Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Physics
Methods For Preparing And Characterizing Granular Materials For Electron Yield Measurements, Tom Keaton
Methods For Preparing And Characterizing Granular Materials For Electron Yield Measurements, Tom Keaton
All Graduate Plan B and other Reports, Spring 1920 to Spring 2023
This work presents a systematic study on sample preparation methods and accuracy of electron yield (EY) measurements of highly insulating, granular materials. EY measurements of highly insulating materials, especially those with high EY, are challenging due to the effects of sample charging even for very low fluence electron probe beams. EY measurements of particulates are complicated by: (i) roughness effects from particulate size, shape, coverage, and compactness; (ii) particle adhesion; (iii) substrate contributions; and (iv) electrostatic repulsion and potential barriers from charged particles and substrates. Numerous methods were explored to rigidly affix particles on conducting substrates at varying coverages for …
Electron-Induced Electron Yields Of Uncharged Insulating Materials, Ryan Carl Hoffmann
Electron-Induced Electron Yields Of Uncharged Insulating Materials, Ryan Carl Hoffmann
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Presented here are electron-induced electron yield measurements from high-resistivity, high-yield materials to support a model for the yield of uncharged insulators. These measurements are made using a low-fluence, pulsed electron beam and charge neutralization to minimize charge accumulation. They show charging induced changes in the total yield, as much as 75%, even for incident electron fluences of <3 fC/mm2, when compared to an uncharged yield. The evolution of the yield as charge accumulates in the material is described in terms of electron recapture, based on the extended Chung and Everhart model of the electron emission spectrum and the dual dynamic …