Be Foil "Filter Knee Imaging" NSTX Plasma with Fast Soft X-ray Camera
Authors: B.C. Stratton, S. von Goeler, D. Stutman, K. Tritz, and L.E. Zakharov
Date of PPPL Report: August 2005
Presented at: the Thirty-Second EPS Conference on Plasma Physics (EPS 2005), 27 June – 1 July 2005, Tarragona, Spain.
A fast soft x-ray (SXR) pinhole camera has been implemented on the National Spherical Torus Experiment (NSTX). This paper presents observations and describes the Be foil Filter Knee Imaging (FKI) technique for reconstructions of a m/n=1/1 mode on NSTX. The SXR camera has a wide-angle (28º) field of view of the plasma. The camera images nearly the entire diameter of the plasma and a comparable region in the vertical direction. SXR photons pass through a beryllium foil and are imaged by a pinhole onto a P47 scintillator deposited on a fiber optic faceplate. An electrostatic image intensifier demagnifies the visible image by 6:1 to match it to the size of the charge-coupled device (CCD) chip. A pair of lenses couples the image to the CCD chip.