A foil mask spectrometer is described which allows for the simultaneous determination of position, energy, and intensity of monochromatic spots in a Laue diffraction pattern. The instrument may also be used for the quantitative determination of the intensity components corresponding to each energy contained in a spot with harmonic overlap. The spectrometer is uniquely suited to Laue diffraction applications and is demonstrated to be useful for determining unit cell dimensions and systematic absences. This dissertation discusses the characterization of a charge injection device camera system and provides a theoretical basis for selecting a charge transfer device detector. The principles, construction, design, and limiting equations for the foil mask spectrometer are described. Equations for limiting resolution are verified and the correspondence between predicted and observed energy is shown for a variety of crystal systems. The foil mask spectrometer is then used to verify the unit cell dimensions of six compounds and to observe systematic absences due to 2₁ screw axes and unit cell centering conditions. These crystals belonged to four different crystal systems including: cubic, orthorhombic, tetragonal, and monoclinic cells. The crystals had cell volumes from 179.4 ų to 4588.3 ų. Comparison of known and re-determined cells showed good agreement (ratio of known to measured cells = 0.987 ± 0.020). A single procedure was suitable for all unit cell determinations. Some of the crystals represent space groups containing systematic absences normally obscured by harmonic overlap when using the Laue method. These include absences due to 2₁ screw axes (h, k, or 1 = 2n + 1) and cell centering (h + k = 2n + 1). All systematic absences were identified using a combination of multiple linear regression with either stepwise elimination or stepwise inclusion and an F-test for assignment of systematic absence. The methods are discussed in detail and simulations are used to evaluate critical tolerances for future systems.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/288911 |
| Date | January 1997 |
| Creators | Hanley, Quentin Sean, 1963- |
| Contributors | Denton, M. Bonner |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Dissertation-Reproduction (electronic) |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
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