Development of a double plasma type negative ion source

We have newly designed a double plasma type negative ion source, where energy distribution of fast electrons is well controlled by changing potential difference between two chambers. With the use of this source, pure H- volume production is studied experimentally. In particular, the effect of fast electrons on H- production (i.e., energy dependence of H- production) is discussed, and preliminary results support qualitatively the two-step process of H- production