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    Redefining Vacuum Measurements: NIST’s Innovative Approach

    ByThemba Hadebe

    Nov 15, 2023
    Redefining Vacuum Measurements: NIST’s Innovative Approach

    Vacuum measurements play a critical role in various fields, from chip manufacturing to quantum computing. Precise measurements of ultra-low gas pressures are essential for ensuring the quality and functionality of technological advancements. Scientists at the National Institute of Standards and Technology (NIST) have unveiled a groundbreaking method called Cold Atom Vacuum Standard (CAVS) to accurately measure these extremely low gas pressures.

    What is CAVS?

    CAVS, developed by NIST researchers over the course of seven years, represents a significant advancement in vacuum pressure measurement techniques. Unlike conventional methods that rely on calibration to reference pressure readings, CAVS serves as a “primary standard.” This means that it independently provides highly accurate measurements without the need for calibration.

    Validating CAVS

    NIST researchers conducted extensive testing to validate the accuracy and reliability of CAVS. Their results, published in the journal AVS Quantum Science, demonstrate that CAVS measurements align with the traditional “gold standard” method for measuring low pressures. This breakthrough establishes CAVS as a reliable and accurate technique for measuring vacuum pressures.

    Applications of CAVS

    The applications of CAVS extend beyond semiconductor manufacturing. Its ability to measure lower vacuum pressures, reaching levels as low as a trillionth of Earth’s atmospheric pressure, opens doors for advancements in chip manufacturing and future scientific explorations. Furthermore, CAVS operates based on well-understood principles of quantum physics, allowing for accurate readings without the need for additional adjustments or calibration.

    How Does CAVS Work?

    CAVS leverages a cold gas consisting of lithium or rubidium atoms trapped in a magnetic field. When illuminated by a frequency-tuned laser, these atoms fluoresce, and the intensity of this glow is measured to determine the number of trapped atoms precisely. When connected to a vacuum chamber, the trapped atoms interact with the residual atoms or molecules in the chamber. Each collision reduces the number of atoms and the emitted light’s intensity, providing a sensitive measure of pressure. This relationship between intensity and the number of molecules is governed by quantum mechanics.

    Integration with Classical Methods

    The NIST researchers integrated CAVS sensors with the classical reference standard for gas pressure, known as a dynamic expansion system. By injecting a known amount of gas into a vacuum chamber and slowly removing it at a known rate, the resulting pressure in the chamber can be calculated. The researchers built a high-performance dynamic expansion system capable of handling extremely low gas flows and machined a precise hole for controlled gas removal.

    Realizing CAVS’ Potential

    The development of CAVS represents a significant step forward in vacuum pressure measurements. Its uncomplicated setup and high accuracy make it an attractive option for various applications, including chip manufacturing, quantum computing, gravitational wave detection, and particle accelerators. The simplicity of CAVS, combined with its precise measurements, holds promise in revolutionizing the way vacuum pressures are measured.


    1. How is CAVS different from conventional vacuum pressure measurement methods?
    – CAVS serves as a “primary standard” and provides intrinsic accuracy without the need for calibration to reference pressure readings.

    2. Can CAVS measure lower vacuum pressures than traditional methods?
    – Yes, CAVS can measure pressures as low as a trillionth of Earth’s atmospheric pressure, making it suitable for future chip manufacturing and advanced scientific research.

    3. Does CAVS require calibration or adjustments for accurate readings?
    – No, CAVS operates based on well-understood principles of quantum physics and can provide accurate readings “right out of the box” without additional calibration.

    4. In which fields can CAVS be applied?
    – CAVS has applications in chip manufacturing, quantum computing, gravitational wave detection, particle accelerators, and many other high-vacuum environments.