A Small Electron Cyclotron Resonant Plasma-Based Neutral-Flux Ionizer

Rev. Sci. Instrum.,  61, 3473-3478, (1990).

Cain, B. L., Ruzic, D. N.

The design and operation of a neutral-hydrogen flux detection system is described. The central feature of the detector is an inductively driven electron cyclotron resonance heated (ECRH) discharge, which functions as the neutral-flux ionizer. The prominent features of the ionizer are its small (5×3×3 cm³) size and excitation of the ECRH mode using a 200-W, 30-MHz rf driver and static magnetic field level near 30 G. The ability of the system to ionize 910-eV neutral-hydrogen fluxes with subsequent detection in a high resolution energy analyzer is shown. The detection efficiency of the ionizer was found to be 6×10⁻⁴, based on scattering and charge exchange cross sections measured using a methane charge exchange cell. The ionizer has potential applications in angle-resolved reflected neutral-flux measurements and in beam-plasma interaction analysis.