We used recent phenomenological form factors to calculate the effect of on-shell
two-pion exchange in nucleon-nucleon scattering below the two-pion production
threshold. As expected, the contributions of partial wave amplitudes are all negligible.
We also noticed that the relativistic spin-operator decomposition of the
scattering amplitude is not unique at certain...
The electron, gamma and neutron radiation degradation of III-V semiconductors
and heterojunction bipolar transistors (HBTs) is investigated in this thesis.
Particular attention is paid to InP and InGaAs materials and InP/InGaAs
abrupt single HBTs (SHBTs). Complete process sequences for fabrication of
InP/InGaAs HBTs are developed and subsequently employed to produce...
Herein, a program of research is detailed related to transport through the Si metal oxide semiconductor (MOS) quantum dots fabricated in a process flow compatible with modern ULSI (ultra large scale integrated circuit). Silicon quantum dots were fabricated by placing split gates within a MOSFET structure. Quantum dots of several...
¹¹¹In/Cd perturbed angular correlation (PAC) gamma spectroscopy was used to
study the point defect thermodynamics of tetragonal zirconia (t-zirconia).
PAC can be used to measure, among other things, oxygen vacancy defect
concentrations in t-zirconia. Higher than expected concentrations of oxygen vacancies in
undoped samples were found using PAC. It was...
Liquid surfaces are very abundant in nature. Despite the importance of the liquid
interface in general, experimental molecular-level data was almost completely lacking
prior to the last decade and a half. The intent of this work is to provide a means by
which experimental data on the composition of liquid...
Conventional pictures of nuclear interactions, in which the pion mediates the long/medium range part of the nuclear force, predict an enhancement of the virtual pion cloud in nuclei relative to that in the free nucleon. Jefferson Lab Experiment E91003 measured charged pion electroproduction from Hydrogen, Deuterium, and Helium-3. The longitudinal...
Semi-insulating, powder samples of Cadmium Telluride (CdTe) have been studied using ¹¹¹In Time Differential Perturbed Angular Correlation (PAC) Spectroscopy. The samples have been lightly doped (~10¹² cm⁻³) with ¹¹¹In atoms, which occupy well-defined metal (Cd) lattice sites and act as probes of the local environment. These substitutional donors form a...
We study the four-quark interaction as a first step in understanding the
QCD origin of the nuclear force in nature. We simulate QCD on a 20 x 20 x 20 x 32
space-time lattice with the simplifying quenched and static approximations, and
with the SU(2) gauge group. Recent four-quark simulations...
The N=88 isotones lie on the onset of nuclear deformation and have a complicated nuclear structure. To better understand this region, the nuclear levels of ¹⁵⁰Sm were studied in three different β decay experiments. De-populating γ-rays were measured using the 8π spectrometer, an array of 20 Compton suppressed Ge detectors....
The code is developed for the calculation of the magneto-crystalline anisotropy (MAE) in thin films using a classical Heisenberg hamiltonian with a correction developed by Van Vleck. A Metropolis style Monte Carlo algorithm was used with adequate corrections to accelerate the calculation. The MAE was calculated for the case of...
Nuclear techniques such as perturbed angular correlation (PAC) sample the hyperfine interactions of a large number of probe atoms in specific crystallographic sites. Real crystals contain static defects producing a distribution of electric field gradients (EFGs) that add to the ideal EFG of the crystal at any given probe site....
The Seebeck coefficient is examined in the high temperature limit, using an approach based on a grand partition function containing Hubbard Hamiltonian interaction terms. Although the carriers of interest occupy localized Wannier states, this work is prefaced by the case of delocalized Bloch states, which is examined using Boltzmann transport,...
Aquifer recharge is generally driven by fluids that move from the Earth’s surface to groundwater through the unsaturated zone, also known as the vadose zone. When the vadose zone is fractured, fluids, which may include contaminants, can move through the fracture network as well as the porous matrix. Such a...
The main result of this written dissertation is a mathematical solution to the problem of multiplex recording for high performance tandem time-of-flight mass spectrometry. The prescription is to use a time-lag accelerator in the second stage to match the ion optical properties of the decay fragments to the requirements of...