A.L. Greenwood, A. Nikroo, C.H. Shearer Jr., and J.L. Kaae
General Atomics, P.O. Box 85608, San Diego, California 92186-5608
Thin metallic films deposited by physical vapor deposition are often used in fabrication of inertial confinement fusion targets. Accurate measurement of thicknesses of such films is particularly challenging when the substrate is spherical. We have used several different techniques for measurement of the thickness and uniformity of thin gold films deposited on polymer shells. These techniques include atomic force microscopy, optical transparency, and
x-ray fluorescence spectroscopy. X-ray fluorescence spectroscopy, in particular, offers a non-destructive way of measuring thin films on spherical targets. The accuracy and precision of the measurements will be discussed along with recent work on cylindrical samples. Details of the coating shells will also be presented.
