Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Thermodynamic Metrology Group

The Thermodynamic Metrology Group realizes, maintains, and disseminates the national measurement standards for temperature, humidity, pressure, vacuum, and leaks.

The group mission is to advance the state of the art in measurement of thermodynamic quantities. We have active efforts in optics, nano-photonics, and quantum-based metrology along with traditional precision measurements to advance U.S. industry. We collaborate nationally and internationally, and engage in metrology education and outreach.

News and Updates

Projects and Programs

Dynamic Pressure

Manufacturing processes by their very nature require a judicious, time-dependent use of pressure and temperature to transform a base material into a valuable

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)

Hybrid Humidity Generator

NIST's new primary standard humidity generator, the Hybrid Humidity Generator (HHG), replaces the NIST 2-Pressure Humidity Generator, Mark 2 (2-P). The HHG

Publications

A photonic pH sensor based on photothermal spectroscopy

Author(s)
Zeeshan Ahmed, Nathan J. Castro, Matthew R. Hartings
Although the determination of pH is a standard laboratory measurement, new techniques capable of measuring pH are being developed to facilitate modern

Johnson Noise Thermometry

Author(s)
Weston L. Tew, Jifeng Qu, K L. Zhou, Samuel P. Benz, Horst Rogalla, David R. White
Johnson noise thermometers infer thermodynamic temperature from measurements of the thermally-induced current fluctuations that occur in all electrical

Chemistry from 3D-printed objects

Author(s)
Matthew R. Hartings, Zeeshan Ahmed
3D printing technology has started to take hold as an enabling tool for scientific advancement. Born from the marriage of computer-aided design and additive

Tools and Instruments

Awards

Contacts

Group Leader

Office Manager