A multi-channel spectroscopic system for measuring impurity ion temperatures and poloidal rotation velocities in TJ-II

In this article, we report on the hardware and software of an eight-channel, high-resolution, spectroscopic diagnostic system that has been built for the TJ-II flexible heliac. This system is currently being used on TJ-II to measure impurity ion temperature and poloidal rotation using passive emission spectroscopy. The principal features of the diagnostic include independent focusing of its channels, high sensitivity for performing Doppler measurements in low-density ECR-heated plasmas, as well as a flexible and fast in-house-developed software program for performing integrated data reduction and analysis.