ABSTRACT
The most important properties of an X-ray laser medium are the peak electron temperature (which controls the ionisation balance and gain) and the density gradients (which control the propagation of the X-ray laser beam along the gain medium). Measurements of these made in X-ray lasing studies using the Asterix laser at the Max Planck Institut fiir Quantenoptik and the Vulcan laser at the Rutherford Appleton Laboratory are described. In particular, the electron temperature diagnostic potential of He-like resonance and satellite lines in Li-like recombination lasers is discussed. The reasons for the increase in output of Ne-like collisional lasers with multi-pulsing of the drive laser are examined. Density gradients have been diagnosed by injecting an X-ray laser beam into another X-ray laser amplifier medium. Measuring and comparing to a simple model the resulting X-ray beam divergences and deflections gives an estimate of the density gradients in the lasing regions.
