Production and analysis of multiply-charged ions in the Cornell electron beam ion source

An Electron Beam Ion Source (EBIS) which produces multiply-charged ions to be used in atomic physics collision and other experiments has been designed and constructed. The source utilizes a conventional solenoid magnet to produce the magnetic field confining the externally launched electron beam. Some of the novel features of the source are: 1) drift tubes made from stainless steel mesh to improve pumping in the interaction region of the source, 2) the ionization region is pumped on by a 140 l/sec distributed sputter-ion pump which encloses this region, and 3) the axial trap supply voltages are controlled by an 8 bit microprocessor. The source has been working reliably for over a year. Low energy 300 - 800 qeV H-like ions (C5+), He-like ions (C4+, N5+, O6+) and multiply-charged ions of noble gases such as Ne6+ have been produced by 1.0 - 2.0 kV, 0.07 - 0.20 A electron beams. The pressure in the electron gun interaction and extraction regions of the source range from 2.0 - 5.0 x 10-9 Torr. The source is relatively simple and operates reliably and reproducibly, an attractive feature in atomic physics experimental arrangements