CHARACTERISTICS OF A FREELY PROGRAMMABLE ICCD DETECTOR FOR MULTICHORD PARTICLE INFLUX MEASUREMENTS ON THE ASDEX-UPGRADE TOKAMAK

The characteristics of a compact space and wavelength-resolving spectrometer-detector arrangement are described which is used to measure spectral line shapes simultaneously along several viewing chords. The system is based upon a freely programmable slow-scan charge-coupled device (CCD) camera gated by an image intensifier tube. Visible and near-UV light emitted near the plasma boundary is collected from up to 12 viewing chords and transmitted to the spectrograph by quartz fibers. Spectra can be recorded with a temporal resolution of 20 ms by means of multiple pixel binning during CCD readout. Integration of the spectral line profiles yield particle fluxes of various low-Z species for ohmically heated helium discharges. The calibration, sensitivity, and signal-to-noise ratio of the system are reconstructed considering each individual element, allowing an easy prediction of the performance of similar applications.