In order to understand better the defect structure and dynamics associated
with lower valent dopants complexed with native defects in group IV oxides, In/Cd
perturbed angular correlation spectroscopy was performed in ceria and zirconia. Examining
the orientation symmetry axis of defects in ceria single crystals at low temperature
has allowed...
The results of a review of six decades of existing literature for 50% lethal dose data across a range of phyla are presented. The collected 50% lethal dose data is limited to adult organisms subjected to acute doses of gamma radiation. The data collected is examined to determine whether useful...
The process of de-excitation of the actinides is a very important question in both pure and applied science. In this dissertation the process was studied using the neutrons emitted in coincidence with fission induced by the bombardment of ²³⁸U with 14.85 MeV deuterons. Neutrons can be emitted at multiple stages...
The purpose of this study is to investigate the relative performance of compact ionization chambers as it changes based on the speed of detector motion and collection volume. To quantify changes, multiple scans were made with each of a selection of compact chambers and repeated varying detector speed. Each scan...
BACKGROUND: The frequency of C-arm fluoroscopy procedures is increasing and it has become prudent to increase the awareness of patient radiation exposure to minimize patient risk. There is a strong potential for variability in patient exposure levels and a need for minimizing unnecessary exposure. The variability in C-arm fluoroscopy can...
Multi-layer optically coupled scintillation based radiation detectors, known as phoswich detectors, have rapidly evolved in recent years. During the same time, digital signal processing has improved radiation discrimination accuracy and enhanced reliability, while reducing complexity and size of traditional analog signal processing methods. A new generation of high-speed radiation detectors...
A hybrid Quasi-diffusion/Monte Carlo Method for solving multigroup criticality problems in slab geometry was investigated. Analog Monte Carlo was used to calculate functionals (Eddington Factors) that were then used in solution of the quasi-diffusion equations. The hybrid method was shown to accurately and precisely predict the k-eigenvalue and fission source...
Coal power is the prominent source of energy in the United States (U.S.) and around the world. The byproducts of coal power contain many of the same radioactive nuclides that are found in the local environment just in higher concentrations. With so much of this ash being stockpiled, the amount...
Since the 1990s, researchers around the world have been creating antineutrino detectors for monitoring power reactors. These detectors have been deployed at light water reactors and are able to determine power levels and burn up throughout a fuel cycle. This technology could allow the IAEA to monitor LWRs remotely and...
In this work, Neutron Depth Profiling (NDP) analysis capability has been added to the Oregon State University TRIGA® Reactor Prompt Gamma Neutron Activation Analysis Facility (PGNAA). This system has been implemented with an advanced digital spectroscopy system and is capable of rise time pulse shape analysis as well as coincidence...
The Run-Ahead Predictive Simulation Software (RAPSS) is an architecture designed for faster-than-real-time decision support for operators of complex networks. To enable further development of the RAPSS methodology, the necessary proof of principle is illustrated in two applications: decision support for shift technical advisors in nuclear power plant control rooms (RAPSS-STA),...
Monte Carlo (MC) algorithms are widely accepted as the most accurate method to calculate dose in a patient geometry. For this work the EGSnrc MC code was used as a benchmark for the identification of dose calculation errors produced by the widely implemented analytical anisotropic algorithm (AAA). By correlating the...
The need for cheap reliable energy, while simultaneously avoiding uranium supply constraints makes uranium carbide (UC) fueled Gas Fast Reactors offer an attractive nuclear reactor design. In order to qualify the fuel, an enhanced understanding of the behavior of uranium carbide during operation is paramount. Due to a reduced re-solution...
Several radioxenon isotopes (¹³¹ᵐXe, ¹³³Xe, ¹³³ᵐXe, ¹³⁵Xe) are characteristic byproducts of nuclear explosions, and due to their chemically nonreactive nature can easily escape from tests occurring underground and enter the atmosphere. It has been shown that by utilizing beta-gamma coincidence techniques, the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO) can...
The International Atomic Energy Agency (IAEA) is the leading organization for monitoring nuclear facilities worldwide, and the Agency’s methods are constantly developing and improving in an effort to more effectively safeguard nuclear material. As such, the IAEA addresses near and long term risks in order to advance the capabilities of...
The lens dose equivalent (LDE) is a regulatory limit set to protect radiation workers. Current methods for estimating the LDE are specific to beam sources in a vacuum and require interpolating data from tables. A new set of deterministic equations for photon and electron point sources has been developed. These...