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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


  • 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


solar flare images and spectra
Credit: NASA

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.

News and Updates

Spotlight: SURF and Solar Storms

When the surface of the Sun erupts, it emits dangerous particles that can knock out GPS and communication links on our planet, but the rain of particles from a

EUV Calibrations for Satellite Sensors

Thanks to precision calibration measurements recently performed at NIST, satellites may soon be looking at sunlight with new and improved vision. On July 22

Projects and Programs


Optics Contamination

Charles S. Tarrio, Shannon B. Hill, Robert F. Berg, Sasa Bajt

Tools and Instruments

Beamline 10: Electron beam imaging

Beamline 10 of the Synchrotron Ultraviolet Radiation Facility is a diagnostics end-station used to determine the transverse size of the stored electron beam. In

Synchrotron Ultraviolet Radiation Facility (SURF III)

Products and Services


Group Leader

Office Manager