Radiographic Detection of 100 Å Thickness Variations in 1-μm-Thick Coatings on Submillimeter-Diameter Laser Fusion Targets

  • David M. Stupin
Conference paper
Part of the Review of Progress in Quantitative Nondestructive Evaluation book series (RPQN, volume 6 A)


We have developed x-ray radiography to measure thickness variations of coatings on laser fusion targets. Our technique is based on measuring the variation in x-ray transmission through the targets. The simplest targets are hollow glass microshells* or microballoons** 100 to 500 μm in diameter (Fig. 1), that have several layers of metals or plastics, 1 to 100 ym thick (Fig. 2). Our goal is to examine these opaque coatings for thickness variations as small as 1% or 0.1%, depending on the type of defect. Using contact radiography we have obtained the desired sensitivity for concentric and elliptical defects of 1%. This percentage corresponds to thickness variations as small as 100 A in a 1-μm-thick coating. For warts and dimples, the desired sensitivity is a function of the area of the defect, and we are developing a system to detect 0.1% thickness variations that cover an area 10 μm by 10 μm.


Thickness Variation Target Designer Uniform Coating Elliptical Defect Glass Microballoons 
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  1. 1.
    D. M. Stupin, K. R. Moore, G. D. Thomas, and R. L. Whitman, J. Vac. Sci. Technol. 20, 1071–1074 (1982).CrossRefGoogle Scholar
  2. 2.
    T. M. Henderson, D. E. Cielaszyk, and R. J. Simms, Rev. Sci. Instrum. 48, 835–840 (1977).CrossRefGoogle Scholar
  3. 3.
    R. L. Whitman and R. H. Day, Appl. Opt. 19, 1718–1722 (1980).CrossRefGoogle Scholar
  4. 4.
    R. L. Whitman, R. H. Day, R. P. Kruger, and D. M. Stupin, Appl. Opt. 18, 1266–1274.Google Scholar
  5. 5.
    R. H. Day, T. L. Elsberry, R. P. Kruger, D. M. Stupin, R. L. Whitman, “X-Ray Microradiography of Laser Fusion Targets,” in: “Eighth International Conference on X-Ray Optics and Microanalysis,” Science Press, Princeton, NJ (1979), pp. 275–282.Google Scholar
  6. 6.
    R. L. Whitman, J. Vac. Sci. Technol. 20, 1359–1361 (1982).Google Scholar
  7. 7.
    B. W. Weinstein, J. Vac. Sci. Technol. 20, 1349–1354 (1982).Google Scholar
  8. 8.
    G. H. Stokes, D. M. Stupin, N. E. Elliott, and M. Graser, Jr., Rev. Sci. Instrum. 56, 2173–2175 (1985).CrossRefGoogle Scholar
  9. 9.
    G. J. Berzins and M. Graser, Jr., App. Phys. Lett. 34, 500–503, (1979).CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1987

Authors and Affiliations

  • David M. Stupin
    • 1
  1. 1.Materials Science and Technology DivisionLos Alamos National LaboratoryLos AlamosUSA

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