Detection and simulation of delayed gamma-rays from photofission

Update Item Information
Publication Type thesis
School or College College of Engineering
Department Civil & Environmental Engineering
Author Kavouras, John George
Title Detection and simulation of delayed gamma-rays from photofission
Date 2014-05
Description Discrimination of delayed emissions from photonuclear fission events provides the necessary information for the detection of nuclear materials. The time and energy characteristics of signature signals provide unique fingerprints which can be used for the identification and quantification of fissionable isotopes using γ-ray spectroscopy. This investigation explores measurement results of β-delayed γ-rays from photofission events. During the experiment, spectroscopy measurements were taken using two high-purity germanium detectors while three separate signal processing units were used for data acquisition. Interrogation of 238U, 239Pu, and 232Th was performed using a 22 MeV pulsed bremsstrahlung photon beam. Fission fragments with energies above 3 MeV were identified as delayed-fission γ-rays unique to the fissionable materials. A numerical model of the experimental setup is also proposed as part of this research. This model is based on the Monte Carlo radiation transport code MCNPX. The data from the experiment were used to validate the numerical models. Additionally, photonuclear data libraries were tested in the numerical model for consistency and accuracy. The numerical results showed a good agreement with the experimental data, specifically the comparison of 238U. Discrepancies between the numerical results and experimental data of 232Th were observed. A new photonuclear data library from TENDL/ACE was then implemented for 232Th and the numerical results were improved. One of the main contributions of this work is the development of a reliable computational model that gives almost the same results that could be performed on a physical experimentation as a less expensive option to examine the factors that could fall behind the spectroscopy measurements.
Type Text
Publisher University of Utah
Subject Delayed; Detection; Gamma; MCNP; Photofission; Simulation
Dissertation Institution University of Utah
Dissertation Name Master of Science
Language eng
Rights Management Copyright © John George Kavouras 2014
Format Medium application/pdf
Format Extent 1,674,713 Bytes
Identifier etd3/id/2964
ARK ark:/87278/s6kt00sc
Setname ir_etd
ID 196533
Reference URL