Abstract: Probing chemical information at the nanoscale (≤100 nm) is important to understand the composition, origin, or quality of materials in fields like the semiconductor industry, biology, geology, or nuclear forensics. Lasers combined with mass spectrometers offer a powerful and versatile tool towards the goal of high spatial resolution materials analysis. However, current laser-based mass spectrometry methods have a spatial resolution that is limited to the microscale because of the optical wavelength lasers (i.e., IR to UV) that are typically employed in these set-ups. To overcome the limited resolution of current techniques, our group has developed an extreme ultraviolet laser ablation and ionization mass spectrometer (EUV MS) that offers <100 nm lateral and depth resolution in organic and inorganic materials. The EUV laser, operating at a wavelength of 46.9 nm (26.4 eV photon energy), is unique because it is highly absorbed by materials within depths of tens of nanometers and can efficiently ionize atoms and molecules with a single photon. The EUV laser can therefore be focused down to nanoscale sized spots for efficient material removal and ionization that is not possible with longer wavelength lasers. The analysis of nuclear and geological materials with the EUV MS system will be presented. Additionally, progress on a new generation EUV MS system that will offer increased accuracy and precision will be discussed.

Adviser: Carmen S. Menoni
Co-Adviser: Andrew M. Duffin
Non-ECE Member: Delphine K. Farmer, Chemistry
Member 3: Mario C. Marconi, ECE
Addional Members: Jorge J. Rocca, ECE

Publications:
1. 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.
2. 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.
3. 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.
4. 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.
5. Bleiner, D.; Trottmann, M.; Muller, R.; Rush, L.A.; Kuznetsov, I.; Cabas-Vidani, A.; Romanyuk, Y.; Tiwari, A.; Patzke, G.R.; Menoni, C.S.; Rocca, J.J. “3D Chemical Mapping of Thin Films by Means of X-Ray Laser Microanalysis”, In: Kozlova, M.; Nejdl, J. (eds) X-Ray Lasers 2018. ICXRL 2018. Springer Proceedings in Physics, 2018, 241, 3-10, Springer, Cham.

Publications in preparation
1. Rush, L.A.; Duffin, A.M.; Menoni, C.M. “Matrix Effects of Pb, Th, and U Inter-Element Ratios in Geological Materials Using Extreme Ultraviolet Laser Ablation and Ionization Mass Spectrometry”, manuscript in preparation for submission to the Journal of Analytical Atomic Spectrometry.
2. Wilson, S.A.; Rush, L.A.; Solis Meza, E.; Vysin, L.; Lolley, J.A.; Tallents, G.J.; Rocca, J.J.; Menoni, C.S. “Extreme Ultraviolet Laser Ablation and Time of Flight Mass Spectrometry of Gold, Aluminum and Copper Targets”, manuscript in preparation for submission to the IEEE Photonics Journal.

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
MSE504 (Thermodynamics of Materials)
MSE502 A,D