1. Optical Properties of Thin- film Uranium Oxide in the XUV Shannon Lunt, David D. Allred, R. Steven Turley, Elke Jackson, Kristi Adamson, Richard Sandberg Department of Physics and Astronomy, Brigham Young University

2. Mirrors in the EUV EUV: 50-1500nm (rough estimate) EUV: 50-1500nm (rough estimate) Difficulties: Difficulties: Absorption of MaterialsAbsorption of Materials Need multilayersNeed multilayers High VacuumHigh Vacuum Applications: Applications: XUV LithographyXUV Lithography Soft x-ray MicroscopySoft x-ray Microscopy AstronomyAstronomy Index of Refraction: ñ=n+ik

3. Why Study Uranium Oxide? IMAGE project showed benefits of UO 2 : IMAGE project showed benefits of UO 2 : High reflectivity.High reflectivity. Stability.Stability. Oxidation rate of Uranium: rate=12.52*ln(t)-31 Å/sec Oxidation rate of Uranium: rate=12.52*ln(t)-31 Å/sec or about 40 Å in 5 minutes. 1 Data on optical constants sparse. Data on optical constants sparse. Different sources disagree. Different sources disagree. 1 Oliphant, David T. Characterization of Uranium, Uranium Oxide and Silicon Multilayer Thin Films, Masters Thesis, Brigham Young University, 2000.

5. Making thin-film Uranium Oxide

6. Diagram of Films and Characterization Roughness - AFM. Roughness - AFM. Thickness of Uranium Oxide layer - XRD and ellipsometry. Thickness of Uranium Oxide layer - XRD and ellipsometry. Thickness of SiO 2 - ellipsometry before sputtering. Thickness of SiO 2 - ellipsometry before sputtering. Composition – XPS. Composition – XPS. Roughness UO x SiO 2 Si

7. Reflectivity Measurements McPherson, Model 225, 1-meter scanning monochromator McPherson, Model 225, 1-meter scanning monochromator 1200 lines/mm grating for 250Å to 1200Å1200 lines/mm grating for 250Å to 1200Å 600 lines/mm grating for 450Å to 1600Å.600 lines/mm grating for 450Å to 1600Å. Fit using IMD to calculate optical constants. Fit using IMD to calculate optical constants. Diagram of Monochromator

8. UOs1 reflectivity at 1216 Å

9. UOs3 reflectivity at 1216 Å

10. Future Work Alignment and Focusing of the 1200 lines/mm grating. Alignment and Focusing of the 1200 lines/mm grating. Improve the reflectivity measurement system. Improve the reflectivity measurement system. Measure the reflectivities of samples at wavelengths of interest. Measure the reflectivities of samples at wavelengths of interest. Calculate optical constants. Calculate optical constants.