本論文主要目的是為了設計出一支繞軸大軌跡CUSP電子槍擁有較大的速度比及較低的速度發散，以提供給400 GHz TE41第四諧波的磁旋返波振盪器( gyro-BWO )圓柱形波導管使用。
CUSP電子槍的主要特性是磁旋中心半徑為零，根據電子與波耦合參數定義可知，當磁旋中心半徑為零時，諧波數s等於模數m才有非零值。運用此特性，可降低模式競爭。
Terahertz頻率大約0.1THz ~ 10THz，介於毫米波與紅外光之間，近年來有關THz的科技蓬勃發展，但THz的波源目前還處於是一個待開發的領域，所以設計出一支電子槍以供400 GHz高次諧波的磁旋返波振盪器有其必要性。

[1] Gol’denberg, A. L., and Petelin, M. I., The formation of helical electron beams in an adiabatic gun. Radiophysics and Quantum Electronics 16, 1, pp. 106-111, January 1973.
[2] Seftor et al.1979, Caplan & Thorington 1981, Kim et al.1981, Baird & Lawson 1986, Lawson et al. 1986.
[3] Gallagher D A,Barsanti M,Scafuri F,et al.High-power cusp gun for harmonic gyro-device applications[J].IEEE Trans on Plasma Science,2000,28(3):695-699.
[4] F. Li, W. He, A.D.R. Phelps, A.W. Cross, C.R. Donaldson, and K. Ronald, The Design of a 390 GHz Gyrotron Based on a Cusp Electron Gun. Infrared, Millimeter and Terahertz Waves, 2008. IRMMW-THz 2008.
[5] A. S. Gilmour, Jr., Microwave Tubes (Artech House, Dedham,MA, 1986).
[6] W. B. Herrmannsfeldt, “EGUN Electron Optics program”, Standford Linear Accelerator Center, 1996.
[7] Avdoshin, E. G., and Gol’denberg, A. L., Experimental investigation of adiabatic electrons guns of cyclotron-resonance masers. Radiophysics and Quantum Electronics 16, 10, pp. 1241-1246, Qctober 1973.
[8] Avdoshin, E. G., Nikolaev, L. V., Platonov, I. N., and Tsimring, Sh. E., Experimental investigation of the velocity spread in helical electron beams. Radiophysics and Quantum Electronics 16, pp. 416-466, 1973.
[9] Gaponov, A. V., Flyagin, V. A., Gol’denberg, A. L., Nusinovich, G. S., Tsimring, Sh. E., Usov, V. G., and Vlasov, S. N., powerful millimeter-wave gyrotrons. Int. J. Electronics 51, 4, pp. 277-302, 1981.
[10] Tsimring, Sh. E., Synthesis of systems for generation helical electron beams, Radiophysics and Quatum Electronics, vol. 20, pp. 1550-1560, 1977.
[11] Baird, J. Mark, and Lawson, W., Magnetron injection gun (MIG) design for gyrotron applications. Int. J. Electronics 61, 6, pp. 953-967, 1986.
[12] Kyler, Carolyn and Chu, K. R., Genergation and improvement of the gyrotron electron beam in a biased cusp magnetic field. NRL Memorandum report 4401, April 23, 1981.
[13] C. P. Yuan, T. H. Chang, N. C. Chen, and Y. S. Yeh, Magnetron Injection Gun Design for Broadband Gyrotron Backward-Wave Oscillator, submitted to Physics of Plasma.
[14] 劉蕙娜，“磁控鎗( MIG )的特性研究與設計方法”，國立清華大學物理研究所，1987年。
[15] 陳錦輝，“電子槍模擬分析”，國立清華大學物理研究所，1988年。
[16] 洪培修，“Ka頻段電子光學系統-----雙陽極Pierce型電子鎗之設計”，國立清華大學物理研究所，1999年。