频率可调太赫兹回旋振荡管互作用电路的设计与研究

根据动态核极化核磁共振成像技术对回旋振荡管的要求,设计了130 GHz回旋振荡管的注波互作用电路,基于线性理论对互作用电路进行了研究并选择了合适的工作点,分析了电路的频率调节特性。利用相对论电子回旋脉塞非线性理论对互作用系统进行了模拟和计算,优化了工作参数,计算了磁场及电子注参数对输出功率及效率的影响。最后,用粒子模拟方法进行了模拟并与非线性理论结果进行了比较,两者符合得很好。模拟结果显示,当电压为10 kV、电流为0.3 A、磁场强度由2.34 T增加到2.41 T时,输出功率由1310 W减小到230 W,对应的效率分别为43.6%和7.7%,振荡管的频率可调范围约为2.7 GHz。

Investigation and Design of a Frequency-Tunable Terahertz Gyrotron Oscillator

The beam-wave interaction system of a 130 GHz gyrotron oscillator is designed for the application of Dynamic Nuclear Polarization Enhanced Nuclear Magnetic Resonance (DNP-NMR) imaging technology. Based on the linear theory, the interaction circuit is designed, an appropriate operating point is selected and the frequency tunability of the circuit is also analyzed. Numerical simulation is carried out using the nonlinear theory of relativistic electron cyclotron maser (ECM), the operating parameters of the system are optimized and the influence of the magnetic field and electron beam parameters on the output power and efficiency are calculated, too. Finally, the particle in cell simulation is used to verify the results of nonlinear theory. The results from the two methods are in good agreement. The simulation result shows that the output power decreases from 1310 W to 230 W when the magnetic field is increased from 2.34 T to 2.41 T with the beam voltage of 10 kV and beam current of 0.3 A, the corresponding efficiency is 43.6% and 7.7%. The frequency tunability range of the gyrotron oscillator is about 2.7 GHz.