象散电子枪

electron gun tilted electron gun axially symmetrical electron gun narrow neck electron gun shielded electron gun astigmatic multiple electron gun zone refining concentric spherical mesh grid electron gun astigmatic lens astigmatic bundle astigmatic correction tetrode electron gun Muller electron gun three-electron gun electrostatic electron gun electron-gun density multiplication glow-discharge electron gun tiled electron gun electron beam gun Pierce electron gun electron gun vacuum lock