基于亥姆霍兹线圈的电子束偏转扫描技术研究

Research of Electron Beam Deflection Scanning Coil Based on Helmholtz Coil

针对电子束偏转扫描频率低以及扫描线圈磁场不均匀的问题,研究了电子束在磁场中的运动原理,设计了基于亥姆霍兹线圈的电子束偏转扫描线圈,并研究了相应的驱动电路。由电子枪的结构尺寸及亥姆霍兹线圈的基本原理设计了扫描线圈,由电子枪加速电压、工作距离及所需偏转范围确定了所需磁场强度,并进一步计算了安匝数。设计了基于PID控制的高频扫描驱动电路。结果表明,所设计的电子束偏转扫描线圈的磁场强度均匀性高,其驱动电路性能稳定,流过扫描线圈3A电流高达30kHz。

Aiming at the problem of low scanning frequency of electron beam deflection and non-uniform magnetic field of scanning coil,the principle of electron beam motion in magnetic field is studied.The electron beam deflection scanning coil based on Helmholtz coil is designed and the corresponding driving circuit is studied.The scanning coil is designed by the structural dimensions of the electron gun and the basic principle of the Helmholtz coil.The required magnetic field strength is determined by the electron gun acceleration voltage,the working distance and the required deflection range,and the number of ampere turns is further calculated.A high frequency scanning drive circuit based on PID control is designed.The results show that the designed electron beam deflection scanning coil has high magnetic field intensity uniformity,and its driving circuit performance is stable,and the current flowing through the scanning coil 3A is as high as 30kHz.