The extraction of ions from a radio-frequency discharge

The extraction of ions from the plasma of a gas discharge and their formation into a beam is investigated theoretically. The results are shown to be applicable to a gridded ion gun. The results are also applicable to the design of canal extraction systems, but it is shown that in this case a simpler method exists for obtaining the necessary information. The theory is compared with the results of experiments and some agreement is found for sufficiently high accelerating voltages. The discrepancy is believed to be the result of the partial neutralization of the beam by secondary electrons in the experiments.