DNP-NMR用263 GHz回旋振荡管高频系统的研究

Circuit Design of 263 GHz Gyrotron Oscillator for Dynamic Nuclear Polarization Enhanced Nuclear Magnetic Resonance

根据动态核极化核磁共振(DNP-NMR)发展需要,对应用于400 MHz DNP-NMR的263 GHz回旋振荡管高频系统进行研究,通过非线性理论计算程序对其进行分析,给出了工作模式为TE03的高频系统的设计参数。并通过粒子模拟(PIC)软件进行注波互作用计算,结果表明,在工作电压10 kV,注电流0.2 A,电子注速度比为2.0时,设计的高频系统输出功率为460.2 W,效率达到23.1%,约1 GHz的调频率范围,可满足263 GHz整管参数设计要求,从而为DNP-NMR用回旋振荡管的研制打下技术基础。

Here,we addressed the design of TE03 mode interaction cavity,comprising three-section resonant cavity and used as 263 GHz gyrotron oscillator of 400 MHz dynamic nuclear polarization enhanced nuclear magnetic resonance（ DNP-NMR）. First,the 263 GHz gyrotron oscillator was analyzed by linear/nonlinear theories of gyrotron for design optimization of the interaction structure. Next,the beam-wave interaction in the newly-designed cavity was numerically simulated with particle-in-cell（ PIC） code. The simulated results show that the novel circuit is capable of meeting the requirements of 263 GHz gyrotron. To be specific,operating at 10 kV,0. 2 A and 263. 13 GHz,the electron beam with a velocity ratio of 2. 0 generates a stable output power of 460. 2 W and displays an efficiency of 23. 1%; moreover,the smooth frequency tuning range roughly covers 1 GHz. We suggest that the newly-designed circuit be of some technological interest in gyrotron applications to DNP-NMR.