Emittance and divergence evolution of ion beams extracted from high flux laser plasma

Summary form only given, as follows. Summary form only given. In order to produce high flux heavy ions, a laser ion source with short drift distance has been developed. A copper rod was used as the laser target, thus the source plasma, and a frequency doubled Nd-YAG laser was focused on it with 300 mm focal length. The distance from laser target to the acceleration gap was less than 12mm and the acceleration gap was 20 mm. The evolution of beam emittance and its divergence was measured with a pepper-pot type beam monitor, as a function of laser power density and the timing of extraction voltage. The beam images were amplified with a MCP plate gated with 300 nsec cable pulser. The characteristics of the temporal evolution of beam emittance and divergence were well correlated with the behavior of the ion emitting surface. At the optimum condition, it can produce high flux ion beams of 100mA/cm/sup 2/ level with emittance less than 0.5 /spl pi/ min mrad and flat-top waveform. Prospects of the potentiality and the quality of the ion beams are discussed together with the discussion of transient behavior of the ion emitting surface in the acceleration gap.