Superelastic Electron Scattering from Caesium

Author: Daniel Stephen Slaughter

Slaughter, Daniel Stephen, 2007 Superelastic Electron Scattering from Caesium, Flinders University, School of Chemistry, Physics & Earth Sciences

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Abstract

This thesis describes an experimental study of superelastic electron scattering from the 6^2P_3/2 state of caesium. The present status of electron-atom collision studies is initially reviewed and the motivation behind the current work is then presented. A description of the theoretical framework is subsequently provided in the context of the present experimental study, followed by an overview of the several theoretical approaches for describing electron-atom interactions which are currently available. The apparatus and experimental setup used throughout the project are also described in detail. Technical specifications and data are provided, including diagrams (where appropriate) for a laser frequency locking system, electron gun and spectrometer, atomic beam source and data acquisition system. The experimental procedures are explained and discussed, including a detailed analysis of the optical pumping process required to excite the atomic target. A substantial component of this project was to address several potential sources of systematic error and to reduce these wherever possible. All of the errors and uncertainties relevant to the experiment are discussed in chapter 5. In chapter 6 the results of the present superelastic electron scattering experiments are reported for incident electron energies of 5.5eV, 8.5eV and 13.5eV, corresponding to superelastic electron energies of 7eV, 10eV and 15eV. These results are presented as three reduced Stokes parameters, P1, P2, P3 and a coherence parameter, P+ . For comparison, predictions from a number of currently available theories are presented alongside the experimental results. Finally, conclusions are drawn on this work in the context of the current status of electron-atom scattering from alkali-metals.

Keywords: electron scattering,superelastic electron scattering,inelastic electron scattering,caesium,superelastic,electron,atom,collisions,atomic physics,optical pumping,laser excitation
Subject: Physics thesis

Thesis type: Doctor of Philosophy
Completed: 2007
School: School of Chemical and Physical Sciences
Supervisor: Associate Professor Michael J. Brunger