Ar. Prag et al., Intensity distribution of the focal lines of the prepulse and mainpulse atthe solid target surface, J PHYS IV, 11(PR2), 2001, pp. 601-604
At the Prague Asterix Laser System (PALS) the former Asterix iodine laser o
f the Max-Planck-Institut fur Quantenoptik is currently re-installed. For t
he x-ray laser experiments that will be performed in the near future a well
defined focal line at the position of the target surface is crucial. Apply
ing the prepulse technique there are two possibilities, either the main bea
m and the prepulse beam are focused by the same focusing optics or the two
different beams are focused by two optical systems separately. It is import
ant to characterise the intensity distribution of the both line foci in two
dimensions (along and across the focal line), since their energy ratio is
giving only a mean value and not the actually existing non-uniformity's alo
ng or across the focal line. By using two different focusing optics it is p
ossible that the two line foci do not have exactly the same width. In order
to realise a well defined prepulse line focus it is necessary to measure t
he intensity distribution in two dimensions. We concept a method to obtain
quantified two-dimensional focal images and we present preliminary experime
ntal results using a cylindrical lens array as well as using only a single
cylindrical lens in combination with a spherical focusing lens.