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Full-Text Articles in Nuclear Engineering
A Datacentric Algorithm For Gamma-Ray Radiation Anomaly Detection In Unknown Background Environments, James M. Ghawaly Jr
A Datacentric Algorithm For Gamma-Ray Radiation Anomaly Detection In Unknown Background Environments, James M. Ghawaly Jr
Doctoral Dissertations
The detection of anomalous radioactive sources in environments characterized by a high level of variation in the background radiation is a challenging problem in nuclear security. A variety of natural and artificial sources contribute to background radiation dynamics including variations in the absolute and relative concentrations of naturally occurring radioisotopes in different materials, the wet-deposition of $^{222}$Rn daughters during precipitation, and background suppression due to physical objects in the detector scene called ``clutter." This dissertation presents a new datacentric algorithm for radiation anomaly detection in dynamic background environments. The algorithm is based on a custom deep neural autoencoder architecture called …
A Generalized Method For Fissile Material Characterization Using Short-Lived Fission Product Gamma Spectroscopy, Justin Richard Knowles
A Generalized Method For Fissile Material Characterization Using Short-Lived Fission Product Gamma Spectroscopy, Justin Richard Knowles
Doctoral Dissertations
Characterizing the fissile content of nuclear materials is of particular interest to the safeguards and nuclear forensics communities. Short-lived fission product gamma spectroscopy offers a significant reduction in analysis time and detection limits when compared to traditional non-destructive assay measurements. Through this work, a fully generalizable method that can be applied to variations in fissile compositions and neutron spectra was developed for the modeling and measurement of short-lived fission product gamma-rays. This method uses a 238-group neutron flux that was characterized for two pneumatic tube positions in the High Flux Isotope Reactor using flux monitor irradiations. This flux spectrum was …
Characterization Of Mechanically Cooled High Purity Germanium (Hpge) Detectors At Elevated Temperatures, Joseph Benjamin Mccabe
Characterization Of Mechanically Cooled High Purity Germanium (Hpge) Detectors At Elevated Temperatures, Joseph Benjamin Mccabe
Doctoral Dissertations
High resolution gamma spectroscopy is a tool used in nuclear security applications due to its achievable energy resolution and associated ability to identify special nuclear material. This identification ability is achieved by identifying the characteristic gamma-rays of a material. The challenges that have confronted industry concerning the use of hand-held high purity germanium (HPGe) in homeland security applications have centered on weight, geometry, and cool-down time. Typical liquid nitrogen cooled detectors ranging in size from 10% to 150% detectors will cool down sufficiently within 2-6 hours of filling. The cool-down time achieved in this research ranges from 45 min on …