GENERATION OF MULTIPLY-CHARGED SILICON AND GERMANIUM IONS BY EXCIMER-LASER PULSES

Plasma bursts were produced by focusing excimer-laser (XeCl, 308 nm) p ulses on Ge and Si targets. At moderate laser fluences (approximately 30 MW/cm2) high-intensity Ge3+ and Si3+ ion pulses were extracted from the laser-produced plasma. A peculiar electrical circuit allows a sel f-bunching of the beam. By time-of-flight method, the currents produce d by the ions of different charge number were measured. Peak currents of 620 mA and 800 mA were recorded for Ge3+ and Si3+ ions, respectivel y, with an extraction voltage of only 400 V.