X-ray pinch diode composite cathode and design method thereof

Abstract

The invention relates to an X-ray pinch diode composite cathode and a design method thereof. In the invention, a cathode disc is pasted with a dielectric material which can influence the geometric configuration of an electron emission surface, regulate pinch state of an electron beam and reduce the lateral focal spot of X ray, thus the aim of reducing axial focal spot is realized, wherein the adopted dielectric material is polytetrafluoroethylene, and fish bread glue is adopted in the pasting process. The thickness of a graphite disc is 2.2mm, the outer radius of a cathode disc is 74mm, the inner radius is 8mm, and the rear surface of the cathode graphite disc is pasted with a dielectric material layer with the thickness of 1mm. The invention has the beneficial effect that X-ray axial focal spot produced by an anode bar pinch diode is obviously reduced by adopting the composite cathode under the environment with the same diode working voltage.

Description

technical field [0001] The invention relates to a compound cathode of an X-ray pinch diode and a design method thereof, belonging to high-power diode technology, in particular to a cathode design method for improving the output characteristics of an anode rod pinch diode. Background technique [0002] The anode rod pinch diode can produce high dose rate (the output X-ray dose rate at 1m directly in front of the ray source can reach ~10 6 Gy / s), small focal spot (forward direction<1mm, axial several mm), short pulse (~50ns) high-energy X-rays have important application value in pulsed X-ray flash photography. The focal spot size of the ray source is the main factor affecting the spatial resolution of imaging. The focal spot of the ray source includes a forward focal spot and an axial focal spot. It is facing the needle tip and the line of sight is consistent with the axial direction of the diode. The observed focal spot is the forward focal spot of the ray source, such as...

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Problems solved by technology

The hollow composite anode uses a small-diameter hollow aluminum rod as the anode, and a gold ball with a diameter of ~1mm is embedded at the end of the aluminum rod. Due to the low atomic number of aluminum, the bremsstrahlung interaction with electrons is weak, so the anode tip is reduced. Part of the X-ray generation efficiency, the effect of reducing the axial focal spot is obvious, but the wall thickness of the hollow aluminum rod is only tens of microns, which is difficult to process and expensive

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