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Transfer radiometers and reference detectors


We have developed several portable radiometers to transfer the primary detector-based scales for optical power, radiance, and irradiance in the infrared spectral region to user sites for calibration and validation of cryo-vacuum based radiometric facilities. Deployment of these radiometers to user sites helps provide end-to-end calibration of optical systems, and complements the blackbody broadband calibrations performed at NIST.


Use of these radiometers depends on a primary standard detector and a secondary transfer detector. We generally employ an absolute cryogenic radiometer (ACR) as the primary standard detector to calibrate the transfer detector, a Si:As blocked-impurity-band (BIB) detector. The transfer detector is then integrated into a transfer radiometer for calibration of optical systems at user sites. We are presently developing a pair of next-generation reference detectors: an ultra-sensitive ACR (Pico-Watt ACR) and a high quantum efficiency trap detector comprised of two BIB detectors (BIB-trap).


Missile defense transfer radiometer (MDXR) – Transfer radiometer with integrated cryogenic Fourier transform spectrometer for full spectral capability. Completed in 2009 and deployed to several customer chambers per year since 2010. Contains both a primary standard detector (ACR) and a calibrated secondary standard detector (BIB).


BDMO transfer radiometer (BXR) – Filter-based transfer radiometer with a multi-year legacy of stable calibrations at our facility and of optical systems at user sites. Contains a secondary standard detector (BIB) which has been calibrated against a primary standard at our facility.

Thermal infrared transfer radiometer (TXR) – Transfer radiometer for calibration of near-room-temperature extended-area blackbodies. Multi-year legacy of calibrations at NIST and of optical systems at user sites.

BIB-trap detector

BIB-trap detector – Reference detector under development for use as a secondary standard. Detector designed for high quantum efficiency and flat spectral response between 4 µm and 28 µm.

Pico-Watt ACR – Reference detector under development for use as a primary standard in low power calibrations. Detector designed to enable calibration of 1 pW with less than 1 % uncertainty.

Created January 29, 2010, Updated March 2, 2020