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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 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
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
prototype system

Fixed Point Development : Non-Metals

Ongoing
A fixed point is a reproducible reference temperature, usually either melting of freezing of a pure substance, that allows a standardized interpolation scheme for the purposes of temperature scale dissemination. Most SPRTs are long-stem designs that require immersion-type fixed points incorporating
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

Photonic Thermometry

Ongoing
NEED Temperature measurement is critical to innumerable industries – precise, accurate, and rapid temperature sensing enables much of the modern technology on which we depend. Most of these temperature sensors are based on a temperature-dependent resistance measurement of a strain-free metal wire or
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
Alex Rodriguez with data logger

Reliable Vaccine Storage

Completed
Our group examines best practices for the storage and monitoring of vaccines in partnership with the Centers for Disease Control and Prevention’s (CDC) Vaccine Supply and Assurance Branch. Vaccines are highly temperature sensitive, and inappropriate storage conditions can render them ineffective
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Measurement Services Projects and Programs

GH_gascollectionsys

Humidity

Ongoing
Our goals include: Providing SI traceability of humidity standards through use of standardized realization methods, and supporting humidity measurements in the U.S. and abroad through calibrations and proficiency testing Ensuring the equivalence of US humidity standards with those of other countries
pressure measurement items

Pressure

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
triple point cell

Thermometry

Ongoing
The NIST Thermodynamic Metrology Group supports industry and advances measurement science through an extensive suite of thermometry calibration services as well as research projects aimed at improving the utility for the International Temperature Scale. We also develop guidelines, and contribute to
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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

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

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

Press Coverage

Highlights

Related Links

Contacts

Group Leader

Office Manager