Microradiographs of laser fusion targets: 2-D modeling and analysis

Abstract

A new contact microradiographic system for analyzing laser fusion targets with 2-D modeling and image analysis techniques is described. This system, which uses a monochromatic x-ray source and Kodak highresolution plate emulsion, is sensitive to spherical wall thickness variations (eccentricities) as small as +/-200 A in hollow shells with a mean wall thickness of 1 microm. Measurements of wall thickness and of local and spherical wall thickness variations by radiographic techniques, using 2-D video, digital image analysis, and optical interferometry, are compared.

Fabrication of polystyrene hollow microspheres as laser fusion targets by optimized density-matched emulsion technique and characterization

“…It is estimated that Type I or Type II smaller than 1% in t dt will not degrade target performance, where t is the average wall thickness and dt is the variation about the average. Defects of Type III must be smaller than 0.1% in t dt if they cover an area of t 2 [13].…”

“…Wall-thickness uniformity of the hollow microsphere is simply defined by 1 t max t av t av ¢100 (13) where t max is the maximum wall thickness and t av is the average wall thickness of the microsphere. Wall thickness and non-concentricity of these microshells were also measured by optical interferometry.…”