U.S. flag
        An official website of the United States government
          Here’s how you know
        Here’s how you know**Official websites use .gov**
              
              A **.gov** website belongs to an official government organization in the United States.
        **Secure .gov websites use HTTPS**
              
              A **lock** (  A locked padlock
) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. https://www.nist.gov/laboratories/tools-instruments/ultraviolet-scale-realization-facility-uv-srf
  Search NIST
    Search
              Menu

      


Close
    Topics
        All Topics
                                                        Advanced communications
                                                        Artificial intelligence
                                                        Bioscience
                                                        Buildings and construction
                                                        Chemistry
                                                        Climate
                                                        Cybersecurity
                                                        Electronics
                                                        EnergyEnvironment
                                                        Fire
                                                        Forensic science
                                                        Health
                                                        Information technology
                                                        Infrastructure
                                                        Manufacturing
                                                        Materials
                                                        Mathematics and statisticsMetrology
                                                        Nanotechnology
                                                        Neutron research
                                                        Performance excellence
                                                        Physics
                                                        Public safety
                                                        Resilience
                                                        Standards
                                                        Transportation
            Publications
            Labs & Major Programs
        Laboratories
                                Communications Technology Laboratory
                                  Engineering Laboratory
                                  Information Technology Laboratory
                                  Material Measurement Laboratory
                                  Physical Measurement LaboratoryUser Facilities
                                NIST Center for Neutron Research
                                  CNST NanoFab
                                                        Research Test Beds
                                                        Research Projects
                                                        Tools & InstrumentsMajor Programs
                                Baldrige Performance Excellence Program
                                  CHIPS for America Initiative
                                  Manufacturing Extension Partnership (MEP)
                                  Office of Advanced Manufacturing
                                  Special Programs Office
                                  Technology Partnerships Office
            Services & Resources
        Standards and Measurements
                                Calibration Services
                                  Laboratory Accreditation (NVLAP)
                                  Quality System
                                  Standard Reference Materials (SRMs)
                                  Standards.gov
                                  Time Services
                                  Office of Weights and MeasuresSoftware
                                                        Data
                                Chemistry WebBook
                                  National Vulnerability Database
                                  Physical Reference Data
                                  Standard Reference Data (SRD)
                                                        Storefront
                                                        License & PatentsComputer Security Resource Center (CSRC)
                                                        NIST Research Library
            News & Events
        News
                                                        Events
                                                        Blogs
                                                        Feature Stories
                                                        AwardsVideo Gallery
                                                        Image Gallery
                                                        Media Contacts
            About NIST
        About Us
                                Leadership
                                  Organization Structure
                                  Budget & Planning
                                                        Contact Us
                                                        Visit
                                                        Careers
                                Student programsWork with NIST
                                                        History
                                NIST Digital Archives
                                  NIST Museum
                                  NIST and the Nobel
                                                        Educational Resources
 
 TOOLS & INSTRUMENTS

Ultraviolet Scale Realization Facility UV SRF
    
  NIST Ultraviolet Scale Realization Facility
The detection system in the Ultraviolet Scale Realization Facility.A new facility has been commissioned to the establish ultraviolet spectral power responsivity in the air-ultraviolet spectral range between 200 nm and 400 nm. We successfully realized the spectral power responsivity scale from 200 nm to 400 nm using a laser-driven plasma light source with a relative standard uncertainty below 0.5 % (k=1). This Ultraviolet Scale Realization Facility (UV SRF) is based on the same monochromator used in the Ultraviolet Spectral Comparator Facility (UV SCF) to shorten the calibration chain. Establishing the responsivity scale and performing calibrations in similar facilities should remove any uncertainty caused by differences in bandpass, out-off-band radiation, spectral purity, collimation, or data interpolation.

The UV SRF is based on an ultraviolet-rich laser-driven light source, which is imaged onto the monochromator entrance aperture using two off-axis parabolic mirrors. The monochromator is a Czerny-Turner mount double grating instrument that has been modified with an absolute angular encoder on the first grating mount to establish the wavelength scale. The light leaving the monochromator is imaged into the measurement system with a magnification of 4 to reduce the angular divergence. The optical power is measured with absolute-cryogenic electrical substitution radiometer with updated electronics. The working standard detectors being calibrated were silicon photodiodes, which had been tested for uniformity, noise characteristics, and ultraviolet resistance.

Several modifications were necessary before a successful scale realization was possible:

 
      A pair of off-axis parabolic mirrors mounted together onto a single mount with mechanical pre-alignment.
A pair of off-axis parabolic mirrors mounted together onto a single mount with mechanical pre-alignment.An absolute angular encoder was installed on the first grating mount in the monochromator. Together with an absorption target of an aqueous solution 4 % holmium oxide in 10 % perchloric acid and the encoder it was used to establish the wavelength scale.
	The entrance apertures in the absolute-cryogenic radiometer (ACR) were realigned and a new mount designed to allow for reproducible assembly.
	The electronics package of the ACR was replaced with a newer version, which resulted in a slightly lower noise floor and more reliable operations.
	Compared to the Ultraviolet Spectral Comparator Facility we switched to a higher power laser-driven light source.
	The photodiodes being calibrated were mounted in lens tubes with apertures that mimic the layout of the ACR to ensure both detection systems are collecting the same light field. Also a new photodiode holder was used that helped securely hold them into place.
	The two off-axis parabolic mirrors that magnify the exit slit of the monochromator were mounted together onto a single mount with mechanical pre-alignment. This allowed much faster alignment of the optical system.In the end we calibrated three silicon photodiodes between 200 nm and 400 nm in 5 nm-steps. At each wavelength we performed several measurements at each wavelength to establish measurement statistics and reduce the overall statistical uncertainties. The total combined relative uncertainties of the spectral power responsivities for the three detectors were below 0.5 % (k=1) for the whole spectral region from 200 nm to 400 nm.
                  Optical / photometry / laser metrology and Optical physics and communications
  
            Organizations
      
      NIST HeadquartersLaboratory ProgramsPhysical Measurement LaboratorySensor Science DivisionOptical Radiation Group
              Details
          Campus
                    Gaithersburg
              Contact
      
        

Uwe Arp
    
      
  uwe.arp@nist.gov
  (301) 975-3233

  Edward Hagley
    
      
  edward.hagley@nist.gov
  (301) 975-6381

  Robert E Vest
    
      
  robert.vest@nist.gov
  (301) 975-3992
                      Related Tools & Instruments
      
                  Beamline 3: Extended Range Monochromator for Ultraviolet and Extreme-Ultraviolet Optical Properties and Calibrations
                                        Beamline 4: Ultraviolet Optical Properties and Calibrations
                                        Spectral comparator facilities
  Related Projects
      
                  Argon mini-arc meets its match: Use of a laser-driven plasma source in ultraviolet-detector calibrations
                                        Extreme Ultraviolet Detector Calibration Service
                                        Bilateral Comparison of Spectral Responsivity in the Vacuum-Ultraviolet
  Related Publications
      
                  Eliminating the Middleman: Ultraviolet Scale Realization using a Laser-Driven Plasma Light Source
                                        Argon mini-arc meets its match: use of a laser-driven plasma source in ultraviolet-detector calibrations
                                        UV radiometry using synchrotron radiation and absolute cryogenic radiometry
                                        The New Ultraviolet Spectral Responsivity Scale Based on Cryogenic Radiometry at Synchrotron Ultraviolet Radiation Facility III
                                        New Ultraviolet Radiometry Beamline at the Synchrotron Ultraviolet Radiation Facility at NIST

    
    Created August 24, 2015, Updated April 5, 2021
 HEADQUARTERS
            100 Bureau Drive
              Gaithersburg, MD 20899301-975-2000
            Webmaster | Contact Us | Our Other Offices
        Twitter
            
Facebook
            
LinkedIn
            
Instagram
            
YouTube
            
Giphy
            
RSS Feed
            
Mailing List
                              How are we doing? Feedback

  
  Site Privacy
                      Accessibility
                      Privacy Program
                      Copyrights
                      Vulnerability Disclosure
                      No Fear Act Policy
                      FOIA
                      Environmental Policy
                      Scientific Integrity
                      Information Quality Standards
                      Commerce.gov
                      Science.gov
                      USA.gov
                      Vote.gov