D(-)/H(-) negative ion production versus plasma parameters in a volume negative ion source.
Pure volume production of D(-) negative ions is studied in rectangular negative ion source equipped with an external magnetic filter (MF). Plasma parameters (n(e) and T(e)) in D(2) plasmas are varied mainly in the downstream region by changing the magnetic field intensity of the MF (i.e., B(MF)). Production and control of D(2) plasma is nearly the same as that of H(2) plasmas, although the values of n(e) and T(e) in D(2) plasma are slightly higher than that of H(2) plasmas in both the source and the extraction regions. On D(-)/H(-) production, however, it appears some different points. By varying the B(MF), H(-) production in the extraction region is remarkably changed corresponding to the variation of n(e) and T(e) in the extraction region. On the other hand, D(-) production is not so varied under the same discharge conditions in H(2) plasmas. This difference in D(-) production is not well explained only variation of n(e) and T(e) in D(2) plasmas. Optimum B(MF) and gas pressure for D(-) production is slightly higher than that for H(-) production.
Mori
Shigefumi
S
Graduate School of Science and Engineering, Yamaguchi University, Ube, Japan.
Fukumasa
Osamu
O