Study of Isotope Effect on H-/D- Volume Production in Low-Pressure H2 /D2 Plasmas Using VUV Emission.

Isotope effect on H[sup -]/D[sup -] volume production is studied by using VUV emission. Under the same discharge conditions, VUV emission (corresponding to production of vibrationally excited molecules) in hydrogen plasmas is higher than that in deuterium plasma. Within the present experimental conditions, H[sup -] current is higher than D[sup -] current, although, considering the factor √2, D[sup -] ion density in the source is nearly equal to H[sup -] ion density under low discharge power. Effect of argon additive in negative ion sources is also discussed briefly. [ABSTRACT FROM AUTHOR]