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Full-Text Articles in Physics
Positron Lifetime Modulation By Electric Field Induced Positronium Formation On A Gold Surface, Daniel J. Higgins
Positron Lifetime Modulation By Electric Field Induced Positronium Formation On A Gold Surface, Daniel J. Higgins
Theses and Dissertations
The purpose of this project is to study the lifetime and annihilation mode of positrons, the antimatter counterpart to electrons, and the formation rate of positronium on a gold surface modified by gold nanoparticles under the influence of radial electric fields measured using two independent systems. The positron annihilation photon pair/triplet spectroscopy system uses a sodium iodide ring detector segmented into six detection regions providing rough position sensitivity to measure the ratio of two to three photon positron annihilation events. An increased rate of three photon annihilation events and a decreased rate of two photon annihilation events are observed when …
Design And Characterization Of A Three-Dimensional Positron Annihilation Spectroscopy System Using A Low-Energy Positron Beam, Stephen M. Jimenez
Design And Characterization Of A Three-Dimensional Positron Annihilation Spectroscopy System Using A Low-Energy Positron Beam, Stephen M. Jimenez
Theses and Dissertations
Previous forays by AFIT into positron research have resulted in the development of a new positron annihilation spectroscopy (PAS) technique and the procurement of a low-energy positron beam system. The primary purpose of this research was to design and build a state-of-the-art PAS laboratory at AFIT capable to address a myriad of DoD solid-state and surface physics questions. The main objectives were to acquire and assemble utilities to operate a positron beam, assemble and configure an ultra-high vacuum (UHV) system for samples, design and build an interface with a magnetic field to propagate positrons onto samples, and create a new …