Absorption Spectroscopy in the Extreme Ultraviolet of Light Ions

Absorption spectra and photoionization cross-section measurements of multiply charged ions have been performed by using two laser-produced plasmas, one acting as background continuum radiation source the other as absorbing medium. The basic principles of the experiment are discussed and results for Bell, III, IV ions, in the grazing incidence spectral region, are reported. Measurements of photoionization cross-section are derived by extrapolating to the continuum the known oscillator strength of suitably chosen optically thin lines