Joye Colin D, Shapiro Michael A, Sirigiri Jagadishwar R, Temkin Richard J
Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
IEEE Trans Electron Devices. 2009 May 1;56(5):818-827. doi: 10.1109/TED.2009.2015802.
The theory, design, and experimental results of a wideband 140-GHz 1-kW pulsed gyro-traveling-wave amplifier (gyro-TWA) are presented. The gyro-TWA operates in the HE(06) mode of an overmoded quasi-optical waveguide using a gyrating electron beam. The electromagnetic theory, interaction theory, design processes, and experimental procedures are described in detail. At 37.7 kV and a 2.7-A beam current, the experiment has produced over 820 W of peak power with a -3-dB bandwidth of 0.8 GHz and a linear gain of 34 dB at 34.7 kV. In addition, the amplifier produced a -3-dB bandwidth of over 1.5 GHz (1.1%) with a peak power of 570 W from a 38.5-kV 2.5-A electron beam. The electron beam is estimated to have a pitch factor of 0.55-0.6, a radius of 1.9 mm, and a calculated perpendicular momentum spread of approximately 9%. The gyro-amplifier was nominally operated at a pulselength of 2 μs but was tested to amplify pulses as short as 4 ns with no noticeable pulse broadening. Internal reflections in the amplifier were identified using these short pulses by time-domain reflectometry. The demonstrated performance of this amplifier shows that it can be applied to dynamic nuclear polarization and electron paramagnetic resonance spectroscopy.
介绍了一种宽带140GHz、1kW脉冲回旋行波放大器（gyro-TWA）的理论、设计和实验结果。该回旋行波放大器在过模准光导波的HE(06)模式下运行，使用回旋电子束。详细描述了电磁理论、相互作用理论、设计过程和实验步骤。在37.7kV和2.7A的束流条件下，实验产生了超过820W的峰值功率，-3dB带宽为0.8GHz，在34.7kV时线性增益为34dB。此外，该放大器在38.5kV、2.5A的电子束条件下，产生了超过1.5GHz（1.1%）的-3dB带宽，峰值功率为570W。估计电子束的螺距因子为0.55-0.6，半径为1.9mm，计算得到的垂直动量展宽约为9%。该回旋放大器标称脉冲长度为2μs，但测试了其对短至4ns的脉冲进行放大，且没有明显的脉冲展宽。通过时域反射计使用这些短脉冲识别了放大器内部的反射。该放大器展示的性能表明它可应用于动态核极化和电子顺磁共振光谱学。
