An Innovative high-power constant-current pulsed-arc power-supply for a high-density pulsed-arc-plasma ion-source using a LaB-filament

Ueno, Akira  ; Oguri, Hidetomo  ; Ikegami, Kiyoshi*; Namekawa, Yuya; Okoshi, Kiyonori ; Tokuchi, Akira*

A constant-current pulsed-arc-power-supply (CCPAPS) is indispensable to operate a high-density pulsed-arc-plasma ion-source using a lanthanum hexaboride filament stably, since its emission current dependence on temperature is rather steep. The deviation of arc-current is positively feed-backed if power-supply is constant-voltage controlled. Furthermore, it shortens the rising time of arc-current by naturally produced overshoot voltage. Although a CCPAPS was developed using an IGBT-switch, a constant-current DC power-supply and a large 700 kg inductor for an H ion source, a significant sag of about 5% of arc-current was produced. The sag was reduced by an innovative CCPAPS using two IGBT-switches, a constant-current DC power-supply, a constant-voltage DC power-supply, a inductor and a capacitor. It succeeded in producing a flat arc-pulse with a peak-power of 60 kW (400A 150V) and a pulse width of more than 600 us. Its architecture and performance are described in this paper.