Polycapillary x-ray optics for thin film strain and texture analysis
- Univ. of Albany, NY (United States). Center for X-Ray Optics
- X-ray Optical Systems Inc., Albany, NY (United States)
Polycapillary optics, shaped arrays consisting of hundreds of thousands of hollow glass capillary tubes, can be used to redirect, collimate, or focus x-ray beams from conventional, laboratory-based sources. Multifiber polycapillary collimating optics were placed without system optimization into a number of diffractometer systems. Strain and texture measurements were performed. Measurements on thin films with and without the lens yielded gains of 8--100. Gains are higher in comparison with systems employing pinhole rather than one-dimensional slit collimation. The collimation also resulted in peak symmetrization, which simplified peak shape analysis. Focused beam optics provide even larger gains. Gains of 100 have been demonstrated using polycapillary optics with spot sizes as small as 20 {micro}m. This is of particular significance for providing spatial resolution for low signal applications such as thin films. The inverse dependence of the critical angle for total external reflection on photon energy also results in suppression of high energy photons. This suppression of Bremsstrahlung can allow use of higher tube potentials to increase characteristic line emission. Background suppression from a polycapillary optic soller slit is also enhanced due to the two dimensional collimation and much smaller acceptance angle of the polycapillary optics. Polycapillary optic alignment is also faster and more convenient than the usual parafocusing geometry. The combination of background suppression, intensity gain and increased tube emission by employing polycapillary optics greatly increases the signal to noise ratio for thin film stress analysis.
- OSTI ID:
- 305498
- Report Number(s):
- CONF-971201--
- Country of Publication:
- United States
- Language:
- English
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