Real-time signal analysis on the TCV PHA diagnostic

A pulse height analysis (PHA) x-ray system has been successfully implemented on the tokamak TCV, aiming at a low cost monitor system of the plasma electron temperature and impurity content. To meet the need for high throughput and fast acquisition, mandatory in tokamaks with relatively short pulse duration and high-energy fluxes, the original germanium detector is being replaced by a Silicon Drifted Detector and the traditional dedicated analog electronics for a Digital X-Ray Signal CAMAC compatible unit. A separate DSP system will provide higher quality spectra with an increased time resolution. An in-site developed DSP-based VME intelligent module, specially designed for real-time plasma control, is being programmed for fast data acquisition and simultaneous real-time data processing. The current goal is to obtain spectra with sufficient statistics every 10 ms, fit the data in real-time, evaluate the quality of the measurement and adjust remotely controllable x-ray PHA filters. and apertures and finally provide the PHA data to the TCV control system. The final goal is,to provide real-time data analysis with a temperature and impurity content monitor that can be used for machine feedback. Trials with the SDD and the DSP unit have shown that this is achievable. (C) 2003 American Institute of Physics.