Physical Sciences and Mathematics Commons^™

Structuring A Risk-Based Bioassay Program For Uranium Usage In University Laboratories, Johnne' Talia Dawson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Bioassay programs are integral in a radiation safety program. They are used as a method of determining whether individuals working with radioactive material have been exposed and have received a resulting dose. For radionuclides that are not found in nature, determining an exposure is straightforward. However, for a naturally occurring radionuclide like uranium, it is not as straightforward to determine whether a dose is the result of an occupational exposure. The purpose of this project is to address this issue within the University of Nevada, Las Vegas’s (UNLV) bioassay program. This project consisted of two components that studied the effectiveness …

Evaluating The Risk To Ostomy Patients Working With Uranium Using The Icrp Biokinetic Model For The Gastrointestinal Tract, Sara Taylor

UNLV Theses, Dissertations, Professional Papers, and Capstones

The ICRP has published two biokinetic models providing a basis for radiation dose assessment due toradionuclides incorporated inside the gastrointestinal tract. These models are a sufficient tool to assess the committed dose equivalent for occupational exposures to workers assuming normal anatomy. The colostomy is becoming a more prevalent procedure. A colostomy permanently or temporarily bypasses a portion of colon to allow rest and healing. There are four different colostomies; ascending, transverse, descending and sigmoid and an ileostomy. As a patient’s strength returns, they can return to normal daily activities, including returning to work. Therefore, as an ostomy patient returns to …

Measurement Of Neutron Activation From A High Energy Varian Linear Accelerator, Timothy Thatcher

UNLV Theses, Dissertations, Professional Papers, and Capstones

Linear accelerators producing photons above 10 MeV may induce photonuclear reactions in high Z components of the accelerator. These liberated neutrons can then activate the structural components of the accelerator and other materials in the beam path through neutron capture reactions. The induced activity within the accelerator may contribute to additional dose to both patients and personnel. This project seeks to determine the total activity and activity per activated isotope following irradiation from a Varian medical linear accelerator at energies above 10 MeV. A Varian 21iX accelerator was used to irradiate a 30 cm x 30 cm x 20 cm …

Neutron-Gamma Discrimination In Elpasolite Scintillator Detector, Brittany Morgan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Existing nuclear stockpiles and weapons-making capabilities imperil the global community. Current nonproliferation efforts involve the research and development of newer, more efficient detection systems that can be deployed for the interdiction and monitoring of special nuclear materials (SNM). Spontaneous and induced fission events in SNM produce neutrons and gamma rays, which can be detected and analyzed, in particular, using scintillator detectors. Various electronic data acquisition systems and data analysis methods have been employed to record and characterize neutron and photon signatures. The goal of this thesis is to develop a new method of discrimination between neutrons and photons in the …

Mcnp6 Computational-Based Sensitivity Propagation Analysis Of Continuous Neutron Cross-Sections Using The Godiva (Hmf-001) And The Godiver (Hmf-004) Benchmark Criticality Study Cases, Lawrence James Lakeotes

UNLV Theses, Dissertations, Professional Papers, and Capstones

There has been a reduction in funding for theoretical and applied research for improving the nation's database of continuous neutron cross-sections at BNL-NNDC. From 1940 through the late 1980s, research and applied development produced volumes of reliable neutron continuous cross-sections for many isotopes. Currently, the cross-section work has been mainly computational. The focus of this research is mainly centered on the requirements for improving thermal cross-sections to support reactor operations and fuel storage. The research efforts will also helpfully aid in the fast fission spectrum in order to support fast reactor designs for improving safety analysis and feedback coefficients.

This …