Improved photometric standards and calibration procedures at NIST
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Improved Photometric Standards and Calibration Procedures at NIST
NIST has recently established a detector-based luminous intensity unit (candela, cd), which is derived from the NIST absolute cryogenic radiometer. Subsequently, the luminous flux unit (lumen, lm) and the luminance unit (cd/m2) have been established based on the detector-based candela, and now all the NIST photometric units are tied to the cryogenic radiometer. The illuminance unit is realized ...
متن کاملThe Detector-Based Candela Scale and Related Photometric Calibration Procedures at NIST
The candela, one of the SI base units, has been realized by using absolutely calibrated detectors rather than sources. A group of eight photometers was constructed using silicon photodiodes, precision apertures, and glass filters for V (λ) match. Their absolute spectral responsivities were calibrated against the NIST absolute spectral responsivity scale. The measurement chain has been significa...
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This document describes the procedures used at NIST to calibrate dc voltage standards in terms of the NIST volt. Three calibration services are offered by the Electricity Division: Regular Calibration Service (RCS) of client standard cells at NIST; the Volt Transfer Program (VTP) a process to determine the difference between the NIST volt and the volt as maintained by a group of standard cells ...
متن کاملImprovements in the Nist Calibration Service for Thermal Transfer Standards
We report on multiple improvements made in the calibration services offered for thermal converters and thermal transfer standards in the ac-dc Difference Standards and Measurement Techniques Project at NIST during the past year. The major improvement in this calibration is the increased efficiency made possible by the consolidation of three disparate calibration services – low voltage thermal t...
متن کاملA Technique for Force Calibration MEMS Traceable to NIST Standards
Characterizing the mechanical properties of materials and biological systems at the nanoscale requires accurate measurement of forces on the order of 10’s of μN and less. Many times custom fabricated MEMS actuators and load cells are employed to apply these forces. Force response of these devices may be very different from their anticipated response due to fabrication induced effects. This make...
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ژورنال
عنوان ژورنال: Journal of Research of the National Institute of Standards and Technology
سال: 1997
ISSN: 1044-677X
DOI: 10.6028/jres.102.022