Broadband extreme-ultraviolet survey spectrometer for short-time-scale experiments.

A fast and inexpensive spectrometer system has been developed to record extreme-UV impurity spectra in a magnetic-fusion-research device. To simplify the vacuum system, light is passed out of the spectrometer's vacuum to the detector with a sodium-salicylate-coated, fiber-optic coupler. This coupler is positioned so that the focal field is nearly flat over its aperture. The system's detector is a microchannelplate- intensified, linear, self-scanning photodiode array. The 1024-pixel array covers a bandwidth greater than 80 nm and is read out once every millisecond. The readout, which is four times faster than the manufacturer's maximum rating, is fully synchronized to the experiment by a locally designed control circuit.