Low pressure oscillatory discharge regime of a pulsed duopigatron source

One of the most important goals in the ion source technology is to increase the ionization efficiency in order to reduce the neutral gas flux introduced in the vacuum system. The paper presents some aspects of the low gas flux regime of hydrogen plasma generation in a pulsed duopigatron ion source. Despite the oscillatory behaviour of the discharge at low gas pressure (6 x 10-3 mbar), short pulses of about 20 ms duration and 20 A discharge current can be selected and used to produce ion beams with the same intensities as at higher pressure ( ≅ 5·10-3). This low pressure/short pulse regime of the investigated duopigatron ion source can be applied in electrically floated ion-beam injectors taking into account the significant reduction in vacuum system dimensions. (author)