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This dissertation describes a variety of studies meant to improve the analytical performance of inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation (LA) ICP-MS. The emission behavior of individual droplets and LA generated particles in an ICP is studied using a high-speed, high frame rate digital camera. Phenomena are observed during the ablation of silicate glass that would cause elemental fractionation during analysis by ICP-MS. Preliminary work for ICP torch developments specifically tailored for the improvement of LA sample introduction are presented. An abnormal scarcity of metal-argon polyatomic ions (MAr{sup +}) is observed during ICP-MS analysis. Evidence shows that MAr{sup +} ions are dissociated by collisions with background gas in a shockwave near the tip of the skimmer cone. Method development towards the improvement of LA-ICP-MS for environmental monitoring is described. A method is developed to trap small particles in a collodion matrix and analyze each particle individually by LA-ICP-MS.

The unique combination of magnetic properties and structural transitions exhibited by many members of the R{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} family (R = rare earths, 0 ≤ x ≤ 1) presents numerous opportunities for these materials in advanced energy transformation applications. Past research has proven that the crystal structure and magnetic ordering of the R{sub 5(Si{sub x}Ge{sub 1-x}){sub 4} compounds can be altered by temperature, magnetic field, pressure and the Si/Ge ratio. Results of this thesis study on the crystal structure of the Er{sub 5}Si{sub 4} compound have for the first time shown that the application of mechanical forces (i.e. shear stress introduced during the mechanical grinding) can also result in a structural transition from Gd{sub 5}Si{sub 4}-type orthorhombic to Gd{sub 5}Si{sub 2}Ge{sub 2}-type monoclinic. This structural transition is reversible, moving in the opposite direction when the material is subjected to low-temperature annealing at 500 ˚C. Successful future utilization of the R{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} family in novel devices depends on a fundamental understanding of the structure-property interplay on the nanoscale level, which makes a complete understanding of the microstructure of this family especially important. Past scanning electron microscopy (SEM) observation has shown that nanometer-thin plates exist in every …

A detailed study was done of the neomycin-B RNA aptamer for determining its selectivity and binding ability to both neomycin– and kanamycin-class aminoglycosides. A novel method to increase drug concentrations in cells for more efficiently killing is described. To test the method, a bacterial model system was adopted and several small RNA molecules interacting with aminoglycosides were cloned downstream of T7 RNA polymerase promoter in an expression vector. Then, the growth analysis of E. coli expressing aptamers was observed for 12-hour period. Our analysis indicated that aptamers helped to increase the intracellular concentration of aminoglycosides thereby increasing their efficacy.

We studied the effects on structural and magnetic phase transitions and the emergence of superconductivity in transition metal substituted BaFe{sub 2}As{sub 2}. We grew four series of Ba(Fe{sub 1-x}TM{sub x}){sub 2}As{sub 2} (TM=Ru, Mn, Co+Cr and Co+Mn) and characterized them by crystallographic, magnetic and transport measurements. We also subjected Ba(Fe{sub 1-x}Cr{sub x}){sub 2}As{sub 2} and Ba(Fe{sub 1-x}Co{sub x}){sub 2}As{sub 2} to heat treatment to explore what changes might be induced.

Modern calculations are becoming an essential, complementary tool to inelastic x-ray scattering studies, where x-rays are scattered inelastically to resolve meV phonons. Calculations of the inelastic structure factor for any value of Q assist in both planning the experiment and analyzing the results. Moreover, differences between the measured data and theoretical calculations help identify important new physics driving the properties of novel correlated systems. We have used such calculations to better and more e#14;ciently measure the phonon dispersion and elastic constants of several iron pnictide superconductors. This dissertation describes calculations and measurements at room temperature in the tetragonal phase of CaFe{sub 2}As{sub 2} and LaFeAsO. In both cases, spin-polarized calculations imposing the antiferromagnetic order present in the low-temperature orthorhombic phase dramatically improves the agreement between theory and experiment. This is discussed in terms of the strong antiferromagnetic correlations that are known to persist in the tetragonal phase. In addition, we discuss a relatively new approach called self-consistent ab initio lattice dynamics (SCAILD), which goes beyond the harmonic approximation to include phonon-phonon interactions and produce a temperature-dependent phonon dispersion. We used this technique to study the HCP to BCC transition in beryllium.

This work presents explorations of the potential energy surface of clusters of atoms and of the interactions between molecules. First, structures of small aluminum clusters are examined and classified as ground states, transition states, or higher-order saddle points. Subsequently, the focus shifts to dispersion-dominated π-π interactions when the potential energy surfaces of benzene, substituted benzene, and pyridine dimers are explored. Because DNA nucleotide bases can be thought of as substituted heterocycles, a natural extension of the substituted benzene and pyridine investigations is to model paired nucleotide bases. Finally, the success of the dispersion studies inspires the development of an extension to the computational method used, which will enable the dispersion energy to be modeled – and the potential energy surface explored – in additional chemical systems. The effective fragment potential (EFP) method is described, as well as various quantum mechanical methods. An ab inito quantum mechanical study of 13-atom aluminum clusters is described. EFP studies of aromatic dimers are reported in which dispersion energy makes a significant contribution to the attraction between monomers. Theory and code development toward a means of computing dispersion energy in mixed ab inito-EFP systems are described.

High temperature alloys are reviewed, focusing on current superalloys and their coatings. The synthesis, characerization, and oxidation performance of a NiAl–TiB{sub 2} composite are explained. A novel coating process for Mo–Ni–Al alloys for improved oxidation performance is examined. The cyclic oxidation performance of coated and uncoated Mo–Ni–Al alloys is discussed.

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This thesis presents the measurement of the charged current quasi-elastic (CCQE) neutrino-nucleon cross section at neutrino energies around 1 GeV. This measurement has two main physical motivations. On one hand, the neutrino-nucleon interactions at few GeV is a region where existing old data are sparse and with low statistics. The current measurement populates low energy regions with higher statistics and precision than previous experiments. On the other hand, the CCQE interaction is the most useful interaction in neutrino oscillation experiments. The CCQE channel is used to measure the initial and final neutrino fluxes in order to determine the neutrino fraction that disappeared. The neutrino oscillation experiments work at low neutrino energies, so precise measurement of CCQE interactions are essential for flux measurements. The main goal of this thesis is to measure the CCQE absolute neutrino cross section from the SciBooNE data. The SciBar Booster Neutrino Experiment (SciBooNE) is a neutrino and anti-neutrino scattering off experiment. The neutrino energy spectrum works at energies around 1 GeV. SciBooNE was running from June 8th 2007 to August 18th 2008. In that period, the experiment collected a total of 2.65 x 10²⁰ protons on target (POT). This thesis has used full data collection in …

The CP violating phase {beta}{sub s}{sup J/{psi}{phi}} is measured in decays of B{sub s}{sup 0} {yields} J/{psi}{phi}. This measurement uses 5.2 fb{sup -1} of data collected in {radical}s = 1.96 TeV p{bar p} collisions at the Fermilab Tevatron with the CDF Run-II detector. CP violation in the B{sub s}{sup 0}-{bar B}{sub s}{sup 0} system is predicted to be very small in the Standard Model. However, several theories beyond the Standard Model allow enhancements to this quantity by heavier, New Physics particles entering second order weak mixing box diagrams. Previous measurements have hinted at a deviation from the Standard Model expectation value for {beta}{sub s}{sup J/{psi}{phi}} with a significance of approximately 2{sigma}. The measurement described in this thesis uses the highest statistics sample available to date in the B{sub s}{sup 0} {yields} J/{psi}{phi} decay channel, where J/{psi} {yields} {mu}{sup +}{mu}{sup -} and {phi} {yields} K{sup +}K{sup -}. Furthermore, it contains several improvements over previous analyses, such as enhanced signal selection, fully calibrated particle ID and flavour tagging, and the inclusion of an additional decay component in the likelihood function. The added decay component considers S-wave states of KK pairs in the B{sub s}{sup 0} {yields} J/{psi} K{sup +}K{sup -} channel. The …

The MiniBooNE experiment was designed to perform a search for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations in a region of {Delta}m{sup 2} and sin{sup 2} 2{theta} very different from that allowed by standard, three-neutrino oscillations, as determined by solar and atmospheric neutrino experiments. This search was motivated by the LSND experimental observation of an excess of {bar {nu}}{sub e} events in a {bar {nu}}{sub {mu}} beam which was found compatible with two-neutrino oscillations at {Delta}m{sup 2} {approx} 1 eV{sup 2} and sin{sup 2} 2{theta} < 1%. If confirmed, such oscillation signature could be attributed to the existence of a light, mostly-sterile neutrino, containing small admixtures of weak neutrino eigenstates. In addition to a search for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations, MiniBooNE has also performed a search for {bar {nu}}{sub {mu}} {yields} {bar {nu}}{sub e} oscillations, which provides a test of the LSND two-neutrino oscillation interpretation that is independent of CP or CPT violation assumptions. This dissertation presents the MiniBooNE {nu}{sub {mu}} {yields} {nu}{sub e} and {bar {nu}}{sub {mu}} {yields} {bar {nu}}{sub e} analyses and results, with emphasis on the latter. While the neutrino search excludes the two-neutrino oscillation interpretation of LSND at 98% C.L., the antineutrino search shows an …

MINOS is a long baseline neutrino oscillation experiment, starting with a muon-neutrino beam, for the precise measurement of the atmospheric neutrino oscillation parameters |{Delta}m{sup 2}| and {theta}{sub 23}. The Near Detector measures the neutrino flux and spectra before oscillations. The beam propagates for 735 km to the Far Detector, which measures the depleted spectrum after oscillations. The depletion can be interpreted as {nu}{sub {mu}} {yields} {nu}{sub {tau}} oscillations. Subdominant {nu}{sub {mu}} {yields} {nu}{sub e} oscillations may be allowed if the mixing angle {theta}{sub 13} {ne} 0. The two detectors are functionally identical in order to cancel systematic errors when using the Near Detector data to constrain the Far Detector prediction. A crucial part of the analysis is the relative calibration between the two detectors, which is known at the 2% level. A calibration procedure to remove the time and temperature dependence of the detector response using through-going cosmic muons is presented here. Although the two-detector approach reduces the systematic uncertainties related to the neutrino flux, a cross check on the neutrino parent meson ratios is performed in this thesis. The cross sections of mesons produced in proton-carbon interactions from the NA49 experiment have been measured and the results have been …

Since early in 2003, several experiments have presented evidence for the existence of a positive strangeness baryon state of mass around 1540 MeV/c{sup 2} and width <8 MeV, the {Theta}(1540), which decays to K{sup +}n and K{sup 0}p. Such a state has minimum quark content udud{bar s} and consequently has been interpreted as the S = +1 member of the anti-decuplet of pentaquark states proposed by Diakonov et al. Subsequently, the NA49 experiment presented evidence for the S = -2 member of the anti-decuplet, the {Xi}{sub 5}(1860){sup --}, but this has yet to be observed in any other experiment. Results from the search for the production of the {Theta}(1540) memember of the anti-decuplet of pentaquark states using data from e{sup +}e{sup -} collisions obtained with the BABAR detector at the PEP-II Collider are presented. No signal is observed, and cross section limits for the {Theta}(1540) are given; these prove to be well below the cross section values for ordinary baryons of similar mass. In addition, a search has been carried out for the electroproduction of the {Theta}(1540) in the material of the BABAR detector. Event selection procedures are discussed in detail, the results of this search are presented, and are …

This dissertation discusses a data collection experiment within the Actinide Isomer Identification project (AID). The AID project is the investigation of an active interrogation technique that utilizes nuclear isomer production, with the goal of assisting in the interdiction of illicit nuclear materials. In an attempt to find and characterize isomers belonging to 235U and its fission fragments, a 232Th target was bombarded with a monoenergetic 6Li ion beam, operating at 45 MeV.

In this thesis I present two complementary strategies for probing beyond-the-Standard Model physics using data collected in e{sup +}e{sup -} collisions at lepton colliders. One strategy involves searching for effects at low energy mediated by new particles at the TeV mass scale, at which new physics is expected to manifest. Several new physics scenarios, including Supersymmetry and models with leptoquarks or compositeness, may lead to observable rates for charged lepton-flavor violating processes, which are forbidden in the Standard Model. I present a search for lepton-flavor violating decays of the {Upsilon}(3S) using data collected with the BABAR detector. This study establishes the 90% confidence level upper limits BF({Upsilon}(3S) {yields} e{tau}) < 5.0 x 10{sup -6} and BF({Upsilon}(3S) {yields} {mu}{tau}) < 4.1 x 10{sup -6} which are used to place constraints on new physics contributing to lepton-flavor violation at the TeV mass scale. An alternative strategy is to increase the collision energy above the threshold for new particles and produce them directly. I discuss research and development efforts aimed at producing a vertex tracker which achieves the physics performance required of a high energy lepton collider. A small-scale vertex tracker prototype is constructed using Silicon sensors of 50 {mu}m thickness and tested …

This thesis presents the analysis of the double differential dijet mass cross section, measured at the D0 detector in Batavia, IL, using p{bar p} collisions at a center of mass energy of {radical}s = 1.96 TeV. The dijet mass was calculated using the two highest p{sub T} jets in the event, with approximately 0.7 fb{sup -1} of data collected between 2004 and 2005. The analysis was presented in bins of dijet mass (M{sub JJ}) and rapidity (y), and extends the measurement farther in M{sub JJ} and y than any previous measurement. Corrections due to detector effects were calculated using a Monte Carlo simulation and applied to data. The errors on the measurement consist of statistical and systematic errors, of which the Jet Energy Scale was the largest. The final result was compared to next-to-leading order theory and good agreement was found. These results may be used in the determination of the proton parton distribution functions and to set limits on new physics.

The standard model of elementary particle physics (SM) predicts, besides the top-quark pair production via the strong interaction, also the electroweak production of single top-quarks [19]. Up to now, the Fermilab Tevatron proton-antiproton-collider is the only place to produce and study top quarks emerging from hadron-hadron-collisions. Top quarks were directly observed in 1995 during the Tevatron Run I at a center-of-mass energy of {radical}s = 1.8 TeV simultaneously by the CDF and D0 Collaborations via the strong production of top-quark pairs. Run II of the Tevatron data taking period started 2001 at {radical}s = 1.96 TeV after a five year upgrade of the Tevatron accelerator complex and of both experiments. One main component of its physics program is the determination of the properties of the top quark including its electroweak production. Even though Run II is still ongoing, the study of the top quark is already a successful endeavor, confirmed by dozens of publications from both Tevatron experiments. A comprehensive review of top-quark physics can be found in reference. The reasons for searching for single top-quark production are compelling. As the electroweak top-quark production proceeds via a Wtb vertex, it provides the unique opportunity of the direct measurement of the …

The production of jets in association with a Z/{gamma}* boson is an example of an important class of processes at hadron colliders, namely vector boson + jet (V + jet) production. Comparisons of measurements of this class of processes with theory predictions constitute an important, fundamental test of the Standard Model of particle physics, and of the theory of QCD in particular. While having a smaller cross section than other V +jet processes, Z/{gamma}*({yields} e{sup +}e{sup -}) + jets production, with Z/{gamma}* {yields} e{sup +}e{sup -}/{mu}{sup +}{mu}{sup -}, has a distinct experimental signature allowing for measurements characterized by low backgrounds and a direct, precise measurement of the properties of the decay products of the Z/{gamma}* boson. In this thesis, several new measurements of the properties of jets produced in association with a Z/{gamma}* boson in p{bar p} collisions at {radical}s = 1.96 TeV are presented. The cross section for Z/{gamma}*({yields} e{sup +}e{sup -}) + N jet production (N {le} 3) is measured, differential in the transverse momentum of the Nth jet in the event, normalized to the inclusive Z/{gamma}* cross section. Also, the cross section for Z/{gamma}*({yields} e{sup +}e{sup -}) + N jets (N {ge} 1) is measured, differential in …

Excitation functions for the 1n and 2n exit channels of the 208Pb(51V,xn)259-xDb reaction were measured. A maximum cross section of the 1n exit channel of 2070+1100/-760 pb was measured at an excitation energy of 16.0 +- 1.8 MeV. For the 2n exit channel, a maximum cross section of 1660+450/-370 pb was measured at 22.0 +- 1.8 MeV excitation energy. The 1n excitation function for the 209Bi(50Ti,n)258Db reaction was remeasured, resulting in a cross section of 5480+1730/1370 pb at an excitation energy of 16.0 +- 1.6 MeV. Differences in cross section maxima are discussed in terms of the fusion probability below the barrier. The extraction of niobium (Nb) and tantalum (Ta) from hydrochloric acid and mixed hydrochloric acid/lithium chloride media by bis(2-ethylhexyl) hydrogen phosphate (HDEHP) and bis(2-ethylhexyl) hydrogen phosphite (BEHP) was studied. The goal of the experiments was to find a system that demonstrates selectivity among the members of group five of the Periodic Table and is also suitable for the study of dubnium (Db, Z = 105). Experiments with niobium and tantalum were performed with carrier (10-6 M), carrier free (10-10 M) and trace (10-16 M) concentrations of metal using hydrochloric acid solution with concentrations ranging from 1 - 11 …

The WARP code is a robust electrostatic particle-in-cell simulation package used to model charged particle beams with strong space-charge forces. A fundamental operation associated with seeding detailed simulations of a beam transport channel is to generate initial conditions where the beam distribution is matched to the structure of a periodic focusing lattice. This is done by solving for periodic, matched solutions to a coupled set of ODEs called the Kapchinskij-Vladimirskij (KV) envelope equations, which describe the evolution of low-order beam moments subject to applied lattice focusing, space-charge defocusing, and thermal defocusing forces. Recently, an iterative numerical method was developed (Lund, Chilton, and Lee, Efficient computation of matched solutions to the KV envelope equations for periodic focusing lattices, Physical Review Special Topics-Accelerators and Beams 9, 064201 2006) to generate matching conditions in a highly flexible, convergent, and fail-safe manner. This method is extended and implemented in the WARP code as a Python package to vastly ease the setup of detailed simulations. In particular, the Python package accommodates any linear applied lattice focusing functions without skew coupling, and a more general set of beam parameter specifications than its predecessor. Lattice strength iteration tools were added to facilitate the implementation of problems with …

A search for the muon neutrino magnetic moment was conducted using the Mini-BooNE low energy neutrino data. The analysis was performed by analyzing the elastic scattering interactions of muon neutrinos on electrons. The analysis looked for an excess of elastic scattering events above the Standard Model prediction from which a limit on the neutrino magnetic could be set. In this thesis, we report an excess of 15.3 {+-} 6.6(stat){+-}4.1(syst) {nu}{sub {mu}e} events above the expected background. At 90% C.L., we derived a limit on the muon neutrino magnetic moment of 12.7 x 10{sup -10} {micro}{sub B}. The other analysis reported in this thesis is a measurement of charged current single pion production (CC{pi}{sup +}) to charged current quasi elastic (CCQE) interactions cross sections ratio. This measurement was performed with two different fitting algorithms and the results from both fitters are consistent with each other.

The top quark is the heaviest and most mysterious of the known elementary particles. Therefore, careful study of its production rate and other properties is of utmost importance for modern particle physics. The Tevatron is the only facility currently capable of studying top quark properties by on-shell production. Measurement of the top quark pair production cross section is one of the major goals of the Tevatron Run II physics program. It provides an excellent test of QCD at energies exceeding 100 GeV. We report on a new measurement of p{bar p} {yields} t{bar t} production at {radical} = 1.96 TeV using 350 pb{sup -1} of data collected with the D0 detector between 2002 and 2005. We focus on the final state where a W boson from one of the top quarks decays into a {tau} lepton and its associated neutrino, while the other decays into a quark-antiquark pair. We aim to select those events in which the {tau} lepton subsequently decays to one or three charged hadrons, zero or more neutral hadrons and a tau neutrino (the charge conjugate processes are implied in all of the above). The observable signature thus consists of a narrow calorimeter shower with associated track(s) …