Characteristics of a freely programmable ICCD detector for multichord particle influx measurements on the ASDEX-Upgrade tokamak

Abstract

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.