Phase I (Final Report)

Abstract

The focus of this proposal was the development of a new instrument capable of in-situ, spatially resolved, measurement of the energy spectra of ions in the edge of a tokamak plasma. The energy spectra of the ions determines the rates of sputtering and erosion of the plasma facing surfaces. The ion spectra in the edge is not easily determined spectroscopically and must be measured in situ since the ions are confined by the strong magnetic fields of the tokamak. Conventional energy analyzers are too large and expensive to install in multiple locations around the tokamak torus. The probes to be developed in this project are compact, low cost, and small enough to be placed inside of specially prepared wall tiles – essentially creating a “smart” plasma facing surface in a tokamak. Phase 1 of this project successfully demonstrated that two key elements of the instrument, the collimator and the energy analyzer, could be fabricated on a single silicon wafer and the combination functioned as designed when tested with an electron beam.