The TEXT upgrade vertical interferometer

A far‐infrared interferometer has been installed on TEXT upgrade to obtain electron density profiles. The primary system views the plasma vertically through a set of large (60‐cm radial×7.62‐cm toroidal) diagnostic ports. A 1‐cm channel spacing (59 channels total) and fast electronic time response is used, to provide high resolution for radial profiles and perturbation experiments. Initial operation of the vertical system was obtained late in 1991, with six operating channels.