Ultraviolet Radiation Group
Provides our National standards for ultraviolet (UV) and extreme-ultraviolet (EUV) radiometry. We operate the SURF III, a 380 MeV electron storage ring, which provides a continuum source of synchrotron radiation from soft x-rays through the far infrared.
Synchrotron Ultraviolet Radiation Facility SURF III
- Provides our National standards for ultraviolet (UV) extreme-ultraviolet (EUV) radiometry
- Monitoring space weather and solar variability
- Advancing industrial uses – e.g. EUV microlithography, UV curing
- Provides continuum radiation from the soft x-ray to the infrared spectral regions, with ideal output profile for EUV studies related to solar physics and the development of EUV lithography
- Calculable irradiance traceable to the SI units to less than 1 % absolute uncertainty from 4 nm to 400 nm
- Beamlines equipped for detector, spectrometer, and lamp calibrations; reflectometry and transmission measurements; degradation and lifetime studies
- Carefully characterized and maintained source, operated in a clean hydrocarbon-free vacuum
Measurement services and other calibrations
- Photodiode calibrations from 5 nm to 400 nm and UV source lamp calibrations as through NIST Measurement Services
- Calibration of all NASA and NOAA solar observing satellite instruments
- Mirror reflectivity for solar telescopes and EUV lithographic tools
Research
- UV/EUV-induced optics contamination of optics in space and in EUV lithography tools
- Establish traceability to the SI units and reduce absolute uncertainties over the whole range 4 nm to 400 nm
- Optical properties of materials in the VUV and EUV
- Development and characterization of new detectors and imaging systems in the VUV and EUV
- Theoretical and experimental treatment of diffraction contributions in source-based radiometry
- Using improved understanding of synchrotron physics to reduce beam noise to improve suitability of source for infrared microscopy
Highlights
Images and Spectra of a solar flare taken from the Solar Dynamics Observatory (SDO) Mission launched in February 2010. Top three panels (l to r): Images showing magnetic loops of the solar flare taken at 9.4 nm, 33.5 nm, and 17.1 nm, respectively, taken by the Atmospheric Imaging Assembly (AIA) aboard the SDO; Fourth panel: graphic related to magnetic field strength at the flare taken by the Helioseismic and Magnetic Imager (HMI). Bottom: Time history of flare emission at 9.4 nm and 33.5 nm taken by the Extreme-Ultraviolet Variability Experiment (EVE) instrument. The initial calibration of EVE and the periodic recalibrations through a duplicate EVE on rocket underflights were done at SURF III. The AIA is periodically cross calibrated against EVE.
