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Pulse propagation of sound, light, and electrons

Shawn A Hilbert, University of Nebraska - Lincoln


While electrons have been used for spatial studies since the 1930’s, temporal measurements with electrons are a newer innovation. Using ultrafast electron diffraction, Ahmed Zewail won the Nobel Prize in 1999 for his development of molecular movies. This spurred a movement to improve the temporal resolution by producing smaller-width electron pulses. This thesis describes an electron source that is capable of producing femtosecond electron pulses and its use in testing fundamental physics. Theoretical studies are used to guide the progress of this source in probing fundamental physics. As these electron pulses reach closer to the diffraction limit, quantum mechanical descriptions of these pulses could become more sensible than classical descriptions. A firm background in wave propagation can provide the necessary outlook to distinguish these wave-like properties. In this thesis, an acoustic apparatus is developed that can provide such a background. Physical demonstrations of quantum effects, such as level splitting, avoided crossing, and the formation of band gaps, are done with this acoustic system. This system also lends itself to optical analogies which are presented. These analogies could be used to predict the dynamics of the electron pulses from our source. Temporal limits of the electron source are explored at various operating parameters, which provide information on the emission process. These findings show that the source can be coupled with a drift tube to make a time-of-flight energy analyzer that could rival state-of-the-art devices. The possibility of fundamental studies, such as testing the time dependence of the Pauli exclusion principle, is explored with this source. A theoretical model is used to determine the viability of coupling this source with dispersion compensation techniques to produce pulse widths in the attosecond domain. The wide spread of uses shows that the source is not only useful but versatile.

Subject Area

Atoms & subatomic particles|Optics

Recommended Citation

Hilbert, Shawn A, "Pulse propagation of sound, light, and electrons" (2009). ETD collection for University of Nebraska - Lincoln. AAI3350448.