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Full-Text Articles in Physical Sciences and Mathematics
Relaxation Of Radiation Effects In Polymers, Alexandra Hughlett Nelson
Relaxation Of Radiation Effects In Polymers, Alexandra Hughlett Nelson
Physics Capstone Projects
Radiation can create atomic-scale defect states in polymers, leading to changes in their optical, electrical and mechanical properties. Recent studies of polymers have shown that these defect states are sensitive to oxygen or water exposure. It is believed that oxygen cause the number of defect states to decrease and the polymers to revert to their original states. However, the time scale of this regression is not known. This experiment quantified the time that it takes five polymers to recover and the extent of said recovery; polypropylene (PP), low density polyethylene (LDPE), fluorinated ethylene propylene (FEP), polymide (PI), and poly ether …
Dynamic Secondary Electron Emission In Rough Composite Materials, Leandro Olano, Maria E. Dávila, John R. Dennison, Petronilo Martín-Iglesias, Isabel Montero
Dynamic Secondary Electron Emission In Rough Composite Materials, Leandro Olano, Maria E. Dávila, John R. Dennison, Petronilo Martín-Iglesias, Isabel Montero
All Physics Faculty Publications
The interaction of ionizing radiation with matter is of critical importance in numerous areas of science and technology like space and vacuum technology and even medicine and biotechnology. Secondary electron emission is a consequence of electron irradiation on materials. We achieve extremely low secondary electron emission yield values smaller than 0.2, even up to incident electron energies ~1 keV, due to an undocumented synergy between neighbouring metal and dielectric domains in composite samples. To investigate this experimental discovery, we propose a simple 3D model where the dielectric and metallic domains are arranged in parallel and interleaved. The proposed surface profile …