Speaker
Description
A new microwave driven Cs-free H$^{-}$ ion source was designed at Peking University for the mechanism research of H$^{-}$ source. To understand the influence of liner material to the performance of this ion source, a series of experiments with different materials of liners of Ta, Au, Be, Al, Cu have been carried out recently. In our experiment, H$^{-}$ beam was extracted with negative voltage of 35 kV and ion species of H$^{+}$, H$^{2+}$ and H$^{3+}$ were extracted from plasma with positive voltage of 35 kV. All of these experiments were performed in vacuum pressure of 7×10$^{-3}$ Pa with RF power of 2800 W (100 Hz/0.5 ms). The experiment results show that the liners of Ta, Ni, Au are much better than Al, Cu. This phenomenon will be explained based on the difference of second electron emission coefficient and work function of each material. The results will benefit us to better understand the physical principle of H$^{-}$ source and help us to figure out a better performance. Details will be presented in the article.
