Amplification of Picosecond Pulses in a 140-GHz Gyrotron-Traveling Wave Tube
Author(s)Temkin, Richard J.; Nanni, Emilio Alessandro; Shapiro, Michael; Sirigiri, Jagadishwar R.; Kim, H. J.; Woskov, Paul P.; ... Show more Show less
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An experimental study of picosecond pulse amplification in a gyrotron-traveling wave tube (gyro-TWT) has been carried out. The gyro-TWT operates with 30 dB of small signal gain near 140 GHz in the HE06 mode of a confocal waveguide. Picosecond pulses show broadening and transit time delay due to two distinct effects: the frequency dependence of the group velocity near cutoff and gain narrowing by the finite gain bandwidth of 1.2 GHz. Experimental results taken over a wide range of parameters show good agreement with a theoretical model in the small signal gain regime. These results show that in order to limit the pulse broadening effect in gyrotron amplifiers, it is crucial to both choose an operating frequency at least several percent above the cutoff of the waveguide circuit and operate at the center of the gain spectrum with sufficient gain bandwidth.
DepartmentMassachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Plasma Science and Fusion Center
Physical Review Letters
American Physical Society
Kim, H. J. et al. “Amplification of Picosecond Pulses in a 140-GHz Gyrotron-Traveling Wave Tube.” Physical Review Letters 105.13 (2010): 135101. © 2010 The American Physical Society.
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