一种场发射电子源用真空及控制系统的设计

The design of a vacuum and control system for field-emission electron source

场发射电子源稳定工作的高真空环境难以稳定、快速地获取,针对这个问题,本文设计了一种场发射电子源用真空及控制系统,该系统包括放置电子源的真空腔体、用于排气的泵组系统、烘烤单元、真空测量单元、温度测量单元及PLC控制单元。通过泵组排气快速抽取真空,并对电子源工作腔体及光学组件进行烘烤去气进一步提高系统真空度,其极限真空可达10E-7Pa,满足电子源正常工作条件。设计了上位机界面及PLC控制系统,能自动开启泵组、阀门及仪表,根据条件进行烘烤去气,实时监视各类参数并在发生异常时报警退出系统,提高了自动化程度和工作效率。

A high vacuum environment in which the field-emission electron source works stably is difficult to obtain stably and rapidly, to solve this problem, a vacuum and control system for field-emission electron source is designed which includes a vacuum chamber with electron source, a pump system, a baking unit, a vacuum measuring unit, a temperature measuring unit and a PLC control unit. Vacuum is rapidly extracted by pump group, the working chamber and optical components are baked to further improve the vacuum. The limit vacuum can reach 10E-7Pa, which meets the working conditions of the electron source. The upper computer interface and the PLC program are designed to automatically open pumps, valves and instruments, bake according to the conditions, monitor various parameters , alarm and withdrawn the system when abnormal happens, which improves the automation level and work efficiency.