Time resolved measurements by the pulse height analysis soft x-ray diagnostic on TCV

A single chord, single processing chain, hybrid (analog/digital) pulse height analysis diagnostic has been developed for the TCV tokamak, aiming to provide the evolution of the plasma electron temperature with a software selectable minimum temporal resolution of 100 ms. The high count rate (approximately 65 kHz) together with an energy resolution of 190 eV (at 5.9 keV) were achieved by encoding the data stream with an on-site developed interface amplifier and time generator. The diagnostic was also used to investigate the non-Maxwellian behavior of the electron energy distribution function with strong electron cyclotron resonance heating and to monitor the presence of intrinsic and injected impurities in the 700 eV-20 keV energy range. The conversion of this diagnostic into a real-time control tool is under development.