Beam-Foil Spectroscopy of Sodium between 0.5 and 2 MeV

The optical excitation of a beam of ${\mathrm{Na}}^{+}$ ions by a thin carbon foil has been observed in the spectral range 1100-6000 Å. Ions with a charge state as high as $5^{+}$ were present in the beam after the foil. A large number of untabulated lines has been detected and several identifications are proposed mainly in the Na IV and Na V spectra. The decay along the beam of numerous transitions in Na II and Na III has also been recorded. In a few favorable cases, the resolution of the decay curve gives a useful estimate of the mean life of the corresponding excited state.