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Full-Text Articles in Physics

Fabrication, Measurements, And Modeling Of Semiconductor Radiation Detectors For Imaging And Detector Response Functions, Corey David Ahl May 2023

Fabrication, Measurements, And Modeling Of Semiconductor Radiation Detectors For Imaging And Detector Response Functions, Corey David Ahl

Doctoral Dissertations

In the first part of this dissertation, we cover the development of a diamond semiconductor alpha-tagging sensor for associated particle imaging to solve challenges with currently employed scintillators. The alpha-tagging sensor is a double-sided strip detector made from polycrystalline CVD diamond. The performance goals of the alpha-tagging sensor are 700-picosecond timing resolution and 0.5 mm spatial resolution. A literature review summarizes the methodology, goals, and challenges in associated particle imaging. The history and current state of alpha-tagging sensors, followed by the properties of diamond semiconductors are discussed to close the literature review. The materials and methods used to calibrate the …


Nondestructive Evaluation Of 3d Printed, Extruded, And Natural Polymer Structures Using Terahertz Spectroscopy And Imaging, Alexander T. Clark May 2022

Nondestructive Evaluation Of 3d Printed, Extruded, And Natural Polymer Structures Using Terahertz Spectroscopy And Imaging, Alexander T. Clark

Dissertations

Terahertz (THz) spectroscopy and imaging are considered for the nondestructive evaluation (NDE) of various three-dimensional (3D) printed, extruded, and natural polymer structures. THz radiation is the prime candidate for many NDE challenges due to the added benefits of safety, increased contrast and depth resolution, and optical characteristic visualization when compared to other techniques. THz imaging, using a wide bandwidth pulse-based system, can evaluate the external and internal structure of most nonconductive and nonpolar materials without any permanent effects. NDE images can be created based on THz pulse attributes or a material’s spectroscopic characteristics such as refractive index, attenuation coefficient, or …


Nuclear Magnetic Resonance Studies Of Electrode And Electrolyte Materials For Li-Ion Batteries, Lisa Cirrincione Sep 2017

Nuclear Magnetic Resonance Studies Of Electrode And Electrolyte Materials For Li-Ion Batteries, Lisa Cirrincione

Dissertations, Theses, and Capstone Projects

In this thesis, Nuclear Magnetic Resonance (NMR) spectroscopic techniques are used to study lithium electrode and electrolyte materials for advanced rechargeable lithium ion batteries. Three projects are described in this thesis. The first involves 23Na and 37Al static and magic angle spinning NMR studies of NaAlH4/C anode materials for advanced rechargeable batteries. The second project is a study of paramagnetic lithium transition-metal phosphate cathode materials for Li-ion batteries, where 7Li, and 31P single crystal NMR was used in order to obtain detailed information on the local electronic and magnetic environments. The third project investigates …


Mueller Matrix Spectroscopic Ellipsometry Of Multiferroics, Roman Basistyy Jan 2015

Mueller Matrix Spectroscopic Ellipsometry Of Multiferroics, Roman Basistyy

Dissertations

Multiferroics, materials which possess several ferroic orders, are the focus of research in recent years. Among these materials are oxide crystals, such as, for example, RMnO3, RMn2O5, R3Fe5O12, where R stands for rare earth ions. The most fascinating physics occurs when magnon-lattice coupling reveals itself in the far-IR spectra of multiferroics. The expected optical behavior puts multiferroics into a more general category of bi-anisotropic materials, the properties of which could be only described using anisotropic dielectric ε(ω), magnetic μ(ω), and …


Study Of Propagation And Detection Methods Of Terahertz Radiation For Spectroscopy And Imaging, Aparajita Bandyopadhyay May 2006

Study Of Propagation And Detection Methods Of Terahertz Radiation For Spectroscopy And Imaging, Aparajita Bandyopadhyay

Dissertations

The applications of terahertz (THz, 1 THz is 1012 cycles per second or 300 pm in wavelength) radiation are rapidly expanding. In particular, THz imaging is emerging as a powerful technique to spatially map a wide variety of objects with spectral features which are present for many materials in THz region. Objects buried within dielectric structures can also be imaged due to the transparency of most dielectrics in this regime. Unfortunately, the image quality in such applications is inherently influenced by the scattering introduced by the sample inhomogeneities and by the presence of barriers that reduces both the transmitted power …