<title>Intensity distribution of the focal lines of the prepulse and mainpulse at the solid target surface</title>

Abstract

At the Prague Asterix Laser System (PALS) of the Academy of Sciences of Czech Republic the former Asterix IV iodine laser of the Max-Planck-Institut fur Quantenoptik is currently re-installed. For the soft 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 important. Applying the prepulse technique there are two possibilities, either the main beam a d the prepulse beam are focused by the same focusing optics or the two different beams are focused by two optical systems separately. It is important to characterize the physical properties of the both line foci, i.e. their intensity distribution in two dimensions, since their energy ratio is giving only a mean value and not the actually existing non-uniformities along or across the focal line. By using two different focusing optics it is possible that the two lien foci do not have exactly the same width at full-width-half-maximum. In order to realize a well defined prepulse line focus it is important to measure the exact intensity distribution in two dimensions. We concept a method to obtain quantified 2D focal images and we present preliminary experimental results using a cylindrical lens array as well as using only a single cylindrical lens in combination with a spherical focusing lens.