Plasma Imaging as a Diagnostic Tool for Laser-induced Breakdown Spectroscopy
Open Access
Author:
Mcnutt, Jessica Paige
Graduate Program:
Nuclear Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
None
Committee Members:
Igor Jovanovic, Thesis Advisor/Co-Advisor Kenan Unlu, Thesis Advisor/Co-Advisor Arthur Thompson Motta, Thesis Advisor/Co-Advisor
Keywords:
LIBS plasma laser
Abstract:
Laser-induced breakdown spectroscopy (LIBS) has been identi ed as a promising technique for the detection and characterization of nuclear materials and other materials relevant for nuclear forensics and international safeguards applications. LIBS is a material characterization method whereby a short-pulse, high-intensity laser is focused on the surface of a target to generate a plasma for spectral analysis to determine the elemental and potentially isotopic composition of the target. Shadowgraphic and fast-frame photographic imaging are two established techniques used to study the time-evolution and the rate of expansion of laser-produced plasmas over hundreds of nanoseconds. The modi cation of a LIBS experimental setup to include the capability to take photographic images and high-temporal resolution shadowgraphic images is presented. Analysis of uranium samples was performed in air and vacuum conditions. Shadowgraphic imaging was used to analyze laser produced plasma evolution in the rst 8 ns following laser-energy deposition on the surface. Algorithms were developed to measure the plasma radius as a function of time and the results of that analysis were compared to the Sedov-Taylor model.
