Initial Operation of the NSTX Fast Tangential Soft X-Ray Camera
Authors: B.C. Stratton, R. Feder, S. von Goeler, G.F. Renda, J.L. Lowrance, and V.J. Mastrocola
Date of PPPL Report: May 2004
Presented at: the 15th Topical Conference on High-Temperature Plasma Diagnostics, 19-22 April, 2004, San Diego, CA; proceedings to be published in the Review of Scientific Instruments.
Fast, two-dimensional, soft x-ray imaging is a powerful technique for the study of MHD instabilities in tokamak plasmas. We have constructed an ultra-fast frame rate soft x-ray camera for the National Spherical Torus Experiment. It is based on a recently developed 64 x 64 pixel CCD camera capable of capturing 300 frames at up to 500,000 frames per second. A pinhole aperture images the plasma soft x-ray emission (0.2-10 keV) onto a P47 scintillator deposited on a fiber-optic faceplate; the scintillator visible light output is detected and amplified by a demagnifying image intensifier and lens-coupled to the CCD chip. A selection of beryllium foils provides discrimination of low-energy emission. The system is installed on NSTX with a wide-angle tangential view of the plasma. Initial plasma data and an assessment of the system performance are presented.