小型纳秒级方波脉冲电源的研制

Design of compact nanosecond rectangle pulse power supply

采用飞行时间法测量原子氧束能谱时,要求离化源为纳秒级脉宽、能量均匀的脉冲电子束,以尽量降低离子收集器附近产生的等离子体鞘层电位对原子氧束能谱测量精度的影响。针对上述脉冲电子束的性能要求,研制了一款基于雪崩三极管Marx电路的小型方波脉冲源。首先介绍了雪崩三极管的工作特性、Marx电路的升压原理以及元器件的选取方法;然后结合脉冲形成线电压波反射原理,建立了同轴线缆充电时的电路方程;分析了方波脉冲成形机理和传输线阻抗对输出脉冲波形的影响,将同轴电缆传输线等效为分布式电感电容模拟网络,搭建了同轴电缆传输线仿真模型;设计制作了具体电路,在各级模拟网络充放电特性仿真结果的指导下,针对性地对同轴电缆传输线的姿态进行微调,改善了输出波形。实际电路产生了幅值±200～300 V、频率1～10 kHz可调、双快边沿纳秒方波脉冲。

When measuring spectrum of the atom oxygen beam with the time-of-flight method, the ionization source is required to be the electron beam with nanosecond pulse width and uniformity energy, to reduce the space potential and sheath potential influence on the accuracy of the spectrum of the atom oxygen beam measurement near the ion collector. Aiming at the property requirement of the pulse electron beam, a kind of compact rectangle pulse power supply based on avalanche transistor Marx circuit was designed. Firstly the working characteristics of avalanche, the boost principle of Marx circuit and the method to choose the item of the circuit were introduced in detail;combining the voltage wave reflecting principle of pulse forming line, this paper established the equation of the coaxial cable when charging, then analyzed the mechanism of the rectangle pulse forming and the relationship between transmission line impedance and the output pulse waveform;furthermore, this paper regarded coaxial cable transmission line as the inductive capacitance simulation network, and built coaxial cable transmission line simulation model. Real circuit was made and the output rectangle pulse waveform could be easily improved by tuning the attitude of coaxial cable transmission line, according to result of the every state charging characteristic of simulation network. Finally, the circuit produced a stable nanosecond rectangle pulse with dual quick edge, adjustable voltage amplitude adjustable from ±200 V to 300 V, and frequency adjustable from1 to 10 kHz.