Lawrence Berkeley National Laboratory

A vacuum arc ion source was modified allowing us to collect ions from arc plasma streaming through an anode mesh. The mesh had a geometric transmittance of 60 percent, which was taken into account as a correction factor. The ion current from twenty-two cathode materials was measured at an arc current of 100 A. The ion current normalized by the arc current was found to depend on the cathode material, with valuesin the range from 5 percent to 11 percent. The normalized ion current is generally greater for light elements than for heavy elements. The ion erosion rates were determined from values of ion currentand ion charge states, which were previously measured in the same experimental system. The ion erosion rates range from 12-94 mu g/C.