Nuclear Commons^™

Finding Nuclear Drip Lines And Studying Two Proton Emission, Alexander Matthew Perhac

University of Tennessee Honors Thesis Projects

No abstract provided.

Evaluation Of Tagging Techniques Gamma-Decay Probabilities Using The Surrogate Method, Timothy Lee Reed

Masters Theses

A detailed analysis of the statistical and discrete [gamma]-decay tagging techniques was conducted using the absolute surrogate and surrogate ratio method (SRM) to obtain the 92Mo(n,[gamma]) cross section in an equivalent neutron energy range of 80 to 880 keV. Excited 93Mo and 95Mo nuclei were populated using (d,p) reactions on 92Mo and 94Mo targets, respectively. The absolute surrogate 92Mo(n,[gamma]) cross sections disagreed with evaluated neutron capture cross section data by as much as a factor of 4 using the statistical tagging approach, whereas the discrete [gamma]-decay tag absolute surrogate cross section disagreed with ...

Testing A Novel Technique To Improve Aluminum-26 Accelerator Mass Spectrometry Measurements For Earth Science Applications, Meghan Sarah Janzen

Masters Theses

The measurement of cosmogenic ²⁶Al [aluminum-26] in geological samples by accelerator mass spectrometry (AMS) is typically conducted on Al₂O₃ [aluminum oxide] targets. However, Al₂O₃ is not an ideal source material because it does not form a prolific beam of Al^- [negative atomic aluminum ions] required for measuring low-levels of ²⁶Al. This thesis presents the performance of AlN [aluminum nitride], AlF₃ [aluminum fluoride] and mixed AlN + Al₂O₃ as novel alternative source materials for the analysis of ²⁶Al. A negative ion cesium sputtering source at the Holifield Radioactive Ion ...

Contributions To Background Reduction And Computer Simulations For Cuore & Cuore-0, Ivo J. Plamenac

Physics

CUORE and CUORE-0 aim to observe neutrinoless double beta decay in ¹³⁰Te; observing such this particular decay would substantiate the Majorana model for the neutrino and expand our current understanding of particle physics. This report will provide an overview of the Standard Model, our current framework for particle interactions, as well as the technical details of the CUORE experiment. Over the summers of 2010 and 2011, I contributed to the efforts of the CUORE collaboration by assisting in aspects such as background reduction, and explored detector behavior using computer simulations.

Density Functional Theory And The Calculation Of Tcmg2O4 Spinel Lattice Parameters, Jon Karlo Macias

Physics

The cohesive energy, lattice constant and bulk modulus of two simple HCP crystal structures of magnesium and technetium were calculated using the vienna ab initio simulation package (VASP) which is based on density functional theory (DFT). The same properties were determined for TcMg₂O₄ spinel. The theoretical results of the lattice constant of the pure crystals were compared to experimental results and found to be in excellent agreement with a difference of less than 2%. The results for the lattice constant of the TcMg₂O₄ spinel were found to be in excellent agreement as well with ...

Superfluidity In Neutron Stars, Samuel J. Witte

Undergraduate Theses—Unrestricted

Nucleon pairing is studied with specific considerations directed toward the possible influence on neutron star cooling. We present an in-depth analysis of BCS theory using realistic nuclear potentials and consider the impact short-range correlations can have on the gap. Gap calculations are incorporated into neutron star cooling simulations and the significance of the 3P2 −3F2 channel in various hadronic cooling models is closely examined. An analysis of the 1S0 gap in neutron matter suggests short-range correlations can drastically alter the magnitude, density range, and temperature dependence of the gap. While the newly constructed 1S0 gap does not significantly alter the ...

Microscopic Description Of Nuclear Fission At Finite Temperature, Jordan David Mcdonnell

Doctoral Dissertations

While a predictive, microscopic theory of nuclear fission has been elusive, advances in computational techniques and in our understanding of nuclear structure are allowing us to make significant progress. Through nuclear energy density functional theory, we study the fission of thorium and uranium isotopes in detail. These nuclides have been thought to possess hyperdeformed isomers in the third minima of their potential energy surfaces, but microscopic theories tend to estimate either shallow or non- existent third minima in these nuclei. We seek an explanation in terms of neutron shell effects. We study how the fission pathways, the symmetry, and the ...

Secondary Light Particle Data Base Development Using A Thermodynamic Coalescence Model, Mahmoud Pourarsalan

Doctoral Dissertations

ABSTRACT

As heavy ions are transported through shielding and interact with shielding materials accurate values of total, elastic scattering, reactions cross sections and angular distributions of the emitted nucleons, light high energy particles such as deuteron, triton, helion, alpha particles and other heavy ions are required in order to design appropriate and adequate shielding to protect the human crews and instruments from ionizing radiations during long duration space missions. Double-differential (energy and angle) light energetic particle production cross sections must be known for ion energies from tens of MeV/nucleon to tens of GeV/nucleon for all emitted light energetic ...

Higher-Order Corrections In Effective Theory Of Deformed Nuclei, Jialin Zhang

Masters Theses

The low-energy excitation bands of open-shell heavy nuclei have been accounted for by collective motion of the constituting nucleons. Macroscopically, heavy nuclei can be looked upon as deformed rotors undergoing surface vibration and rotation. Traditionally, deformed nuclei are described within the Bohr-Mottelson geometric model or the interacting boson model. An effective theory that exploits spontaneous symmetry breaking has recently been developed for axially deformed nuclei. It describes the rotational and vibrational degrees of freedom in terms of Nambu-Goldstone bosons and quadrupole phonons respectively, with a power counting based on their different energy scales. A systematic way to construct the rotationally ...

Hrc Enews — 2012 Summer, Megan M. Iudice

Publications (HRC)

This issue contains staff accomplishments and announcements, event listings, and a "new faces" listing for new staff, affiliates, and researchers.

Significance Of Ion Induced Luminescence For Radiation Induced Bystander Effects, Syed Bilal Ahmad

Medical Physics & Applied Radiation Sciences Publications

Radiation induced bystander effects have given the cancer risk analysis a whole new paradigm. However the actual mechanism involved in producing the effects is still not clear. The basic bystander signal is assumed to be a biological signal. In this study we proposed and tried to quantify the presence of a physical signal in the form of electromagnetic radiation that can trigger a biological response in the bystander cells. In bystander effect studies where the cells are exposed to very low fluence of charged particles there could be several regions that can produce electromagnetic radiation due to the process of ...

Simulation Of Time-Dependent Neutron Populations For Reactor Physics Applications Using The Geant4 Monte Carlo Toolkit, Liam F. Russell

Open Access Dissertations and Theses

When the material or geometry of a reactor varies with time, the neutron flux will respond in the form of a reactor transient. These transients can occur during normal operations when control rods are moved or the reactor is refuelled (CANDU). During a reactor accident, the transient response is especially important because the reactor properties vary quickly with large amplitudes. Therefore, better understanding these conditions allows for improved identification, prevention and mitigation of reactor transients. However, current nuclear simulation codes are generally limited in their ability to model transient behaviour.

The NStable code was created to model time-dependent neutron populations ...

The Atomic Testing Museum, Las Vegas, Nevada, Angela Moor

Psi Sigma Siren

The Atomic Testing Museum attempts to interpret history that has barely ended. The controversy and emotion that surround nuclear weapons remain fresh in many Americans‘ minds. The museum must walk a careful line when interpreting such recent history. Few other American history museums offer interpretation of the Cold War, and certainly, the Atomic Testing Museum stands as the sole museum dedicated to atomic testing. As years go by, and the memory of the mushroom cloud floating on the Nevada desert fades, the museum may feel more comfortable in providing a balanced narrative on atomic testing. For now, as retired "Cold ...

Mri-Based Attenuation Correction In Emission Computed Tomography, Harry R. Marshall

Electronic Thesis and Dissertation Repository

The hybridization of magnetic resonance imaging (MRI) with positron emission tomography (PET) or single photon emission computed tomography (SPECT) enables the collection of an assortment of biological data in spatial and temporal register. However, both PET and SPECT are subject to photon attenuation, a process that degrades image quality and precludes quantification. To correct for the effects of attenuation, the spatial distribution of linear attenuation coefficients (μ-coefficients) within and about the patient must be available. Unfortunately, extracting μ-coefficients from MRI is non-trivial. In this thesis, I explore the problem of MRI-based attenuation correction (AC) in emission tomography.

In particular, I ...