High speed tangential soft x-ray camera for the study of magnetohydrodynamics instabilities

A fast camera system is being prepared for the TEXTOR tokamak for the investigation of magnetohydrodynamics (MHD) instabilities. The camera will consist of a scintillator screen for conversion of x rays into visible light, a fiberoptic cable for transport of the visible images out of the Textor magnetic field, an electrostatic image converter for amplification and demagnification of the images, and a fast charge-coupled device (CCD) camera for capturing and storing the image data. The purpose of our camera is two-dimensional imaging of magnetic islands and the structure of MHD instabilities. In order to increase the signal intensity and simultaneously reduce statistical noise, we maximize the diameter of the scintillator screen to 100 mm. For good time response, we use fast scintillators and phosphors, and plan to employ a 1 MHz framing CCD camera. MHD events having an amplitude larger than 1% can be observed with a time resolution of 100 kHz and a spatial resolution of 3 cm. In the future, the camera will be used on the Large Helical Device in Japan.