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ACR II: improved absolute cryogenic radiometer for low background infrared calibrations
Adriaan C Carter1, Steven R Lorentz, Timothy M Jung
1Optical Technology Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA. adriaan.carter@nist.gov
Applied Optics
|March 9, 2005
Summary
A new absolute cryogenic radiometer (ACR II) enhances infrared detector calibration. This advanced instrument offers superior low-power performance and sensitivity for precise spectral calibrations and blackbody source measurements.
Area of Science:
- Metrology
- Optical Engineering
- Infrared Technology
Background:
- Sensitive infrared detectors require precise spectral calibration.
- Existing calibration standards limited the characterization of low-power infrared sources.
- Advancements in cryogenic radiometry are crucial for high-sensitivity measurements.
Purpose of the Study:
- To develop and characterize a second-generation absolute cryogenic radiometer (ACR II).
- To enable spectral calibrations of highly sensitive infrared detectors.
- To establish a primary standard for calibrating cryogenic blackbody sources.
Main Methods:
- Development of the absolute cryogenic radiometer II (ACR II).
- Utilized a cryogenic infrared monochromator for spectral analysis.
- Compared the performance of ACR II with the original absolute cryogenic radiometer (ACR).
Main Results:
- ACR II demonstrates significantly improved low-power performance compared to ACR.
- The new radiometer achieves a responsivity of 210 K/mW with a standard uncertainty of 7 pW for low-power measurements (<10 nW).
- ACR II serves as a primary standard for calibrating low-power infrared sources.
Conclusions:
- The ACR II represents a significant advancement in cryogenic radiometry.
- It enables more accurate spectral calibrations for sensitive infrared detectors.
- ACR II is essential for the precise characterization of cryogenic blackbody sources.