Second harmonic operation at 460 GHz and broadband continuous frequency tuning of a gyrotron oscillator
Second harmonic operation at 460 GHz and broadband continuous frequency tuning of a gyrotron oscillator
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DOI：
10.1109/ted.2005.845818
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发表时间：
2005-05-01
影响因子：
3.1
通讯作者：
Temkin, RJ
中科院分区：
文献类型：
--
作者：
Hornstein, MK;Bajaj, VS;Temkin, RJ
我们报告的短脉冲操作的460 GHz的回旋振荡器在基本（近230 GHz）和二次谐波（近460 GHz）的电子回旋共振。在微秒，脉冲长度制度与13 kV的束电压和110 mA的束电流的操作期间，该仪器在两个二次谐波模式下产生几瓦的功率，TE 2，6，1在456.15 GHz和TE 0，6，1在458.56 GHz。在输出功率高达70 W时，观察到基模工作，包括237.91 GHz的TE 0，3，1模和233.15 GHz的TE 2，3，1模。此外，我们证明了宽带连续频率调谐的振荡器的基本模式在超过2 GHz的范围内，通过单独的磁场的变化。我们解释这些结果的谐振器的高阶轴向模式之间的平滑过渡。460千兆赫回旋管目前正在处理连续工作，在那里它将作为一个微波源的灵敏度增强的核磁共振（动态核极化）研究在16 T（700兆赫H-1），场强是两倍以上，已与以前的技术。
We report the short-pulse operation of a 460 GHz gyrotron oscillator both at the fundamental (near 230 GHz) and second harmonic (near 460 GHz) of electron cyclotron resonance. During operation in a microsecond, pulse length regime with 13-kV beam voltage and 110-mA beam current, the instrument generates several watts of power in two second harmonic modes, the TE2,6,1 at 456.15 GHz and the TE0,6,1 at 458.56 GHz. Operation in the fundamental modes, including the TE0,3,1 mode at 237.91 GHz and the TE2,3,1 at 233.15 GHz, is observed at, output powers up to 70 W. Further, we demonstrate broadband continuous frequency tuning of the fundamental modes of the oscillator over a range of more than 2 GHz through variation of the magnetic field alone. We interpret these results in terms of smooth transitions between higher order axial modes of the resonator. The 460 GHz gyrotron is currently being processed for continuous duty operation, where it will serve as a microwave source for sensitivity-enhanced nuclear magnetic resonance (dynamic nuclear polarization) studies at 16 T (700 MHz H-1), a field strength which is two-fold higher than has been accessible with previous technology.