Hot Ion Beam Generation from Rare-Gas Cryogenic Targets

Energetic ions having a maximum velocity of the order of 107 cm/s were detected in the interaction of a frequency-doubled Q-switched Nd:YAG laser with rare-gas cryogenic targets at the laser intensity of 1 ×1012 W/cm2. It was observed that the angular distribution of ions strongly peaked in the target normal direction confined to a narrow range of angle following ∼cos pθ ( p=3–5). Scaling of the ion current and their velocity as a function of an incident laser energy were investigated. To analyze the effect of energetic particles from a plasma, a silicon substrate was used as a particle target. Its surface morphology revealed that micron-size solid fragments from the target dominantly affected the silicon surface.