Experimental research on the effect of cesium injection into high power negative ion source

Cesium injection can significantly reduce the surface work function of plasma grid of Radio Frequency negative ion source, which is an effective means to promote the surface generation and improve the yield of H− ions.This study aims to find the impact of the temperature of PG and the cesium injection velocity on the yield of H− ions under cesium injection conditions. [Methods] Based on the experimental platform of high power Radio Frequency negative ion source, this paper takes the mechanism of H− ions surface generation and cesium injection as theoretical basis, and takes the current of H− ions, electron current and the relative strength of cesium characteristic spectral line as numerical basis.

Under current experimental conditions, cesium injection has the best effect when temperature of PG is 180~200 ℃, and the H− ions conversion rate reached dynamic equilibrium after about 162 min, when the temperature of cesium injection is 250 ℃/270 ℃. The experimental results show that cesium injection can effectively increase the H− ions yield.