Nuclear Commons^™

Particle Swarm Optimization For Critical Experiment Design, Cole Michael Kostelac

Masters Theses

“Critical experiments are used by nuclear data evaluators and criticality safety engineers to validate nuclear data and computational methods. Many of these experiments are designed to maximize the sensitivity to a certain nuclide-reaction pair in an energy range of interest. Traditionally, a parameter sweep is conducted over a set of experimental variables to find a configuration that is critical and maximally sensitive. As additional variables are added, the total number of configurations increases exponentially and quickly becomes prohibitively computationally expensive to calculate, especially using Monte Carlo methods.

This work presents the development of a particle swarm optimization algorithm to design …

Customized Multi-Group Cross Section Generation With Njoy For Discrete Ordinates Computed Tomography And Radiography Simulation, Steven Michael Wagstaff

Masters Theses

"The purpose of this work was to explore the creation of photoatomic multi-group cross section libraries to be used with a software package DOCTORS (Discrete Ordinates Computed TOmography and Radiography Simulator). This software solves the linear Boltzmann equation using the discrete ordinates method [1]. To create these libraries, NJOY2016 was used, creating both fine and broad energy multi-group cross section files. The cross section's accuracy was tested against an equivalent Monte Carlo simulation using MCNP6.

Two simulation geometries were used. The first, a cylindrical water phantom with a single source projection placed in front, simulating an X-ray radiography. The second …

Modulated Photothermal Radiometry: Detector Sensitivity Study And Experimental Setup, Jessica Nicole Seals

Masters Theses

"This thesis outlines the development of a system used for determining the surface thermal diffusivity of both non-irradiated and irradiated materials. The motivation for this work is to establish a modulated photothermal radiometry (PTR) system on the campus of Missouri University of Science and Technology. One of the main efforts described in this thesis is the design and construction of the physical apparatus. Along the way, it was necessary to perform a detailed sensitivity analysis of the system to determine whether the expected signal emitted from the sample falls within the bounds of detectivity for the HgCdTe (MCT) detector used …

A Study Of The Potential Applications Of Am241, And Determining The Feasibility Of Using Gamma Spectroscopy For Future Physical Validation, Eric A. Feissle

Masters Theses

“Am241 is typically produced via Pu241 decay in a uranium fueled reactor. Presence of Am241 can be used as the age estimation tool for spent fuel, which is a focus of this thesis along with the interest of the measurement and the ratio of production rates of Am241’s activation products; Americium-242 and its first excited state of Americium-242m. MCNP models of the core and BEGe 3825 detector were built. These models were compared with established and physical measurements of gamma/x-ray standards that were available at the reactor. Thermal fluxes at 200 kW for potential foils centered in the source holder …

Attenuation Properties Of Cement Composites: Experimental Measurements And Monte Carlo Calculations, Raul Florez

Masters Theses

"Developing new cement based materials with excellent mechanical and attenuation properties is critically important for both medical and nuclear power industries. Concrete continues to be the primary choice material for the shielding of gamma and neutron radiation in facilities such as nuclear reactors, nuclear waste repositories, spent nuclear fuel pools, heavy particle radiotherapy rooms, particles accelerators, among others. The purpose of this research was to manufacture cement pastes modified with magnetite and samarium oxide and evaluate the feasibility of utilizing them for shielding of gamma and neutron radiation. Two different experiments were conducted to accomplish these goals. In the first …

A Large Scintillation Detector For Nuclear Physics Experiments At Indiana University Cyclotron Facility, Apurva Pathak

Masters Theses

A new, large, scintillation detector, called the "K" detector has been designed and built for use in a series of nuclear physics experiments being performed at the Indiana University Cyclotron Facility (IUCF). This project describes the design, construction and testing of this scintillation detector. The K detector was designed to augment an existing detector stack at IUCF, and will serve to increase the energy range of previous studies of neutral pion production in proton-proton collisions near threshold. The test data for the current project came from a proton-proton scattering experiment, during which several runs were carried out between the bombarding …

Eta Photoproduction Via 2H(Γη)2H*, Yan Zhang

Masters Theses

The reaction H(γη)²H^* is studied using the impulse approximation. A recent fit to the H(γη)²H^* elementary amplitude is employed in the calculation. The n-p final state is described by Reid's soft core potentials. The calculation shows very different cross sections for the final isospin 0 and isospin 1 break-up channels. The S₁₁ resonance is demonstrated to dominate the eta cross sections in the 740 MeV photon laboratory energy region. Fermi motion in the deuteron does not significantly spread the effect of the S₁₁ . All these results demonstrate that the reaction H(γη) …

A Valence Quark Model, Tony A. Forest

Masters Theses

A quark model of the baryons has been developed for calculating properties of nucleons which can be useful in nuclear interactions. A Hamiltonian, motivated by QCD, was diagonalized in a harmonic oscillator basis. In addition to predicting the proton charge radius and Delta-Nucleon mass difference, this work also yields a value of the axial vector coupling constant which compares well with experiment. Electric and magnetic form factors represent the major success of this model. The electromagnetic transitions predicted by this model compete well with other models but are not able to reproduce experimental results completely. The advantage of this model …

Calculation Of Electron Scattering For 4He In A Continuum Shell Model, Ming Yu

Masters Theses

Calculations for the electroexcitation of the ⁴He, O+ state have been performed within the context of recoil corrected continuum shell model. Approximations previously employed for inelastic scattering with the recoil corrected continuum shell model are eliminated in the work. The O+ state exhausts only 10% of the energy weighted sum rule and previous shell model calculations for the excitation of this state produce about ten times too much strength. This difficulty is alleviated by the use translationally invariant wave functions and the application of continuum boundary conditions for this particle unbound state. The structure of the O+ state is …

Relativistic And Non-Relativistic Nuclear Charge Form Factors, Tao Wang

Masters Theses

This thesis presents an examination that the two nuclear charge form factors, relativistic and non-relativistic, are equivalent approximately in an appreciable range. The relativistic one is contributed by both vector charge density and tensor charge density. And the non-relativistic charge form factor is contributed by the nuclear densities from experimental electron scattering cross section, these densities are fundamental to much of nuclear structure physics.

The Dirac equation is used to calculate the vector charge density and tensor density, because the charge density from the analysis of the experimental data may be compared with proton charge densities obtained from various models …

Recoil Corrected Continuum Shell Model Form Factor Calculations For 4He(E,E’)4He(0+), Jiang Yu

Masters Theses

Charge form factor calculations for the electroexcitation of the ⁴He, 0⁺ state have been performed within the context of the recoil corrected continuum shell model. A pure Os⁴ ground state structure is assumed and full internal coordinate recoil corrections are made. The result is compared with available data. It is demonstrated that the 0+ state may be described in a 1p -1h shell model context. Inclusion of nsOs^-1 ground state correlations is suggested for further research.

Hypernuclear Photoproduction Via (Γ,K*), Kimberly Ann Hodgkinson

Masters Theses

The nuclear (γ,K^*) reaction is studied using plane wave impulse approximation (PWIA) and a distorted wave impulse approximation (DWIA), which includes full Coulomb and optical distortions. The model and calculations for each model are presented. For ¹²C(γ K^*)¹²B, the two approximation methods are compared at 2 energies: 1.47 Gev/c and 1.84GeV/c. ²⁰⁸Pb(γ, K^*)²⁰⁸ i s a lso examined. Distortion effects are found to greatly alter the magnitude of the cross sections, but the shape of the angular distributions remains. the same. Conclusions suggest further study.

A Study Of The Direct Capture Process Of Protons By 27Al, Rozana Hussain

Masters Theses

An experimental investigation of the 27Al(p,γ)²⁸Si reaction was made for protons in the energy range 550- to 1785-keV and at angles of 0, 20, 55, 90 and 118 degrees. Four angular distributions at E_p = 845-, 1055-, 1135-, and 1618-keV were selected for detailed study. These angular distributions were fit with theoretical calculations employing a directcapture model. These fits permitted the extraction of spectroscopic factors for the population of the first excited-state in ²⁸Si by proton transfer.

Determination Of Phenomenological Optical Model Parameters For Neutrons On 208Pb From 4 To 150 Mev, Randy L. Schutt

Masters Theses

Phenomenological o p tic a l model parameters for neutrons incident on ²⁰⁸Pb have been determined for neutron energies from 4 to 150 MeV using the code SNOOPY-8. Neutron total cross sections from 4 to 150 MeV and angular distributions for elastic scattering from 13.5 to 40.0 MeV were utilized. Analyses of total and differential cross sections were performed at a number of energies to determine energy dependent expressions for the real strengths of the central potential, imaginary surface potential, and imaginary volume potential. These energy dependent expressions for V, W_d, and W_S were found to …

A Study Of Classical Elastic Scattering For Heavy-Ion Nuclear Reactions, John C. Orrison

Masters Theses

Numerical computer programs were developed to calculate the classical elastic scattering orbits, deflection functions and differential scattering cross-sections for a heavy-ion nuclear reaction model.

Critical points of the deflection functions and differential scattering cross-sections were examined.

Semiclassical modifications were developed for future study to account for the phase relation between independent orbits that lead to the same scattering direction.

Calculations For The Excitation Of High Spin Natural Parity States In Hypernuclei Via (Π+, K+), Yizhang Ho

Masters Theses

No abstract provided.

Microscopic Optical Potentials, Michael R. Sloothaak

Masters Theses

No abstract provided.

Medium Modified Proton Densities Deduced From Electron Scattering Experiments, Steven Paul Deryke

Masters Theses

Recently two fundamental problems in nuclear physics have been resolved by applying the concept of nucleon size increases over that of free nucleons. These successes have encouraged the use of medium-modified proton densities to explain the differences between Hartree-Fock calculations and experimental charge densities. These differences constituted a long standing problem in nuclear physics.

The covariant soliton model of density dependent nucleon form factors was employed to explain these differences. This model predicts a non-linear relationship between point proton densities and charge densities. This work was able to provide a self-consistent proton density for ²⁰⁸Pb by inverting this relationship. …

The Pauli Operator Correction In The Effective Λn Interaction, Jaleh Owliaei

Masters Theses

Hypernuclear structure calculations performed for ⁶_ΛLi, ⁷_ΛLi, and ¹⁶_Λ0 have reproduced the 1_Λ=1 levels inferred from the recent (k, Π) reactions. However the 1_Λ=0, groundstate of ¹⁶_Λ0 is overbound by 6 MeV in these calculations, indicating a density dependence in the effective ΛN interaction in the interior of the heavier system. In this work corrections to the ¹⁶_Λ0 effective interaction are introduced in terms of a Brueckner-Goldstone G-matrix with a modified Pauli operator. The G-matrix of ¹⁶_Λ0 derived from that of ⁶_ΛLi …

The Neutron Total Cross Section Of 208Pb, Lawrence J. Satkowiak

Masters Theses

No abstract provided.

Generalization Of The Form Of The T Matrix Operator Of Non-Relativistic Scattering Theory, Francis Leone

Masters Theses

No abstract provided.

Spin-Flip In 12C (P,P') 12C Near The 9.14 Mev Doublet, John Ambani Muhanji

Masters Theses

No abstract provided.

Measurement Of Neutron Differential Cross Sections Using The Associated Particle Method, Gary Eugene Rochau

Masters Theses

No abstract provided.

Spectroscopic Determinations Using Resonance Spin-Flip In 12C (P,P1) 12C And 50Ti (P,P1) 50Ti, Lee Robert Baumann

Masters Theses

No abstract provided.

Angular Distributions Of Protons From The 28Si(∝,P)31P Reaction, Susan Mary Allen

Masters Theses

No abstract provided.

Properties Of 1‾ Excited States Of Complex Nuclei, Carlos Ignacio Calle

Masters Theses

No abstract provided.

Effects Of Nuclear Deformation On Neutron Total Cross Sections, Dennis Gilbert Blondin

Masters Theses

No abstract provided.

The Analysis Of Three Narrow Resonances Observed In Protons On Oxygen-16, Benjamin Y. J. Tan

Masters Theses

No abstract provided.

Calculations Of Nuclear Structure Using Isospin Formalism, Roger A. Cook

Masters Theses

No abstract provided.

Scattering Spin 1/2 Particles By Nuclei, Pui-Wah Cheng

Masters Theses

No abstract provided.