Soft x-ray PHA diagnostic for the electron temperature measurement on EAST

Two soft x-ray Pulse Height Analysis(PHA) systems, based on silicon drift detector(SDD), has been established on the EAST tokamak to measure spectrum of soft x-ray emission, one system consisting of 5 single SDDs is installed on EAST horizontal port A, the other system including one 10-channel SDD linear array on the horizontal port C. At photon energy of 5.9 keV, the energy resolution of 150-180 eV is achieved for the SDD with Peltier cooling, the SDD can maintain a good energy resolution even if the count rates up to 100 kHz. The MCA(Multi-Channel Analyzer) system which is the electronic part of PHA system has been modularized and linked to PC through LAN, the time-resolution and the whole collecting time can be conveniently adjusted by certain detecting software, therefore these PHA systems can be applied in the steady-state long pulse discharges of several minutes. By analyzing the soft x-ray spectra obtained from these PHA systems, the profiles of electron temperature can be readily derived with spatial resolution 7 cm. In this paper, soft x-ray PHA systems on EAST are introduced, some experimental results of electron temperature of EAST typical discharge obtained from the soft x-ray PHA diagnostic is presented. (author)