Missile defense transfer radiometer (MDXR)

The Missile Defense transfer Radiometer (MDXR) is a new transfer radiometer for providing calibrations of collimated infrared beams in users’ cryo-vacuum test facilities against the NIST primary optical power standards at higher spectral resolution than the BMDO transfer radiometer (BXR). The MDXR can also evaluate non-Planckian sources that may fall in between the narrow filter bandpasses of the BXR. In addition to having filter radiometer capabilities equivalent to the BXR, the MDXR has a cryogenic Fourier transform spectrometer (Cryo-FTS) that provides continuous spectral coverage from 4 μm to 20 μm. An 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 system is fully assembled and currently undergoing testing and calibration in LBIR. The Cryo-FTS system has been demonstrated to function as designed at cryogenic vacuum conditions at a base temperature of 20 K, and initial results from the Cryo-FTS show radiometric stability with 1 % over a period of several weeks when viewing a blackbody source. The MDXR is expected to take over the calibration schedule of the BXR once testing is completed, offering additional modes of operation and capabilities to the user community. The first planned deployment of MDXR will be to the AEDC 7V chamber 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 irradiance input levels between 10^-15 W/cm² and 10^-9 W/cm².
• Spectrally resolve beams over IR wavelengths from 2 µm to 30 µm with variable bandpass filters.
• Evaluate linear polarization of collimated beam.
• Easily transported with support equipment.
• Self contained vacuum and cryogenic systems for operation external to test chamber being evaluated.