We are developing an in-situ micro-plasma spectrometer for low energy ions in the plasma edge that requires modest resources and is easily replaced. The entire instrument is fabricated from a wafer of high-conductivity silicon. Ions enter... more
We are developing an in-situ micro-plasma spectrometer for low energy ions in the plasma edge that requires modest resources and is easily replaced. The entire instrument is fabricated from a wafer of high-conductivity silicon. Ions enter microscopic channels and are deflected based on their energy-percharge ratio. Ten channels operate in parallel to increase the signal-to-noise ratio of the instrument. Because the ions of interest are typically low energy, less than 100 eV, conventional solid state detectors have too high an energy threshold and conventional microchannel plate detectors require too large a pre-acceleration potential. The key advance in the instrument described here is an integrated micro-Faraday cup structure designed to capture and record single ions. The Faraday cups are designed to require many bounces before ions escape back into the instrument energy band while allowing for evacuation of the ions to prevent pressure build up in the Faraday cup pocket. We will ...
