Emittance Measurements of High Charge State Argon Beams from a PIG Source

The emittances of beams of Ar4+ to Ar8+ have been measured in the axial and radial planes. The extraction voltage was 10 kV and the magnetic field was varied from about .5 to .6 Tesla. The anode slit was varied in its distance from the arc which was run both dc and pulsed. The emittance was found to be nearly independent of charge state but to increase with total beam current. A small bowing of the arc column was discovered, which made evaluation of mirror field effects difficult.