At the Rijnhuizen Tokamak Project tokamak spectrometers are used to di
agnose the velocity distribution and abundances of impurity ions. Quan
tities can be measured as a function of time, and the temporal resolut
ion depends on the line emissivity and can be as good as 0.2 ms for th
e strongest lines. Several spectrometers, equipped with a charge-coupl
ed device array, are being used with spectral ranges in the visible, t
he vacuum UV and the extreme UV. (C) 1997 Elsevier Science S.A.