Microwave plasma source for remote low energy ion stream

A plasma source capable of delivering a narrow (2 to 3‐in. diameter), low ion energy (10–30 eV), plasma stream has been designed and tested. Microwave plasmas were excited in a 3‐in.‐diam chamber by cw electromagnetic waves (2.45 GHz, 200–1000 W) in the presence of static axial magnetic fields of 875–930 G. Plasma was delivered to the sample via a 12‐in.‐long, 2‐in.‐diam‐metal tube. Ion current densities of several hundred μA/cm2 at gas pressures 1–3×10− 4 Torr (N2, Xe) were achieved at distances of 15–16 in. from the source output.