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Missile defense transfer radiometer (MDXR)

The Missile Defense transfer Radiometer (MDXR) is a cryogenic transfer radiometer for providing calibrations of collimated infrared beams in users' cryo-vacuum test facilities against the NIST primary optical power standards. The MDXR has both a filter radiometer and a cryogenic Fourier transform spectrometer (Cryo-FTS), both of which operate in vacuum at a temperature below 20 kelvin, and interfaces to customer chambers through an end flange. The Cryo-FTS provides continuous spectral coverage from 4 μm to 20 μm. An onboard absolute cryogenic radiometer (ACR) provides spectrally integrated power measurements down to a noise floor of approximately 3.5 pW. An onboard 7 cm collimator and cryogenic blackbody serve as a stability monitor and a spectral calibration source for the Cryo-FTS. The MDXR has been used multiple times at a variety of facilities since it was first operational in May 2010.


  • Measure absolute power with onboard ACR.
  • Monitor and calibrate its own spectral throughput with onboard blackbody calibration source and 7 cm collimator.
  • Fourier-transform spectrometer with spectral resolution of 0.85 cm-1 from 4 μm to 20 μm.
  • Measure collimated beam with spectral irradiance input levels between 10-15 W/cm2/μm and 10-9 W/cm2/μm.
  • Spectrally resolve beam over IR wavelengths from 2 µm to 30 µm with variable bandpass filters.
  • Evaluate linear polarization of collimated beams.
  • Easily transported with support equipment.
  • Self-contained vacuum and cryogenic systems for operation external to test chamber being evaluated.
Created January 20, 2010, Updated November 15, 2019