Ion extraction characteristics from laser induced plasma by radio-frequency resonant method

In order to raise ion extraction efficiency in atomic vapor laser isotope separation, a new method using a radio-frequency (RF) electric field has been developed. The RF is applied to the plasma which is sandwiched between parallel electrodes in a low magnetic field (5 mT). This excites a plasma-sheath resonance. The ion extraction characteristics were studied by using the photo-ionized plasma, having the density and electron temperature of 3 x 1016 m-3 and 0.1 eV, respectively. The plasma-sheath resonance occurred at 12 MHz at which the ion extraction time became a minimum. To obtain the same extraction time as when applying a -3kV DC voltage in the conventional electrostatic method, this method needed only a 400 Vpp RF voltage with a -1kV DC voltage. (author)