 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. |
