X-ray diagnostic systems for the TJ-II flexible heliac

The set of diagnostics that are being installed in TJ-II are meant to cover the full photon energy range expected in TJ-II during the electron cyclotr on resonance heating phase. The obtained information will be used to evalua te the energy contained in the superthermal electron populations and its po ssible relevance in the global power balance as well as for standard electr on temperature estimations. Two NaI(Tl) detectors located at the equatorial plane of the machine will be used to analyze the highest energy photons (o ver 50 keV). One Si(Li) and a planar Ge detector will be used to obtain the emission spectra between 1 and 100 keV. Tomographic reconstruction of plas ma emissivity (up to 10 keV) will be carried out using four p-n silicon pho todiodes arrays of 16 detectors, located at the same poloidal section. An a dditional camera will be used to detect toroidal asymmetries. (C) 1999 Amer ican Institute of Physics. [S0034-6748(99)70501-0].