Electron temperature profile measurements using variable energy x-ray detection

Authors: J. Maddox, L. Delgado-Aparicio, N. Pablant, K.W. Hill, M. Bitter, J.E. Rice, M.L. Reinke, A. Hubbard, P. Efthimion, B. Stratton, S.Wolfe

Abstract: By using a multi-energy soft x-ray (ME-SXR) diagnostic, simultaneous measurements of a variety of plasma parameters is demonstrated for magnetically conned fusion (MCF) plasmas. A prototype installed at C-Mod uses a Pilatus2 2D pixelated x-ray detector in which each individual pixel has a user-controlled minimum-energy threshold, with 13 energy threshold levels between 4 keV and 16 keV, at 1 keV intervals. Characteristic line-emission from medium and high-Z impurities can be isolated using appropriate energy thresholds. Detection of soft x-ray continuum intensities in line-free regions at dierent energy thresholds allows an line-integrated electron temperature to be deduced fromthe dependence of continuum emission with photon energy. The electron temperature is measured in a variety of plasma conditions with temporal resolution of 10 ms and spatial resolution of approximately 3 cm, and is in reasonable agreement with electron cyclotron emission (ECE) electron temperature measurements.
_________________________________________________________________________________________________

Download PPPL-5267 (pdf 2.9 MB 17 pp)
_________________________________________________________________________________________________