Characterization of a Small-Scale Helicon Based Plasma Ion Source

Ion beams are widely used in semiconducting industries, in applications based on accelerators as well as in space propulsion. At UW-Madison, we are developing a small-scale high-density helicon plasma source as an ion source. Helicon sources are known for their high degree of ionization and a small-scale source can provide a high current ion beam in the range of 0.1-10 mA [1]. The source (R = 17 mm, L = 178 mm) is equipped with a helicon antenna that delivers power at 16.2 MHz with RF power up to 850 W. The source is surrounded by two magnetic coils and can provide up to 700 G of axial magnetic field at 5.5 A. With this setup, a stable helicon plasma, as detected by the typical blue Ar-II core was produced. To verify the helicon dispersion behavior, a neural network based on line-ratio spectroscopy is being developed to measure the plasma parameters (n_e ,T_e). The results from the neural network will be validated with the measurement from the laser-induced fluorescence (LIF) diagnostic. The ion beam current will be measured with a Faraday cup. Here, measured plasma parameters and ion beam current will be presented at different operating parameters.