针对800 kA,0.1 Hz重复频率LTD模块设计新的多间隙气体开关，要求在较高工作电压(高于±80 kV)和较低工作系数(低于70%)下抖动优于2 ns。通过电场仿真分析，优化了气体开关电极形状。串联间隙从4个增加为6个，总间隙长度为36 mm，充电±100 kV、触发100 kV时触发间隙场畸变系数为3.98。实验表明，新气体开关静态自击穿性能稳定，动态触发性能可靠。充电±90 kV、工作系数60%时击穿延时40.1 ns，抖动1.3 ns。

A multi-gap gas switch was designed for the LTD stage to replace the switch which has a high self-breakdown probability at the voltage over ±80 kV. The shape of the electrode was designed to be circularity due to the electric field simulation of the electrode. The total length of the switch’s gaps was increased from 28 mm to 36 mm while the number of the gaps increased from 4 to 6. The distortion ratio of electric field was 3.98 when the switch was charged to ±100 kV and triggered by 100 kV. The self-breakdown voltage testing has been conducted and the relation between self-breakdown voltage and gas pressure was obtained when the switch was filled with dry-air. As the pressure changed from 0.10 MPa to 0.20 MPa, the self-breakdown voltage increased from 103 kV to 194 kV. The experimental results of triggering feature show that the new switch had 40.1 ns delay with 1.3 ns jitter operating at ±90 kV which was 60% of the self-breakdown voltage.