Thickness distribution for gold and copper electroformed hohlraums

Some preliminary experiments have been performed to determine the effect of mandrel geometry and plating bath composition on the thickness uniformity of gold and copper electroformed hohlraums. It was observed that for gold p lating, the edge radius has a dramatic influence on uniformity in a directi on opposite that expected (i.e. uniformity worsened with larger radius) and that extension of the front small-diameter cylinder gave a slight improvem ent in hohlraum symmetry. In the case of copper plating it was found that, as expected, reduced metal concentration improved uniformity, however, it w as also found that the selection of additives has an even more pronounced e ffect.