Measurements of density, surface recombination coefficient, and diffusion coefficient of hydrogen atoms by L[sub alpha ] laser fluorescence spectroscopy

The technique of laser fluorescence spectroscopy at the Lyman‐alpha (Lα) wavelength in hydrogen was used to measure the temporally and spatially resolved atomic density, the surface recombination coefficient γ, and the diffusion coefficient DH,H2 of the atomic hydrogen in molecular hydrogen. At the same time, it revealed a temporal change of γ, probably due to the change of surface number density of trapped hydrogen atoms. The present technique provides a new and powerful means for determinations of values associated with hydrogen atoms by absolute and local measurements of the atoms at the detection limit of extremely low concentrations.