High-sensitivity k-na-cs-sb reflective multi-alkali photocathode and preparation method and system thereof

Abstract

The invention belongs to the technical field of photomultiplier tubes, in particular relates to a photocathode, and discloses a high-sensitivity K-Na-Cs-Sb reflective multi-alkali photocathode and its preparation method and system. The alkali source component includes three alkali sources, respectively K source, Na source and Cs source; the alkali source component is connected to the exhaust table through the tailpipe to obtain ultra-high vacuum; the side window photomultiplier tube includes a glass shell, a cathode and multiple dynodes, and the cathode and multiple dynodes are constructed as A metal sheet with a certain radian, the inner surface of which is coated with a metal antimony layer; the side window photomultiplier tube is connected to the alkali source component through the exhaust tail pipe; the corresponding alkali source is applied with current to make it self-heating, releasing alkali metal vapor and antimony layer reaction to form a multi-alkali cathode structure. Among them, by monitoring the changes of leakage current and photocurrent, and monitoring the introduction process of K, Na, and Cs, the introduction of K, Na, and Cs can be precisely controlled, and the cathode sensitivity bias caused by too much or too little introduction of K, Na, and Cs can be avoided. low problem.

Description

technical field [0001] The invention belongs to the technical field of photocathode, and in particular relates to a high-sensitivity K-Na-Cs-Sb reflective multi-alkali photocathode used for a side window photomultiplier tube and a preparation method thereof. Background technique [0002] A photocathode, especially a photocathode used in a vacuum optoelectronic device such as a photomultiplier tube, is a device for capturing photons incident from the outside and exciting photoelectrons based on the external photoelectric effect. In vacuum photoelectric devices such as photomultiplier tubes, the conversion of radiation signals of different wavelengths into electrical signals is achieved by photocathode. Commonly used photocathodes mainly include double-alkali cathodes and multi-alkali cathodes, which are used in the same type of whole tube. [0003] Reflective multi-alkali photocathode is a photoemissive material often used in side window photomultiplier tubes, which can conv...

AI Technical Summary

Problems solved by technology

Therefore, in the experimental stage, we realized the control of the three stages of K, Na, and Cs by monitoring the photocurrent and reflectivity to control the evaporation of the film layer, but in the mass production process, we found that due to the above photocurrent Extremely small and inconspicuous changes, especially in the process of introducing Cs and K, the photocurrent is extremely small, and the process of introducing Na is due to the slow reaction, which makes it difficult to pass the photocurrent to reflective multi-alkali cathode K in the mass production process. , Na, Cs activation process is accurately monitored, and even in some stages of activation, the photocurrent monitoring will be completely ineffective, and the monitoring effect cannot be achieved

This leads to the use of photoelectric monitoring cathodes with low sensitivity or even no sensitivity

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