Small Ion Driven VUV/UV Light Sources for Laboratory Applications

摘要

Inertial electrostatic confinement (IEC) devices offer a unique method to generate energetic ions for excitation of rare gas and rare gas halide excimers. A unique feature for this approach is that it allows small sized units with the ion source and excimer medium contained in vessels of order 30-cm radius. The IEC operates by applying a high negative voltage (up to -100 kV) on a spherical mesh grid (cathode) located in the center of a grounded grid (anode), all within a spherical vacuum vessel. A plasma discharge is created between the grids. The cathode extracts ions from the discharge and accelerates them towards the center of the device. Large ion background gas collision densities are created in the center region and along the ion beam paths, creating intense light emission. An alternate approach discussed here allow lower operating pressures and reduced ion thermalization, giving improved emission efficiencies, uses an external RF ion generator to separate the injected species from the mixture. The injector increases the device size, but a compact RF source has been developed which involves injector diameters of only ～6 cm by 30- cm length. Designs for such devices and their operation will be described.