[en] Spectroscopic measurements in the range 5 to 2000 A on T.F.R. are presented. This machine is a source of large volume, high temperature (kTsub(e) approximately 2keV) and relatively low density (nsub(e) approximately 8.10¹³cm^-3). The working gas (H₂ or D₂) is contaminated by light (O, C, N) or heavy (Mo, Fe) impurities, the former being fully ionized in the central region of the plasma, the latter existing as highly charged ions with some remaining bound electrons (Mo³⁰⁺). Unknown spectra of molybdenum ions are studied in details in the range 5 - 100 A; spatio-temporal behavior of the various impurity ions are studied between 100 and 2000 A. Radiances (Watts cm^-2sr^-1) are interpreted in terms of ion densities through models which are all based on the coronal approximation either at equilibrium (central part of the plasma during current plateau) or in the transient regime (beginning of the discharge and peripheral zone of the plasma). Total radiation losses are deduced. In the range 1200-2000 A, ion temperature is deduced from Doppler measurements of some light impurity lines