Browsing by Subject "detector"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Design and Simulation of a Boron-loaded Neutron Spectrometer(2012-10-19) Martin, ThomasThe measurement of the distribution of kinetic energy carried by neutron particles is of interest to the health physics and radiation protection industry. Neutron particle spectral fluence is essential to the calculation of absorbed dose, equivalent dose, and other dosimetric quantities . Current methods of neutron spectrometry require either a large number of individual measurements and a priori spectral information, or complex and delicate equipment. To reduce these deficiencies, a novel neutron spectrometer, consisting of plastic scintillating fibers in a hexagonal array, was simulated via Monte Carlo. Fiber size and boron content were varied to optimize response characteristics. The results were compared to industry standard multi-sphere spectrometers. Of the geometries and materials analyzed, it was found that smaller diameter fibers with 1% loading of natural boron provide the best efficiency and energy resolution. Energy resolution was found to be similar to multi-sphere spectrometers, with the ability to differentiate on the order of ten energy fluence groups. Near isotropic angular response was traded for significantly reduced detection time and increased simplicity. Spectral analysis of individual fiber response can provide directional information based on the ratio of energy deposition by thermal neutrons to all neutrons. Future work using proton recoil spectral data from individual fibers will allow increases in energy resolution while reducing or eliminating the need for a priori spectral information.Item Mutable Detector Array Software for the Detection of Gamma Emissions in Classrooms and the Field(2012-10-19) Hearn, Gentry CharlesDetector arrays are required for many applications in health and defense. Whether searching for contraband or controlling radioactive spread after an event, a "passive" data collection strategy is a key component. This can take the form of portal monitors attached to a fixed location or a movable array, attached to a vehicle or person, which searches for abnormalities in the radiation background. The main goal of this project was to create software that would allow the digiBASE-E to be used to create arrays of gamma detection instruments and gather data over a long span of time. To take full advantage of the digiBASE-E, the software focused on the list mode capabilities of these devices. List mode attaches a timestamp to each detection event. Every particle detected can be traced to a particular point in time, and the full history of the device?s detection over the acquisition period can be reconstructed. The list mode ability of the digiBASE-E is a powerful tool for producing arrays of detectors, as a more familiar spectrum can be generated for any arbitrary section of time, even after-the-fact. The software package, called "CraneWow", was field tested at the Port of Tacoma in August of 2011. Perl scripts included as part of the package were used to partially analyze the data collected, allowing for verification of the proof-of-concept's success. The software was written in C/C++, with supplemental scripts written in Perl to facilitate processing of the data once collected. Additionally, a user manual and programming guide were written to allow easy use and maintenance of the software.Item Safeguards for Uranium Extraction (UREX) +1a Process(2011-08-08) Feener, Jessica S.As nuclear energy grows in the United States and around the world, the expansion of the nuclear fuel cycle is inevitable. All currently deployed commercial reprocessing plants are based on the Plutonium - Uranium Extraction (PUREX) process. However, this process is not implemented in the U.S. for a variety of reasons, one being that it is considered by some as a proliferation risk. The 2001 Nuclear Energy Policy report recommended that the U.S. "develop reprocessing and treatment technologies that are cleaner, more efficient, less waste-intensive, and more proliferation-resistant." The Uranium Extraction (UREX+) reprocessing technique has been developed to reach these goals. However, in order for UREX+ to be considered for commercial implementation, a safeguards approach is needed to show that a commercially sized UREX+ facility can be safeguarded to current international standards. A detailed safeguards approach for a UREX+1a reprocessing facility has been developed. The approach includes the use of nuclear material accountancy (MA), containment and surveillance (C/S) and solution monitoring (SM). Facility information was developed for a hypothesized UREX+1a plant with a throughput of 1000 Metric Tons Heavy Metal (MTHM) per year. Safeguard goals and safeguard measures to be implemented were established. Diversion and acquisition pathways were considered; however, the analysis focuses mainly on diversion paths. The detection systems used in the design have the ability to provide near real-time measurement of special fissionable material in feed, process and product streams. Advanced front-end techniques for the quantification of fissile material in spent nuclear fuel were also considered. The economic and operator costs of these systems were not considered. The analysis shows that the implementation of these techniques result in significant improvements in the ability of the safeguards system to achieve the objective of timely detection of the diversion of a significant quantity of nuclear material from the UREX+1a reprocessing facility and to provide deterrence against such diversion by early detection.