Ion source metal‐arc fault current protection circuit

Ion sources can be damaged by arcs between metallic components of the source if these arcs are permitted to last. The negative‐biased low‐work‐function converter in a surface conversion negative ion source is especially susceptible to metal‐arc breakdown damage. Here an electronic circuit for minimizing the damage caused by such an arc is described. The circuit uses a transistor switch and an inductor in series with the converter bias power supply to limit the damage during the metal‐arc breakdown.