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.
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