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Physical Measurement Laboratory /Sensor Science Division

Fundamental Thermodynamics Group

The Fundamental Thermodynamics Group realizes, maintains, and disseminates the national measurement standards for pressure, vacuum, and leaks. Additionally, the group provides vital research towards improving measurement methods and standards for temperature and pressure along with other related measurement quantities.

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 including dissemination of the national measurement standards for pressure, vacuum, and leaks. 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
Cold atoms can be useful sensors for a host of different phenomena including inertial forces like acceleration and rotation, gravity, magnetic fields, vacuum and time. However, most of these applications are still confined to the laboratory. Building robust, field-deployable quantum sensors made
photonic calorimeter/dosimeter

Photonic Dosimetry

Ongoing
With this effort, NIST is responding to industry needs for traceable, measurement solutions that can resolve spatial variations of absorbed dose at the level of individual components on a silicon wafer or bacteria on surgical instruments. Presently, there is only limited traceability to national
SPoT chip

Photonic Thermometry

Ongoing
Why do we need reliable temperature metrology? Temperature, the second most measured physical property after time and frequency, is indispensable to innumerable industries, military services, medicine, climate, and weather forecasts – precise, accurate, and rapid temperature metrology enables much
Platform for Realizing Integrated Molecule Experiments

Platform for Realizing Integrated Molecule Experiments (PRIME)

Ongoing
Blackbodies realize a clear relationship between radiated power and temperature through Planck’s law. While a reliable instrument for temperature and power calibrations, blackbodies are afflicted with a plethora of systematics (e.g., non-ideal emissivity, propagation loss, temperature gradients
FLOC

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

Ongoing
This project enables a quantum-based, SI-traceable method for realizing the pascal (Pa) while improving accuracy and allowing the replacement of existing mercury manometer pressure standards. The Fixed Length Optical Cavity (FLOC) pressure standard is a laser-based, SI-traceable primary pressure
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Measurement Services Projects and Programs

pressure measurement items

Pressure/Vacuum Calibrations

Ongoing
Piston Gauge (29010C - 29040S) This service provides calibrated secondary standard piston gauges, calibrated electronic pressure instruments, and special tests of customer supplied piston gauges. Measurements of pressure are available for submitted calibration items for the range from 10 kPa to 280
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Archive Projects and Programs

Acoustic Thermometer

Acoustic Thermometry

Completed
Data from the NIST acoustic thermometer will form an improved basis for the equations used with platinum resistance thermometry, which is the primary mechanism to disseminate accurate temperature standards. Objective: To obtain measurements of thermodynamic temperature in the range between 273 K and
photo of membrane in shock tube

Dynamic Pressure

Ongoing
Measurement Platform: We are developing a photonics based dynamic pressure measurement platform that will enable traceable, accurate measurement of dynamic pressure. To this end we are developing fast scanning laser absorption spectroscopy techniques that enable rapid measurement of pressure
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News and Updates

Publications

Effect of ''glancing'' collisions in the cold atom vacuum standard

Author(s)
Stephen Eckel, Daniel Barker, James A. Fedchak, Jacek Klos, Julia Scherschligt, Eite Tiesinga
We theoretically investigate the effect of "glancing" collisions on the ultra-high-vacuum pressure readings of the cold-atom vacuum standard (CAVS), based on

Spectroscopy of laser cooling transitions in MgF

Author(s)
Nickolas Pilgram, Benjamin Baldwin, David La Mantia, Stephen Eckel, Eric Norrgard
We measure the complete set of transition frequencies necessary to laser cool and trap MgF molecules. Specifically, we report the frequency of multiple low $J$

Collision-resolved pressure sensing

Author(s)
Daniel Carney, Daniel Barker, Thomas W. LeBrun, David Moore, Jacob Taylor
Heat and pressure are ultimately transmitted via quantized degrees of freedom, like gas particles and phonons. While a continuous Brownian description of these

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. cm 3/s at 0 °C). The calibration can be performed directly

Vacuum Gauges

Most calibrations of vacuum gauges are based on a known gas flow rate that is generated by one of two flow meters that operate at constant pressure. The "piston
3m UIM w/ Jay Hedricks

Low Pressure Gauges

NIST has developed best-in-the-world primary standard pressure measurement capabilities for pressures spanning the range of 0.01 Pa to 360 kPa through the
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

Stephen Eckel

2024 PECASE - Stephen Eckel

Stephen Eckel is recognized for his pioneering work in applying cold-atom physics to solve real-world measurement problems, investigating
Nikolai Klimov

2024 PECASE - Nikolai Klimov

Nikolai Klimov is recognized for transformational research in photonic sensors for thermometry, dosimetry, humidity, and vacuum and for

Press Coverage

Highlights

Related Links

Contacts

Group Leader (Acting)

Office Manager