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Precise quantum measurement of vacuum with cold atoms
Daniel S Barker1, Bishnu P Acharya1, James A Fedchak1
1Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
The Review of Scientific Instruments
|December 31, 2022
Summary
National Institute of Standards and Technology (NIST) is developing cold-atom vacuum standards (CAVS) for ultra-high vacuum measurements. These primary pressure standards offer traceability to fundamental units, potentially replacing traditional gauges.
Area of Science:
- Metrology
- Atomic Physics
- Vacuum Science
Background:
- Traditional vacuum gauges like the Bayard-Alpert ionization gauge have limitations in accuracy and traceability.
- Ultra-high and extreme-high vacuum regimes require precise pressure measurements for scientific and industrial applications.
Purpose of the Study:
- To describe the development and principles of cold-atom vacuum standards (CAVS) at NIST.
- To establish a primary pressure standard traceable to fundamental physical constants.
- To develop a portable CAVS as a potential successor to conventional vacuum gauges.
Main Methods:
- Utilizing sub-millikelvin sensor atoms in a magnetic trap to measure pressure.
- Employing ab initio quantum scattering calculations to determine gas density from atom loss rates.
- Developing both laboratory-scale and portable CAVS instruments.
Main Results:
- CAVS provides pressure measurements traceable to the second and kelvin, realizing the pascal.
- Two CAVS versions developed: a laboratory standard for low uncertainty and a portable gauge.
- CAVS systems are integrated with advanced vacuum metrology equipment for calibration.
Conclusions:
- Cold-atom vacuum standards represent a significant advancement in vacuum metrology.
- CAVS offers a path towards primary pressure realizations in extreme vacuum environments.
- The portable CAVS shows promise as a next-generation vacuum gauge with enhanced traceability.
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