Multichannel light detector system for visible continuum measurements on Alcator C

A spatially resolving visible light detector system has been constructed and used to measure continuum radiation in the wavelength region near 5360 A on the Alcator C tokamak. The instrument measures the line integral brightnesses from 20 chords through the plasma. For high-electron temperature regimes and relatively line-free wavelength regions, Z/sub eff/(r, t) is inferred from Abel inverted brightness profiles. During the steady-state portion of the discharge, Z/sub eff/(r) is usually found to be constant within 10% out to r/a = 0.75