Efficient method that precisely characterizes laser-target defects more complex than nonconcentricity
An expansion of an efficient, fast Fourier technique for precisely characterizing complex laser target defects is described. The defects characterized are the traditional nonconcentricities and the more complex ellipticites and higher-order wall nonuniformities in single-layered targets. This characterization method uses experimentally derived molybdenum step-wedge data. The molybdenum steps (12.5 micrometer) were exposed to a 45-kV tungsten-bremsstrahlung source and were recorded on holographic plate emulsion. Using the step-wedge data, targets with 6.25 micrometers-wall thickness and diameters of 150 micrometer and 300 micrometer were modeled with nonconcentricities and ellipticities. Sensitivities of +- 1/2 to 1% for nonconcentric defects and +-1.4 to 2.8% for elliptic defects were calculated for target diameters between 300 micrometer and 150 micrometer, respectively. In addition, modeled targets with a combination of nonconcentric and elliptic defects were easily characterized in the presence of film noise.
Presented at the Am. Vacuum Soc. 28th Natl. Symp
- Pub Date:
- October 1981
- Fast Fourier Transformations;
- Laser Targets;
- Lasers and Masers