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Thermodynamic Metrology Group

Welcome
Temperature and humidity thumbnailThe Thermodynamic Metrology Group realizes, maintains, and disseminates the national measurement standards for temperature and humidity. The Group advances temperature and humidity measurements and applications; calibrates sensors and disseminates practical standards; participates in international comparisons to validate national standards; develops measurement methods, devices, and reference materials and data; assists users in the assessment of measurement uncertainty; prepares and promulgates evaluations and descriptions of temperature and humidity measurement processes; coordinates national and international temperature and humidity measurement standards and methods; and determines the uncertainty of the national standards of temperature and humidity with respect to fundamental thermodynamic definitions.
Programs/Projects

Humidity—The NIST Thermodynamic Metrology Group maintains and develops national standards of humidity (in the range 1 nmol/mol to 0.6 mol/mol of water concentration), and supports calibration of all types …

Thermometry—The NIST Thermodynamic Metrology Group maintains and develops national standards of temperature (in the range 0.65 K to 1235 K), and supports calibration of all types of contact thermometers up to …

Spectroradiometry of sources—Calibration standards for spectral radiance and spectral irradiance are disseminated in the form of transfer lamps and integrating sphere sources. These disseminated standards are made traceable to …

Accurate Flow Meter and Viscometer for Gases—Integrated circuits are made in reaction chambers, or process "tools", each of which receives gases from several mass flow controllers at rates which can be as small as 1 cubic centimeter per …

A Gas Pressure Scale Based on Primary Standard Piston Gauges—Accurate determinations of pressure are required for diverse applications such as the altitude of aircraft, barometric pressure for weather prediction, and process control in manufacturing.  The …

Physical Properties of Liquid Precursors— In striving to adhere to Moore's Law, the semiconductor industry is designing and using new metal-organic compounds. Precursor compounds deliver a metal atom to the surface of a hot silicon wafer …

High-Stability Transfer Standard for the Barometric Pressure Range of 100 Pa to 130 kPa—NIST has developed a new pressure transfer standard capable of absolute-mode and differential-mode operation in the range of 100 Pa to 130 kPa. This important pressure range spans the barometric …