NE-LIKE GE SLAB TARGET STUDIES CARRIED OUT AT RAL

The effect of non-uniform target illumination on the soft X-ray lasing output intensity of the J=2-1 Ne-like Ge transitions as a function of length was investigated. As the degree of nonunifonnity increased with length the Ne-like Ge 23.2 and 23.6 nm J=2-1 transitions did not show exponentiation of output intensity. Using an experimentally measured gain-intensity scaling relationship these results were modelled and good qualitative agreement obtained. The model indicates that for Ge targets which are non-uniformly illuminated, even with peak to valley ratios of up to 3 efficient operation can be achieved at between 2-3x threshold intensity. Further studies of the effect of increasing the separation between the two targets of a double target geometry are also presented.