The main objective of this thesis is to perform a study of and optimize the most direct and practical gas mixture composition inside the Radial Time Projection Chamber for the Barely-Offshell Nucleon Structure (BONuS 12) detector for use in the CLAS 12 detector in Experimental Hall B at Thomas Jefferson National Accelerator Facility (JLab). The optimization of these conditions will enhance the performance and resolution of the detector. The original BONuS 6 experiment utilized a gas composition of 80 % He and 20% Dimethyl Ether (DME). With the extensive 12 GeV energy upgrade constructed at JLab and the new BONuS 12 detector established , it is imperative that the gas composition utilized, is best suited to facilitate the experimental needs and demands. BONuS 12 is an experiment designed to measure the momentum of recoiling spectator protons down to 70 MeV/c. This technique will extract the structure function Fn 2 at large x from 0.1 up to 0.8 over a significant range in Q2 and W from the nucleon mass, with a beam energy of 11 GeV, enabling us to essentially select free neutrons.

Generally, the electronic stability of aluminum clusters is associated with either closed electronic shells of delocalized electrons, or aluminum in the +3 state. To explore alternative routes for electronic stability in aluminum oxide clusters, theoretical methods were used to examine the geometric and electronic structure of AlnOm (2≤n≤7; 1≤m≤10) clusters. Two types of electronically stable clusters with large HOMO-LUMO gaps were identified the first being Al2nO3m clusters with a +3 oxidation state on the aluminum, and the second being planar clusters such as Al4O4, Al5O3, Al6O4, and Al6O5. The structures of the planar clusters have external Al atoms bound to a single O atom. Their electronic stability can be explained by the multiple valence Al sites with the internal Al atoms having an oxidation state of +3, while the external Al atoms have an oxidation state of +1. The formation of AlnOm+ clusters with high concentrations of oxygen were found experimentally. To determine the stability of such clusters theoretical methods were used to examine the geometric and electronic structure of these clusters (2≤n≤7; 1≤m≤10). The structures were found to be below average in terms stability, implying formation in a low collision environment.

Non-destructive methods of material interrogation are used to locate hidden explosives and thwart terrorism attempts. In one such method materials are bombarded with neutrons which react with the nuclei of the atoms within causing a de-excitation process emitting a gamma-ray. The spectrum displayed by the collection of these gamma-rays gives valuable information regarding the material’s elemental make-up. It has been hypothesized that gamma-rays from neutron-induced gamma-ray reactions on light elements with atomic numbers less than 20, including most of the gamma-rays of interest in explosives detection, are Doppler-broadened. This thesis focuses on the gamma ray spectra from the 4438 keV gamma ray in the 12C (n, n’γ) reaction wherein Doppler broadening was investigated. A graphite sample was exposed to 14 MeV neutrons and the 12C gamma ray spectra collected using an HPGe detector positioned at four different angles with respect to the neutron beam; near 00, 450, 900 and 1350. No other experimental parameter was changed. The resultant gamma ray spectra indicated Doppler broadening had occurred.

The observation of a permanent electric dipole moment (EDM) in a non-degenerate system would indicate the violation of discrete symmetries of Time reversal (T) or combined application of Charge (C) and Parity (P) symmetry violation through the CPT theorem. The diamagnetic 225Ra atom with nuclear spin I=1/2 is a favorable candidate for an EDM search. Experimental sensitivity to its EDM is enhanced due to its high atomic mass and the increased Schiff moment of its octupole deformed nucleus. An experimental setup is developed where laser cooled neutral radium atoms are collected in a magneto-optical trap (MOT). The collected atoms are transported 1 meter with a far off-resonant optical dipole trap (ODT) and then the atoms are transferred to a second standing-wave ODT in an experimental chamber. The atoms are then optically polarized and allowed to Larmor precess in parallel and antiparallel electric and magnetic fields. The difference between the Larmor precession frequency for parallel and antiparallel fields is experimentally determined to measure the EDM. This thesis is about the first measurement of the EDM of the 225Ra atom where an upper limit of |d(225Ra)|<5.0*10-22 e cm (95\% confidence) is reached.

Inelastic collisions between dipolar molecules, assumed to be trapped in a static electric field at cold (> 10−3K) temperatures, are investigated and compared with elastic collisions. For molecules with a Λ-doublet energy-level structure, a dipole moment arises because of the existence of two nearly degenerate states of opposite parity, and the collision of two such dipoles can be solved entirely analytically in the energy range of interest. Cross sections and rate constants are found to satisfy simple, universal formulas. In contrast, for molecules in a Σ electronic ground state, the static electric field induces a dipole moment in one of three rotational sublevels. Collisions between two rotor dipoles are calculated numerically; the results scale simply with molecule mass, rotational constant, dipole moment, and field strength. It might be expected that any particles interacting only under the influence of the dipole-dipole interaction would show similar behavior; however, the most important and general result of this research is that at cold temperatures inelastic rate constants and cross sections for dipoles depend strongly upon the internal structure of the molecules. The most prominent difference between the Λ-doublet and rotor molecules is variation of the inelastic cross section with applied field strength. For Λ-doublet dipoles, cross sections decrease with increasing field strength. For rotor dipoles, cross sections increase proportionally with the square of field strength. Furthermore, the rate constants of the two types of molecules depend very differently on the angular orientations of the dipoles in the electric field.

The gyromagnetic ratio of bound particles is an active field of experimental and theoretical research. Early measurements of corrections to the bound g-factor came from experiments involving hydrogen-like ions. As the sensitivity of such experiments has increased, it has become possible to instead use them to measure the electron-ion mass ratio -- but only if the theoretical bound g-factor is known with sufficient precision for these systems. By constructing an effective nonrelativistic Lagrangian, we derive leading order binding and recoil corrections for systems comprised of particles with arbitrary spin. Lagrangians for spin one-half and spin one-theories are developed, before moving on to the more general case of arbitrary spin. In each case, an effective nonrelativistic Lagrangian taking into account all relevant terms is constructed. The coefficients of this Lagrangian are then fixed by calculating scattering processes in both the relativistic and nonrelativistic theories. A relativistic framework for dealing with particles of arbitrary spin is considered. In this framework the relevant terms in the scattering process are heavily constrained by the symmetries required of the electromagnetic current. This allows the determination of an effective Lagrangian valid for arbitrary spin. It is found that the only coefficients which depend upon the spin of the particle in question involve derivatives of the magnetic field. This general form is consistent with the previously derived Lagrangians for spin one-half and spin one particles. With this effective nonrelativistic Lagrangian, the leading order binding and recoil corrections to the bound gyromagnetic ratio are calculated. These corrections are found to be universal, independent of the spin of the particles involved. This is understood as a consequence of the Bargmann-Michel-Telegdi equation.

This work is comprised of the study of two magneto-optical phenomena: the Kerr effect and the Faraday effect. Neutron physics experiments often utilize polarized neutrons, and one method to generate or guide polarized neutrons involves the use of a system of magnetic super-mirrors. Experience shows that the magnetization of the super-mirror may decay with time; therefore, we implemented the surface magneto-optical Kerr effect (SMOKE) to study the temporal behavior of the magnetization of a magnetized remnant super-mirror sample, where a sensitivity of 0.1 mrad was obtained. Unique to our set-up was the method in which the various magnetization directions were probed. The sample was magnetized prior to insertion into the set-up, and a high precision rotational stage was used to manually rotate the sample to effectively generate a reversal of the magnetic field. Multiple samples from a larger super-mirror specimen were tested, in which no change in the magnetization was detected for one month after sample magnetization. Further studies could increase the sensitivity of the experiment, potentially rendering the method as an application for real-time magnetization monitoring. Polarized 3He nuclei are often used as an effective polarized neutron target at various laboratories, including Jefferson Lab, through the use of spin-exchange optical pumping in a glass cell constructed of GE-180. Utilizing the nuclear spin optical rotation to measure the Faraday effect of polarized 3He would develop a new procedure for polarization monitoring, establish a powerful tool to diagnose the wall properties and thicknesses of the cells used, and the determination of the frequency independent magnetic component of the polarizability would ultimately lead to the extraction of the spin polarizability of 3He. Furthermore, this study has the future implications of being the pioneer experiment for terrestrial dark matter studies. A new triple modulation technique was devised, where a sensitivity of 60 nrad was obtained, and the first ever extraction of the Verdet constant of GE-180 was recorded, an important factor in wall thicknesses and diagnostic investigations for Jefferson Lab. However, a measurement of the nuclear spin optical rotation of a polarized 3He target was not realized, as the measured polarization suggests a Faraday rotation just below the 60 nrad threshold. Nevertheless, the devised triple modulation method proves to be a very sensitive probe in Faraday effect studies, and additional examination of the polarized target for the production of a larger polarization, should yield a measurement of the nuclear spin optical rotation of polarized 3He.

Beams of light can carry spin and orbital angular momentum. Spin angular momentum describes how the direction of the electric field rotates about the propagation axis, while orbital angular momentum describes the rotation of the field amplitude pattern. These concepts are well understood for monochromatic beams, but previous theoretical studies have constructed polychromatic superpositions where the connection between angular momentum and rotation of the electric field becomes much less clear. These states are superpositions of two states of light carrying opposite signs of angular momentum and slightly detuned frequencies. They rotate at the typically small detuning frequency and thus we call them slowly rotating modes of light. Strangely, some of these modes appear to rotate in the direction opposing the sign of their angular momentum, while others exhibit overall rotation with no angular momentum at all! These findings have been the subject of some controversy, and in 2012, Susanna Todaro (HMC ’12) and I began work on trying to shed light on this “angular momentum paradox." In this thesis, I extend previous work in theory, simulation, and experiment. Via theory and modeling in Mathematica, I present a possible intuitive explanation for the angular momentum paradox. I also present experimental realization of slowly rotating spin superpositions, and outline the steps necessary to generate slowly rotating orbital angular momentum superpositions.

The space simulation chambers at Arnold Engineering Development Complex (AEDC) allow for the testing and calibration of seeker sensors in cryogenic, high vacuum environments. During operation of these chambers, contaminant films can form on the components in the chamber and disrupt operation. Although these contaminant films can be composed of many molecular species, depending on the species outgassed by warm chamber components and any leaks or virtual leaks (pockets of gas trapped within a vacuum chamber) that may be present, water vapor is most common, and it will be the focus of this dissertation. In this dissertation, some properties of the water molecule and low pressure ice are reviewed with a focus on the optical properties. The method of angular coefficients is utilized to calculate flux distributions for general three dimensional situations and the program written is applied to a model of the AEDC 10V space simulation chamber. The optical effects of varying amounts of contamination on a generic germanium window and gold mirror, along with the effects on two components specific to the space chambers, is determined. Also, an experiment to measure the thickness and other properties of contaminant films is discussed, and initial results are given for the first two tests of the experimental setup.

In this thesis, energy levels, lifetimes, oscillator strengths and transition probabilities of Mg VII have been calculated. The Hartree-Fock (HF) and Multiconfiguration Hartree-Fock (MCHF) methods were used in the calculations of these atomic properties. We have included relativistic operators mass correction, spin-orbit interaction, one body Darwin term and spin-other-orbit interaction in the Breit-Pauli Hamiltonian. The configurations, (1s2)2s22p2, 2s2p3,2p4, 2s22p3s, 2s22p3p,2s2p2(4P)3s and 2s22p3d which correspond to 52 fine-structure levels, were included in the atomic model for the Mg VII ions. The present results have been compared with NIST compilation and other theoretical results, and generally a good agreement was found.