Thermodynamic Metrology Group

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:

Do a Cooperative Research Project with us
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Be a post-doc
Join us as a high school student

Work with us as a college student
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Or contact a project PI directly to learn how to get involved.

Research Projects and Programs

Cold Core Technology Platform

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

Fixed Point Development : Non-Metals

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

Interferometry: INFER - Neutron Interferometric Microscopy of Small Forces and Hierarchical Structures

INFER is an NIST Innovations in Measurement Science (IMS) project that seeks to develop far field neutron interferometers to create multi-scale images (three

Photonic Dosimetry

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

Photonic Thermometry

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

Platform for Realizing Integrated Molecule Experiments (PRIME)

PRIME (Platform for Realizing Integrated Molecule Experiments) aims to establish primary, quantum-based realizations for both the radiometric watt and kelvin

Quantum Pascal: Fixed Length Optical Cavity (FLOC) Pressure Standards

This project is fundamentally changing the method for realizing and disseminating the SI unit of pressure, the pascale (Pa). The underlying principal behind

Reliable Vaccine Storage

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

Illustration of Thermal MagIC assembly with coils

Thermal MagIC: An SI-Traceable Method for 3D Thermal Magnetic Imaging and Control

We are developing a method to measure and regulate temperature throughout a three dimensional volume with Systeme International (SI)-traceable Thermal Magnetic

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Measurement Services Projects and Programs

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)

Pressure

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

Thermometry

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 Thermometry

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

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

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News and Updates

New Standard for Vaccine Fridges Unveiled

June 17, 2021

You know that part of your fridge that always freezes your lettuce? Or the section in your freezer door that leaves your popsicles a little mushy? Different

The Case of the Cloudy Filters: Solving the Mystery of the Degrading Sunlight Detectors

March 25, 2021

More than 150 years ago, the Sun blasted Earth with a massive cloud of hot charged particles. This plasma blob generated a magnetic storm on Earth that caused

In Search for Dark Matter, New Fountain Design Could Become Wellspring of Answers

November 27, 2020

You can’t see it. You can’t feel it. But the substance scientists refer to as dark matter could account for five times as much “stuff” in the universe as the

Thermal MagIC: New NIST Project to Build Nano-Thermometers Could Revolutionize Temperature Imaging

October 9, 2020

Cheaper refrigerators? Stronger hip implants? A better understanding of human disease? All of these could be possible and more, someday, thanks to an ambitious

Publications

Calibration of Hygrometers with the Hybrid Humidity Generator

September 23, 2021

Author(s)

Christopher W. Meyer, Tobias Herman, W. Wyatt Miller

We describe here the calibration of customer hygrometers using the NIST Hybrid Humidity Generator (HHG). This generator produces humidified air with water

NIST on a Chip: Photonic and Quantum-Based Sensors for Measurements of Pressure, Vacuum, Temperature and Beyond!

April 29, 2021

Author(s)

Jay H. Hendricks, Zeeshan Ahmed, Daniel Barker, Stephen Eckel, James A. Fedchak, Nikolai Klimov, Julia Scherschligt

At the core of the NIST on a Chip (NoAC) program is the idea that measurement technology can be developed to enable metrology to be done "outside the National

Outgassing rate comparison of seven geometrically similar vacuum chambers of different materials and heat treatments

April 23, 2021

Author(s)

James A. Fedchak, Julia Scherschligt, Sefer Avdiaj, Daniel Barker, Stephen Eckel, Ben Bowers, Scott O'Connell, Perry Henderson

We have measured the water and hydrogen outgassing rates of seven vacuum chambers of identical geometry but constructed of different materials and heat

Automated Piston Gauge Calibration System.

April 22, 2021

Author(s)

Julia Scherschligt, Yuanchao Yang, Katie M. Schlatter, Robert G. Driver, Christina D. Cross, John S. Quintavalle

Piston gauges or pressure balances are important primary standards for the realization of the SI unit of pressure, the Pascal. The National Institute of

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

Dynamic Humidity Measurements with the Hybrid Humidity Generator

The NIST Hybrid Humidity Generator (HHG) is NIST’s primary standard humidity generator and is used for calibration of all hygrometers sent to NIST. The HHG and

Dew-point measurements for water in compressed gases

This project has been completed. The paper reporting the results is provided here. The NIST Thermodynamic Metrology Group (TMG) used its standard gravimetric

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

Thermodynamic Metrology Group

Collaboration Opportunities

Research Projects and Programs

Measurement Services Projects and Programs

Archive Projects and Programs

News and Updates

Publications

Patents (pending and active, not including provisional)

Tools and Instruments

Awards

Highlights

Related Links

Contacts

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