Real Time Temporal Spectroscopy for Characterizing Special Nuclear Material Public Deposited


Attribute NameValues
Abstract or Summary
  • Characterizing special nuclear material (SNM) is critical for nuclear security and non-proliferation. Temporal spectroscopy is a novel and efficient method for characterizing relative material content of special nuclear material. Fission products produced by SNM after being irradiated by a thermal neutron beam can have different half-lives, but can contribute to a similar gamma-ray energy. Temporal spectroscopy analyzes the temporal characteristics of this gamma-ray energy and quantifies the relative mass of 235U and 239Pu. Real time temporal spectroscopy was successfully conducted at Oregon State University’s TRIGA reactor using a FPGA. A digital to analog converter board (DPP8), developed at OSU, was connected in tandem with the FPGA board to conduct all digital pulse processing needs. Temporal measurements were done by shuttling a sample of between a thermal neutron beam and a HPGe detector. The FPGA provides complete control of the solenoids to shuttle the sample and is also capable of tracking the location of the sample by continuously monitoring optical sensors. A ‘listogram’ module was created to capture temporal slices of a gamma spectrum when the sample was in front of the detector. All digital pulse processing occurs in the FPGA in real-time to maximize flexibility. Pure samples of natural silver and dysprosium powders were measured to develop reference temporal spectrum. Mixtures of silver and dysprosium, varying from 25% silver/75% dysprosium to 75% silver/25% dysprosium, were measured using the ‘listogram’ module implemented in the FPGA. Relative silver concentrations were estimated to be 62.5% +/- 1.9 % with the actual silver content of 68.2 %.
Resource Type
Date Created
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Committee Member
Academic Affiliation
Rights Statement



This work has no parents.

Last modified

Downloadable Content

Download PDF