Please update your browser. It looks like you are using an old version of the Microsoft Edge browser. To get the best experience with the Pfeiffer website, please update your browser.

This way
Contact Login to portal
Global
pvweb_221_allapplicationmotifs_1200x675_0002_ion_thruster_chamber

Generation of Ultra-High Vacuum

Achieving ultra-high vacuum (UHV) requires more than just a good vacuum pump – it involves system design, materials, and expertise. Pfeiffer delivers the complete solution.

Challenges in achieving ultra-high vacuum

To generate ultra-high vacuum (UHV) – typically defined as pressures below 10⁻⁷ hPa (mbar) – a coordinated and precise system design is essential. Even the smallest sources of contamination can have a major impact: A single fingerprint left inside a chamber can lead to hours of additional pump-down time. This level of sensitivity highlights just how clean, controlled, and well-planned a UHV system must be from the very beginning.

Key questions to consider during planning include:

  • Material selection: How does material selection impact the achievable vacuum level and long-term stability?
  • Chamber design: What role do vacuum chamber design and surface treatment play in minimizing gas load and avoiding trapped volumes?
  • Leak rate management: How can potential leaks be identified and eliminated during system assembly?
  • Pump configuration: What pump technology and compression ratios are required to reliably reach UHV conditions?

Find all the answers and further information in the FAQ.

System design

Vacuum applications

Success stories

Effects on ultra-high vacuum

placeholder
In ultra high vacuum (UHV) environments, gas behavior changes significantly. Several physical effects must be taken into account:

  • Adsorption: Gas molecules attach to chamber surfaces.
  • Absorption: Gases are trapped in the material itself, often following adsorption.
  • Desorption: Previously trapped gases are released into the vacuum environment.
  • Permeation: Gases diffuse through solid materials into the vacuum environment.
  • Leakage: External gases enter through imperfections or poor sealing.
  • Virtual leaks: Trapped volumes or improper welds slowly release gas, mimicking real leaks.

System design in ultra-high vacuum environments

Generating ultra-high vacuum (UHV) requires more than just powerful vacuum pumps – it is about getting every detail right.

From minimizing outgassing in vacuum chambers to choosing the right combination of turbomolecular vacuum pumps, dry backing pumps, and precision gauges, system architecture plays a decisive role.

Compare matching products
  • ATH-M turbomolecular vacuum pump

    ATH-M turbomolecular vacuum pump

  • vacuum_chamber_1

    Vacuum chamber

  • getMedia
  • getMedia
  • getMedia

    ATH-M turbomolecular vacuum pump

  • getMedia

    Vacuum chamber

  • getMedia
  • getMedia

Suitable components include:

  • Ultra-high vacuum (UHV) chambers
  • Turbomolecular vacuum pumps
  • Backing pumps
  • Accurate pressure and gas monitoring
  • Reliable sealing and leak protection

For a full breakdown of critical components and how they work together, see our FAQ section.

Need help selecting the right components for your ultra-high vacuum (UHV) system? Get in touch with our vacuum experts.

Insights into real-life applications and requirements

Ultra-high vacuum (UHV) is not limited to basic research. It is an enabling technology across several sectors. Get more insights into real-life applications and requirements:

Applications and industries using ultra-high vacuum

  • High-energy physics: Require ultra-stable vacuum conditions for beam guidance, acceleration, and collision experiments.
  • Plasma physics and fusion experiments: Depend on clean, high-vacuum environments to minimize contamination and manage high-energy plasma interactions.
  • Space research and satellite simulation: Simulate outer space vacuum and extreme temperatures for satellite and spacecraft component testing.
  • Mass spectrometry and surface science: Mass spectrometry needs clean, stable UHV for precise ion detection and surface composition analysis (e.g. XPS, AES).
  • Photonics: Use UHV to reduce noise and scattering in laser systems, detectors, and high-voltage setups.

Interested in how ultra-high vacuum (UHV) applies to your research or production process? Contact us for tailored system recommendations.
Matching products
pvweb_221_allapplicationmotifs_1200x675_space_simulation

Learn more about UHV

How to generate ultra-high vacuum (UHV)?

Achieving ultra-high vacuum (UHV) starts with a solid understanding of vacuum physics – including vacuum levels, pressure dynamics, and gas behavior. Explore our expert-led video series for a step-by-step walk-through of UHV system design, chamber preparation, and pump selection.

Watch the full video playlist

  • getMedia
  • getMedia

What are the key components in a UHV system?

A standard ultra-high vacuum (UHV) setup begins with a dry backing pump (second stage) to lower the pressure to around 10⁻³ hPa (mbar). A high or ultra-high vacuum pump (first stage), such as a turbomolecular vacuum pump, then takes over to reach the final operating pressure.

    • Vacuum chambers: Made from austenitic stainless steel to reduce outgassing and withstand high temperatures. See more in our section on vacuum chambers.
    • High vacuum pumps: For light gases like hydrogen or high outgassing loads, turbomolecular vacuum pumps (e.g. HiPace H series) offer compression ratios ≥ 10⁷ – essential for reaching and maintaining UHV.
    • Backing pumps: Dry vacuum pumps such as scroll (HiScroll), diaphragm (MVP), or multi-stage Roots vacuum pumps (ACP) are oil-free, quiet, and require little maintenance – ideal for clean UHV environments. Rotary vane vacuum pumps (e.g. DuoVane) are also used where compactness and robustness are key.
    • Vacuum gauges: Ionization and cold cathode gauges enable accurate pressure monitoring – essential for process control and system diagnostics.
    • Residual gas analyzers (RGA): Tools like PrismaPro analyze gas composition in real time to detect contamination or leaks and verify system cleanliness.
    • Metal seals and CF flanges: Provide tight, temperature-resistant sealing with minimal permeation – critical during bake out or thermal cycling.
    • Valves and accessories: Ensure safe operation, isolate chambers, and support flexible system control. Smart valve setups protect components during venting or emergency conditions.
    • Leak detection: After installation, helium leak detection is essential to verify system tightness. Even tiny leaks can prevent UHV conditions. Proper testing ensures the system meets required leak rate specifications before bake out and final pump-down.

    Compare matching products

    What materials are best for an ultra-high vacuum chamber?

    Material choice affects everything from vacuum integrity to long-term stability. It is not just about low outgassing – several factors matter:

    • Gas tightness: Low vapor pressure and minimal internal gas content.
    • Mechanical strength: Stability under vacuum without deformation.
    • Outgassing rate: Minimal surface and bulk gas release.
    • Thermal compatibility: Matching expansion rates (e.g. stainless steel and copper).
    • Fabrication practicality: Easy to process and widely available.

    Austenitic stainless steel remains the standard for UHV systems due to its reliability and bake out performance.

    Need support choosing the right materials? Talk to our experts.

    How does UHV compare to high vacuum (HV) and extreme high vacuum (EHV)?

    Vacuum systems are typically categorized by the pressure ranges they achieve. Each range has specific technical requirements and serves different applications:

    Vacuum range
    Pressure level
    High vacuum (HV)
    10⁻⁴ hPa to 10⁻⁷ hPa (mbar)
    Ultra-high vacuum (UHV)
    Below 10⁻⁷ hPa (mbar)
    Extreme high vacuum (EHV)
    Down to 10⁻¹² hPa (mbar) or lower


    High vacuum is often sufficient for industrial processes. In contrast, UHV and EHV demand specialized materials, sealing techniques, and advanced pumping systems.

    The ultimate pressure of turbomolecular vacuum pumps is in the lower UHV range and, in optimized configurations, even in the EHV range. For higher EHV conditions, additional technologies are required – such as ion pumps, titanium sublimation pumps, and non-evaporable getter (NEG) pumps.

    Why are operating pressure and compression ratio important?

    Understanding your required operating pressure (pₒ) is one of the most critical steps in UHV system design.

    It defines:

    • The vacuum level your system must sustain during operation.
    • The vacuum pump type and size.
    • Material and sealing strategies.


    Designing without a clear operating pressure target often leads to systems that are either overengineered and costly – or underperforming and unstable. Equally important is the compression ratio (K₀) of the turbomolecular vacuum pump, especially when handling light gases like hydrogen. Based on Gaede’s formula, this ratio reflects the ability of the vacuum pump to reduce gas pressure at each stage. The lower the target pressure, the higher the compression ratio needed.

    Learn more in our vacuum technology book

    Together, operating pressure and compression ratio are essential design parameters for reliably achieving ultra-high vacuum (UHV) conditions.

    Watch our videos about basics of vacuum

    Why does conductance matter?

    In the molecular flow regime, system conductance – the ability of vacuum lines to allow gas flow – becomes critical. Long or narrow connections can significantly reduce effective pumping speed. An optimized system geometry ensures vacuum pumps operate at their full potential.

    Why choose Pfeiffer turbopumps for UHV related applications?

    Since 1955, Pfeiffer has set the benchmark in turbopump technology – combining precision engineering, innovation, and decades of experience. Our turbomolecular vacuum pumps, including the laser-balanced HiPace series, are trusted worldwide for their long service life, low vibration levels, and consistent performance even in demanding UHV and EHV applications.

    Our expertise ensures you get the right turbopump for your process – whether you are dealing with light gases like hydrogen or need a compact solution for integration into analytical devices.

    Curious about how a turbopump works? Explore the working principle and learn more about our turbopumps.

    What are the most common mistakes that prevent reaching UHV and how can they be avoided?

    Achieving UHV requires attention to detail throughout system design and installation. Common issues that prevent reaching ultra-high vacuum include:

    • Elastomer seals or plastics allow gas permeation, degrading the vacuum level over time.
    • Poor or twin welds can create virtual leaks, trapping gas that gradually escapes.
    • Skipping bake out procedures leaves surface-bound gases (especially water vapor) that prevent pressure from dropping.


    How to avoid them

    • Use all-metal CF seals for leak-tight connections.
    • Minimize non-metallic components inside the vacuum system.
    • Ensure proper internal welding with no blind spots or cavities.
    • Always include a controlled bake out step in your commissioning process.

    Well-planned UHV systems – supported by reliable components and expert guidance – ensure long-term stability and repeatable performance.

    Customer success stories

    Ultra-high vacuum (UHV) systems are essential in many fields beyond basic research. Here is how UHV enables demanding environments and how Pfeiffer contributes to their success:
    thumb_vtforrandd

    The marketing-cookies have to be accepted to watch this video.

    Allow all cookies

    Collaborative vacuum solutions for particle accelerators

    TU Darmstadt

    We supported the installation of an EBIS ion source at the Technical University (TU) of Darmstadt, Germany, for generating highly charged ions used in laser spectroscopy experiments. Our system expertise together with our integration know-how ensure precise beamline conditions and reliable performance tailored to the research setup.

    Matching products
    thumb_nail_space_research_drl

    The marketing-cookies have to be accepted to watch this video.

    Allow all cookies

    Vacuum technology in space research

    DLR Cologne

    To simulate the vacuum and temperature extremes of outer space, the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR) relies on robust vacuum and measurement solutions. Pfeiffer delivered high-reliability components and technical consulting for safe and repeatable test conditions – essential for preparing hardware for missions aboard the ISS and other platforms.

    Matching products
    pvweb_224_leak_detection_of_systems_spraying_uhv_wendelstein

    Plasma physics

    Wendelstein 7-X

    For the Wendelstein 7-X fusion experiment, UHV requirements included extremely low leak rates, high thermal stability, and long-term vacuum integrity. Pfeiffer worked closely with project engineers to select, verify, and deliver suitable technologies – helping meet the strict operational demands of this large-scale research facility.

    Matching products