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Abstract: This paper is focused on the soft X-ray tomography system set-up at Tore Supra (DTOMOX) and the recent developments made to get precise information about plasma features from a raw or inverted data. The ultimate aim is not only to use this information in real time for visualisation but also for potential feedback, with a particular emphasis on the optimisation of the reconstruction technique and on simple analysis tools developed for an automatic treatment of these inverted data. Recent progress made on the optimisation of free parameters used for the tomographic inversion will be explained. Finally, future techniques using advanced imaging detector will be presented. In particular, preliminary investigation on the use on Tore Supra of Gas Electron Multiplier (GEM) detector for imaging purposes will be described also including some first observations in situ. [Copyright &y& Elsevier]

A triple gas electron multiplier (GEM) detector has been built and characterized in a collaboration between ENEA, INFN and CEA to develop a soft X-ray imaging diagnostic for magnetic fusion plasmas. It has an active area of 5×5cm2, 128pixels and electronics in counting mode. Since burning plasma experiments will have a very large background of radiation, this prototype has been tested with contemporary X-ray, neutron and gamma irradiation, to study the detection efficiencies, and the discrimination capabilities. The detector has been preliminarily characterized under DD neutron irradiation (2.45MeV) up to 2.2×106 n/s on the detector active area, showing a detection efficiency of about 10−4, while the detection efficiency of X-rays is more than three orders of magnitude higher. The detector has been also tested under DT neutron flux (14MeV) up to 2.8×108 n/s on the whole detector, with a detection efficiency of about 10−5. The calibration of the γ-rays detection has been done by means of a source of 60Co (gamma rays of energy 1.17MeV and 1.33MeV) and the detection efficiency was found of the order of 10−4. Thanks to the adjustable gain of the detector and the discrimination threshold of the electronics, it is possible to minimize the sensitivity to neutrons and gamma, and discriminate the X-ray signals even with very high radiative background. [ABSTRACT FROM AUTHOR]