Spatial imaging detector system for pulsed plasma extreme ultraviolet diagnostics

Abstract

A spectroscopic instrumentation system is described which forms one-dimensional monochromatic EUV images of pulsed plasma sources. The system uses a small monochromator and a 22 anode microchannel plate detector to simultaneously view 22 chords of the plasma at the wavelength of a given impurity emission with 100 μs resolution. Brightness profiles are measured and stored in a minicomputer at up to 400 time points during a single discharge. If the discharge is cylindrically symmetric, this data can be Abel inverted directly to produce the volume emission rates and impurity density profiles during the discharge. The design, construction, and testing of the system are described, as well as its performance on the Alcator A tokamak.