Abstract: The focus of this thesis work is the use of 50 to 10 nanometer wavelength extreme ultraviolet (EUV) laser light as a next generation probe for mass spectrometry analyses at the micro (>100 nanometers) and nano (≤100 nanometer) spatial scales. While the unique properties of EUV light have revolutionized the semiconductor industry through nanoscale lithography fabrication, the use of EUV lasers with analytical instruments, like mass spectrometers, for high spatial resolution chemical analyses is a relatively untapped area. This unexplored territory is owed partly to only recently bringing EUV lasers to an accessible “bench-top” scale. Herein, I show how EUV laser ionization can be used with different types of mass spectrometers, i.e., devices that count ions, as a new route for interrogating solid materials with micro and nano scale lateral spatial resolution. I will focus on the application of a compact capillary discharge EUV laser operating at a wavelength of 46.9 nanometers connected to a time-of-flight (TOF) mass spectrometer, called the EUV TOF, for the analysis of nuclear and geologic materials at high spatial scales. I also show for the first time how the 46.9 nm EUV laser ionization source can be connected to a commercial magnetic sector mass spectrometer, called the EUV magnetic sector, with the aim of providing more precise and sensitive mass measurements than the EUV TOF. Overall, fields ranging from nuclear forensics, geology, the semiconductor industry, chemistry, biology, and any number of fields that require chemical information to be probed with high spatial resolution could benefit from the continued advancement of EUV laser ionization as a next generation probe for mass spectrometry.

Adviser: Carmen Menoni
Co-Adviser: Andrew Duffin
Non-ECE Member: Delphine Farmer
Member 3: Mario Marconi
Addional Members: Jorge Rocca

Publications:
Peer Reviewed Journal Publications
1. Rush, L.A.; Duffin, A.M.; Menoni, C.M. “Measuring Pb, Th, and U Inter-Element Ratios in Geological Materials Using Extreme Ultraviolet Laser Ablation and Ionization Mass Spectrometry,” Journal of Analytical Atomic Spectrometry, 2022, 37, 1902-1914.
2. Rush, L.A.; Cliff, J.B.; Reilly, D.D.; Duffin, A.M.; Menoni, C.S. “Isotopic Heterogeneity Imaged in a Uranium Fuel Pellet with Extreme Ultraviolet Laser Ablation and Ionization Time-of-Flight Mass Spectrometry,” Analytical Chemistry, 2021, 93, 1016-1024.

Peer Reviewed Conference Proceedings
1. Rush, L.A.; Cliff, J.B.; Reilly, D.D.; Duffin, A.M.; Menoni, C.S. “Imaging Isotopic Content at the Nanoscale Using Extreme Ultraviolet Laser Ablation and Ionization Mass Spectrometry,” Proceedings of SPIE 11886, International Conference on X-Ray Lasers, 2021, 118860Z, 1-8.
2. Solis Meza, E.; Rush, L.A.; Menoni, C.S.; Rocca, J.J.; Tallents G.; Wagenaars, E. “Time-of-Flight Mass Spectrometry to Determine Plasma Temperatures from Ablated Target Surfaces,” Proceedings of SPIE 11886, International Conference on X-Ray Lasers, 2021, 1188610, 1-8.
3. Bleiner, D.; Rush, L.A.; Rocca, J.J.; Menoni, C.S. “Rapid Quasi Non-Destructive 3D Chemical Visualization with Tabletop X-Ray Laser Mass Spectrometry,” Proceedings of SPIE 11111, X-Ray Lasers and Coherent X-Ray Sources: Development and Applications XIII, 2019, 111107, 1-10.

Program of Study:
ECE441: Optical Electronics
ECE507: Plasma Physics
ECE574: Optical Properties in Solids
ECE673: Thin Film Growth
CHEM532: Advanced Chemical Analysis
CHEM530 A,B,E: Special Topics in Analytical Chemistry
MSE504: Thermodynamics of Materials
MSE502 A,D: Special Topics in Materials Analysis