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Full-Text Articles in Physics

Secondary Electron Yield Measurements Of Carbon Nanotube Forests: Dependence On Morphology And Substrate, Brian Wood, Jordan Lee, Gregory Wilson, T. -C. Shen, Jr Dennison Aug 2019

Secondary Electron Yield Measurements Of Carbon Nanotube Forests: Dependence On Morphology And Substrate, Brian Wood, Jordan Lee, Gregory Wilson, T. -C. Shen, Jr Dennison

Journal Articles

Total, secondary, and backscatter electron yield data were taken with beam energies between 15 eV and 30 keV, in conjunction with energy emission data, to determine the extent of suppression of yield caused by carbon nanotube (CNT) forest coatings on substrates. CNT forests can potentially lower substrate yield due to both its inherently low-yield, low-atomic number (Z) carbon composition, and its bundled, high-aspect ratio structure. Rough surfaces, and in particular, surfaces with deep high-aspect-ratio voids, can suppress yields, as the electrons emitted from lower lying surfaces are recaptured by surface protrusions rather than escaping the near-surface region. Yields of multilayered …


Few-Body Dynamics Underlying Postcollision Effects In The Ionization Of H₂ By 75-Kev Proton Impact, M. Dhital, S. Bastola, A. Silvus, Don H. Madison, Michael Schulz Jun 2019

Few-Body Dynamics Underlying Postcollision Effects In The Ionization Of H₂ By 75-Kev Proton Impact, M. Dhital, S. Bastola, A. Silvus, Don H. Madison, Michael Schulz

Physics Faculty Research & Creative Works

We have measured fully differential cross sections (FDCS) for ionization in 75-keVp+H2 collisions for ejected electron speeds close to the projectile speed. The data were analyzed in dependence on both the electron emission angle and the projectile scattering angle. Pronounced postcollisional effects between the projectile and the ejected electrons were observed. Significant differences between experiment and theory and between two conceptually very similar theoretical models were found. This shows that in the region of electron-projectile velocity-matching the FDCS is very sensitive to the details of the underlying few-body dynamics.


Suppresion Of Electron Yield With Carbon Nanotube Forests: A Case Study, Brian Wood, Jordan Lee, Gregory Wilson, T.-C. Shen, Jr Dennison May 2019

Suppresion Of Electron Yield With Carbon Nanotube Forests: A Case Study, Brian Wood, Jordan Lee, Gregory Wilson, T.-C. Shen, Jr Dennison

Conference Proceedings

Electron emission of carbon nanotube (CNT) forests grown on silicon substrates was measured to investigate possible electron yield suppression due to the composition and morphology of CNT forests. CNT forests are vertically-oriented tubular formations of graphitic carbon grown on a substrate; these have been widely investigated for their extreme properties in optical, electrical, and mechanical aspects of physics and material sciences. CNT coatings are good candidates for yield reduction, in analogy with the near-ideal blackbody optical properties of CNT forests. Carbon with its low atomic number has an inherent low yield due to its low density of bulk electrons. Furthermore, …