A high-yield ion source for producing beams of H+, H+3, He+, Ne+, Ar+, Li+, K+, Na+, and Cd+

A high-yield radio-frequency ion source is described in which the ionization efficiency has been considerably enhanced by arranging for the radio-frequency oscillator to excite the lowest-order (m=0) helicon wave in the plasma. It has been used to produce intense beams of H+, H+3, He+, Ne+, Ar+, Li+, K+, Na+, and Cd+. A proton beam of up to 10 mA H+ is attainable, with a proton fraction in excess of 96%, using only 300 W of excitation power.