Thermometry Group Mission

To create, maintain, and disseminate best-in-the-world capabilities in the measurement of temperature and humidity, and to enable measurements by industry to be traceable to NIST standards at the highest levels of accuracy.

Our activities in support of this mission include:

The menu box at the top of the page gives links to pages on these topics.

Research, calibration services, and national standards in the field of radiation thermometry are the responsibility of a separate group at NIST: the Optical Thermometry and Spectral Methods Group of the Optical Technology Division

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Thermometry Group Program Overview

Process and quality control and equity in commerce ultimately depend on the accuracy of measurements. This generally requires calibration of instruments against, or use of procedures assuring traceability to, national standards. Therefore, measurement standards and calibration services are a very important part of our activities, with calibrations performed this year for a wide range of clients across the country. Our commitment to provision of these services involves many facets.

In the field of thermometry, our activities include:

• the realization, maintenance, and improvement of the International Temperature Scale of 1990 (ITS-90)
• measurements of thermodynamic temperatures with improved accuracy, by such techniques as Acoustic Thermometry,
• continuing comparisons of fixed-point cells of the defining fixed-point materials and of our realization of the ITS-90 with those of other nations, both globally and regionally,
• development of next-generation technologies in temperature measurement, such as Johnson Noise Thermometry, and

• development of suitable mechanisms that allow customers in the field and in secondary calibration laboratories to realize their required measurement accuracy.

In the field of humidity and related measurements, our activities include:

• the realization and maintenance of the US national standards in humidity,
• development of new humidity generators and a gravimetric hygrometer that extend the range and accuracy of our calibration services,
• continuing comparisons of hygrometers and humidity generators with those of US industry and of other nations, both globally and regionally,
• development of Cavity Ring-Down Spectroscopy as a primary method for the measurement of water vapor at extremely low concentrations in gases, and

• development of Evanescent Wave Cavity Ring-Down Spectroscopy as a method for sensitive detection of a variety of trace impurities in either gases or liquids, with potential applications in sensing of a variety of hazardous or detrimental contaminants in processing or natural environments.

While these Programs serve a wide range of customers, we also focus on specific strategic technologies, such as those relating to semiconductor device manufacturing. As part of NIST's National Semiconductor Metrology Program. We have major programs in

• the development of improved thermocouple thermometry for in situ calibration of rapid thermal processing (RTP) systems,

• the development and metrological characterization of humidity generators and hygrometers that operate at the extremely low water vapor concentrations of interest in semiconductor processing.

Within the context of these efforts, we interact with numerous industrial collaborators to coordinate our research with industrial need.

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Thermometry Staff

Precision Themometry Workshop:
Course Outline
Registration and Contacts
General Information

ITS 90 Fixed Point Cell Mini Workshop:
Course Outline
Registration and Contacts
General Information

Liquid In Glass Thermometer Mini Workshop:
Course Outline
Registration and Contacts
General Information

Calibration for RTP
T > 83.8 K
T < 84 K
Noise Thermometry
Sealed Cell Fixed Point Development
Thermocouple Research
Thermodynamic Temperature Measurements