Embodiment 1, the difference is that this embodiment also includes a grid 5 and a grid capacitor 13, and the grid 5 is arranged on the thin film window 8 On both sides, the gate 5 is connected to a gate capacitor 13 which is connected to a first capacitor 21 . In this embodiment, the grid 5 does not need to have the function of quickly "switching" and "cutting off" X-ray emission, but only needs to realize the control of the focus size and position of the secondary electron beam 12 . The electric field intensity required for the focus control of the secondary electron beam 12 is far lower than the dielectric strength of vacuum, and no electrical breakdown will occur between the grid 5 and the film window 8. Therefore, the voltage of the grid 5 does not need to be very high. The grid 5 also does not need to be placed very close t...

Embodiment 3

[0039] like image 3 As shown, the basic composition of the X-ray tube cathode electron intensifier device of this embodiment is the same as that of Embodiment 1, except that the secondary electron emission source composed of film window 8, electrode pair 9 and capacitor pair 2 in this embodiment Step-by-step multiplication is set, and the second end of the capacitance pair of the secondary electron emission source of the subsequent stage is connected to the first end of the capacitance pair of the secondary electron emission source of the previous stage. In this embodiment, the electrons emitted from the cathode 4 are accelerated and multiplied step by step and then bombard the anode 7 to emit X-rays. The multi-level electron-enhanced cascaded cathode structure can further reduce the electron emission burden of the filament and better extend the life of the filament.

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Abstract

The invention discloses an X-ray bulb tube cathode electron enhancement device, and relates to the technical field of X-ray bulb tubes, the X-ray bulb tube cathode electron enhancement device comprises a cathode, an anode, an AC power supply, a film window, an electrode pair and a voltage element, one end of the AC power supply is grounded, two ends of the cathode are connected with the AC power supply, and the anode is arranged opposite to the cathode.The device also comprises a film window, an electrode pair and a voltage element, and the film window is arranged between the anode and the cathode; each electrode pair comprises two electrodes, the two electrodes of each electrode pair are arranged on the two sides of the film window, and the two electrodes of each electrode pair are connected to a voltage element; and the film window, the electrode pair and the voltage element form a secondary electron emission source. The service life of the cathode filament can be prolonged, and meanwhile electric breakdown is avoided when X-ray emission is rapidly switched and cut off.

Description

technical field [0001] The invention relates to the technical field of X-ray tubes, in particular to an X-ray tube cathode electron enhancement device. Background technique [0002] The cathode assembly of a conventional X-ray tube usually adopts a hot cathode, and its specific structure is as attached Figure 4 shown. One end of the filament as the cathode is connected to the high voltage ground of -70kV, and the other end is connected to the AC power supply of 5-12V. The filament is heated by power supply so that its temperature reaches about 1900-2600°C, thereby emitting electrons. A high voltage of 70kV is applied to the anode, and a high voltage electric field is formed between the anode and the cathode. Electrons emitted from the cathode bombard the anode under the acceleration of a high-voltage electric field to generate X-rays. Grids are installed on both sides of the filament to control the size and position of the focal point of the electron beam, and to quickly...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01J35/06
CPCH01J35/065
Inventor 赵俊林泽帆孙建奇张溥明张曦邹昀
Owner SHANGHAI JIAO TONG UNIV
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