Keywords
soft x-ray, EUV, low-angle reflector, nickel, uranium oxide, uranium nitride, synchrotron, EUV/soft X-ray astronomy, optical constants
Abstract
Uranium oxide and uranium nitride thin films reflect significantly more than all previously known/standard reflectors (e.g., nickel, gold, and iridium) for most of the 4-10 nm range at low angles of incidence. This work includes measurements of the EUV/soft x-ray (2-20 nm) reflectance of uranium-based thin films (~20 nm thick) and extraction of their optical constants (d and ?). We report the reflectances at 5, 10, and 15 degrees grazing incidence of air-oxidized sputtered uranium, reactively sputtered (O2) uranium oxide, and reactively sputtered (N2) uranium nitride thin films measured at Beamline 6.3.2 at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBNL). Additionally, we report optical constants of reactively sputtered uranium oxide at nine wavelengths from 4.6 to 17.5 nm derived from ALS angle-scan reflectance measurements. We also report optical constants of uranium nitride at 13 and 14 nm. We compare the reflectance of these uranium-compound thin films to gold, nickel (and nickel oxide), and iridium thin films from 2.5 to 11.6 nm. These metal thin films were chosen for comparison due to their wide use in EUV/sift x-ray applications as low-angle, thin-film reflectors. The uranium compounds can exhibit some surface oxidation in ambient air. There are important discrepancies between UO2's and UN's actual thin-film reflectance with those predicted from tabulated optical constants of the elemental constituents of the compounds. These differences are also demonstrated in the optical constants we report. Uranium-based optics applications have important advantages for zone plates, thin-film reflectors and filters.
Original Publication Citation
Richard L. Sandberg, David D. Allred, Shannon Lunt, Marie K. Urry, R. Steven Turley, "Optical Properties and Application of Uranium-based Thin Films for the Extreme Ultraviolet and Soft X-ray Region," in Optical Constants of Materials for UV to X-Ray Wavelengths, edited by Regina Soufli, and John F. Seely, Proceedings of SPIE, Vol. 5538, (SPIE, Bellingham, WA, 24) 17-118. [http://spiedigitallibrary.org/proceedings/resource/2/psisdg/5538/1/17_1?isAuthorized=no][http://dx.doi.org/1.1117/12.56717].
BYU ScholarsArchive Citation
Sandberg, Richard L.; Allred, David D.; Lunt, Shannon; Urry, Marie K.; and Turley, R. Steven, "Optical Properties and Application of Uranium-based Thin Films for the Extreme Ultraviolet and Soft X-ray Region" (2004). Faculty Publications. 1041.
https://scholarsarchive.byu.edu/facpub/1041
Document Type
Peer-Reviewed Article
Publication Date
2004-10-14
Permanent URL
http://hdl.lib.byu.edu/1877/2917
Publisher
Society of Photo Optical Instrumentation Engineers (SPIE)
Language
English
College
Physical and Mathematical Sciences
Department
Physics and Astronomy
Copyright Status
© 2004 Society of Photo Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
Copyright Use Information
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