A novel electro-optical probe (EOP) has been developed to characterize
the spatial uniformity of various plasma parameters. Spatially resolv
ed electron density and energy distribution function, neutral and char
ged particle densities, as well as ion flow velocity are determined by
the EOP. The design of the EOP combines a Mach probe, back-to-back ch
arge collectors, and a collimated optical fiber. The light collection
angle of the optical fiber is limited by recessing the fiber in a cera
mic tube. The line-of-sight integration length of the plasma emission
is bounded by the charge collector disk. A spatial resolution of 2.4 c
m is obtained by the present design of the EOP. The ion flow velocity
perpendicular to the charge collector surface is determined by the rat
io of the ion saturation currents of the two counter facing charge col
lectors. Localized actinometry, that combines spatially resolved optic
al emission spectra and electron energy distribution functions, is use
d to determine the density of atomic chlorine and fluorine radicals. T
he spatial distribution is obtained by scanning the EOP across the pla
sma volume. (C) 1998 American Institute of Physics. [S0034-6748(98)036
09-0]