Asian Journal of Physics Vol 32, Nos 9 – 12 (2023) 573-580

Design and development of a sheet-beam electron gun with large current for a THz traveling-wave tube

Xuyuan Chen1, Lin Xu1, Xiao Sun1, Shengkun Jiang1, Yasong Fan2, Guang Yang2, Zhifang Lyu1, Tao Tang1, and Zhaoyun Duan1
1National Key Laboratory of Science and Technology on Vacuum Electronics in Chengdu, School of Electronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), 611731 Chengdu, China
2Nanjing Sanle Group Co., Ltd,211800 Nanjing, China
Dedicated to Prof B N Basu

In this paper, the design, development and experimental investigation on a sheet-beam electron gun with large current for a THz traveling-wave tube (TWT), which can operate typically at 0.22 THz frequency, is reported. The cylindrical cathode is made of scandate, and the pencil electron beam is compressed into a sheet beam by an elliptical focusing electrode. The maximum beam current of 123.4 mA was predicted with the emission current density of 24.56 A/cm2 in simulation with 22 kV beam voltage. In the sheet-beam electron gun, the distance between the emission surface of the cathode and the beam-waist was found as 11 mm, and the wide edge and narrow edge of the beam waist cross-section are 0.38 mm and 0.1 mm, respectively. The components of the sheet-beam electron gun were fabricated and subsequently assembled. Its assembly errors were detected. The simulation predicts that the beam transportation in the sheet-beam electron gun under the condition of assembly errors exceeds 96%. The study also includes the experimental characterization of the cathode emission of the gun. The preliminary experimental results of the sheet-beam electron gun indicate that the beam current of 80 mA with the beam voltage of 22 kV was obtained from the proposed design. The experiment remained useful towards development of a 0.22 THz futuristic TWT. © Anita Publications. All rights reserved.
Keywords: Sheet beam, Electron gun, Terahertz TWT.

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Method: Single- anonymous; Screened for Plagiarism? Yes
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