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Physical Measurement Laboratory /Sensor Science Division

Thermodynamic Metrology Group

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

Photonic thermometer packages
Photonic Thermometry
three boxes
Realizing Pressure, Temperature, and Length using Optical Interferometry

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.

Collaboration Opportunities

We invite collaboration on joint research, technology, and standards development projects. Want to work with us? Here’s how:

Or contact a project PI directly to learn how to get involved.

Research Projects and Programs

background molecule

Cold Core Technology Platform

Ongoing
We are building a cold-atom based sensor program that represents a new approach to metrology—to establish a set of chip-scale tools that enable real-world use
prototype system

Fixed Point Development : Non-Metals

Ongoing
We are developing new fixed points and new maintenance systems for use with Standard Platinum Resistance Thermometers (SPRTs) below the triple point of water
photonic calorimeter/dosimeter

Photonic Dosimetry

Ongoing
As part of the NIST on a Chip program, the Photonic Dosimetry project is developing in-situ sub-micrometer ionizing-radiation dosimetry and calorimetry leading
SPoT

Photonic Thermometry

Ongoing
Photonic Thermometry is a cutting-edge research program at NIST that aims to break the fundamental limitations of electrical resistance-based thermometry and
Alex Rodriguez with data logger

Reliable Vaccine Storage

Ongoing
We study provider-level vaccine storage and temperature monitoring methods to develop best practice guidance for public health audiences.
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Measurement Services Projects and Programs

GH_gascollectionsys

Humidity

Ongoing
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)
pressure measurement items

Pressure

Ongoing
The NIST Thermodynamic Metrology Group (TMG) provides critical research into pressure measurement capabilities improving uncertainties in user facilities and
triple point cell

Thermometry

Ongoing
The NIST Thermodynamic Metrology Group maintains and develops national standards of temperature (in the range 0.65 K to 2011 K), and supports calibration of all
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Archive Projects and Programs

Acoustic Thermometer

Acoustic Thermometry

Completed
By measuring the speed of sound in argon gas, we have determined thermodynamic temperature with unprecedented accuracy in the range 0 °C to 552 °C. Our results
photo of membrane in shock tube

Dynamic Pressure

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

bragg grating

Hooked on Photonics? Math to the Rescue

Photonic thermometers – which measure temperature using light – have been around in optical fiber form for decades. These devices, called fiber Bragg gratings
Stephen Eckel

A Primary Standard for Measuring Vacuum

A novel, quantum-based vacuum gauge system invented by researchers at the National Institute of Standards and Technology (NIST) has passed its first test to be

Publications

2022 Update for the Differences Between Thermodynamic Temperature and ITS 90 Below 335 K

Author(s)
Christof Gaiser, Bernd Fellmuth, Roberto Maria Gavioso, Murat Kalemci, Vladimir Kytin, Tohru Nakano, Laurent Pitre, Anatoli Pokhodun, Patrick Rourke, Richard Rusby, Peter P.M. Steur, Weston L. Tew, Robin James Underwood, Rod White, Inseok Yang, Jintao Zhang
In 2011, a working group of the Consultative Committee for Thermometry published best estimates of the differences between thermodynamic temperature (T) and the

Precise Quantum Measurement of Vacuum with Cold Atoms

Author(s)
Daniel Barker, Bishnu Acharya, James A. Fedchak, Nikolai Klimov, Eric Norrgard, Julia Scherschligt, Eite Tiesinga, Stephen Eckel
We describe the cold-atom vacuum standards (CAVS) under development at the National Institute of Standards and Technology. The CAVS measures pressure in the

Patents (pending and active, not including provisional)

Triple Point Immersion Cell Article (pending), US20210072098A1. Tew & Nanninga. March 11, 2021

Deformometer for determining deformation of an optical cavity optic, US Patent 10,935,370. Ahmed, Douglass, Eckel, Egan, Hendricks, Stone. Mar 2, 2021

Deformometer for determining deformation of an optical cavity optic, US Patent 10,816,325. Ahmed, Douglass, Eckel, Hendricks, Stone. Oct 27, 2020

Photonic calorimeter and process for performing calorimetry, US Patent 10,782,421. Tosh, Ahmed, Fitzgerald, Klimov. Sep 22, 2020

Photonic dosimeter and process for performing dosimetry, US Patent 10,718,872. Tosh, Ahmed, Fitzgerald, Klimov. Jul 21, 2020

Uniaxial counter-propagating monolaser atom trap (pending), US20200120785A1. Eckel, Barker, Fedchak, Scherschligt, Norrgard, Klimov. Apr 16, 2020

High-resolution photonic thermometer article (pending), US20200103594A1. Klimov, Douglass, Ahmed. Apr 2, 2020

Photonic quantum dew point sensor (pending), US20200041431A1. Herman, Klimov, Purdy. Feb 10, 2020

Optofluidic Flow Meter, US Patent 10,151,681 B2. Ahmed & Cooksey. Dec 11, 2018

Optical temperature sensor and use of same, US Patent 9,726,553. Ahmed, Semanick, Taylor, Fan, Hafezi, Xu, Strouse. Aug 8, 2017

Tools and Instruments

Leak Artifacts

Leak artifacts are calibrated in the range 1 x 10-6 to 1 x 10-13 mol/s (2 x 10-2 to 2 x 10-9 std. cm3/s at 0 °C). The calibration can be performed directly
PG

Piston gauges and pressure transducers

Piston gauges are used to calibrate customer piston gauges and pressure sensing devices. Piston gauges are calibrated via a direct comparison to another piston

Awards

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Press Coverage

Highlights

Related Links

Contacts

Group Leader

Office Manager