Mechanisms and kinetics of silicon under dynamic compression
Abstract/Contents
- Abstract
- This thesis analyzes the dynamic material response of crystalline silicon to laser-driven shock loading. As a shockwave passes through the silicon, it generates a high-pressure, high-temperature environment that causes the material lattice to compress, deform, adopt new high-pressure phases, and eventually enter a melt state. Measuring these responses utilizes an ultra-bright, ultrafast x-ray source capable of capturing the lattice and atomic motions in-situ. The first experiment (Chapter 3) characterizes the loading source, a high-power optical laser at the Matter in Extreme Conditions endstation of the Linac Coherent Light Source. Analysis of the drive system optimized the experimental setup to send steady-pressure, spatially-uniform shockwaves through the silicon. The second experiment (Chapter 4) builds on the results of the first experiment, driving high-pressure (> 20 GPa) shocks through pure crystalline silicon samples. Using a setup configuration that places the x-rays transverse to the optical drive laser beam, this experiment takes simultaneous, ultrafast x-ray diffraction and direct x-ray imaging data of the lattice response. A series of focused spatial and temporal scans determines the kinetics of the elastic, inelastic, and melt waves. Additionally, wide field-of-view x-ray imaging spatially resolves these responses and illuminates an intermediate elastic wave. The third experiment (Chapter 5) analyzes additional data to extract the density of the imaged silicon melt in-situ, a long-standing challenge in the dynamic compression community. It establishes a positive trend between drive pressure and melt density while simultaneously quantifying the change in transformed material volume. A final experiment (Appendix B) examines the photon flux on-target in the Matter in Extreme Conditions endstation. It determines the effect of beamline configuration on the delivered number of x-rays - a critical value for expanding the results of this thesis to new low-transparency and/or high-Z materials.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2019; ©2019 |
| Publication date | 2019; 2019 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Brown, Shaughnessy Brennan |
|---|---|
| Degree supervisor | Cappelli, Mark A. (Mark Antony) |
| Degree supervisor | Mao, Wendy (Wendy Li-wen) |
| Thesis advisor | Cappelli, Mark A. (Mark Antony) |
| Thesis advisor | Mao, Wendy (Wendy Li-wen) |
| Thesis advisor | Nagler, Bob |
| Degree committee member | Nagler, Bob |
| Associated with | Stanford University, Department of Mechanical Engineering. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Shaughnessy Brennan Brown. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2019. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2019 by Shaughnessy Brennan Brown
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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