Simultaneous Measurements of Spatial Profiles of Ion and Electron Temperatures Using a Semiconductor Detector Array

A new method is proposed for obtaining radial profiles of both plasma ion (T_i) and electron temperatures (T_e) simultaneously using one semiconductor detector array alone. Furthermore, availability of the new idea of the simultaneous T_i and T_e diagnostics is experimentally demonstrated by the use of a small-sized semiconductor detector array. This novel method for semiconductor T_i diagnostics is proposed on the basis of an alternative “positive” use of a semiconductor “dead layer” as an energy-analysis filter. Filtering dependence of charge-exchange neutral particles from plasmas on the thickness on the order of nm thick SiO₂ layer is used for analyzing T_i ranging from hundreds to thousands eV. In this report, proof-of-principle plasma experiments for the proposed idea are, at first, demonstrated in the GAMMA 10 tandem mirror to verify the availability of this novel idea of distinguishing and identifying each value of T_i and T_e by the use of various thin filtering materials. Furthermore, novel experimental data on radial profiles of T_i and T_e are simultaneously observed and analyzed using a semiconductor detector array along with the development of a Monte-Carlo computer simulation code for analyzing interactions between semiconductor materials and incident particles. The radial profiles of T_i and T_e obtained from semiconductor detectors by the use of the proposed method are found to be in good agreement with those from a charge-exchange neutral-particle T_i analyzer and a microchannel-plate T_e detector. Detailed data and analysis method are represented in the paper.