SERVOPRO Servomex Plasma

Plasma delivers a highly specific, stable gas measurement

Servomex’s Plasma emission detection technology was developed to provide a safer alternative to flame-based sensing for hydrocarbon analysis. Delivering ultra-low measurements, it is used in our SERVOPRO Plasma, Chroma, NanoChrome, and NanoChrome ULTRA analyzers.

A discharge process occurs when sufficient energy is provided to ionize a gas stream. The resulting plasma consists of free electrons, ions, neutral molecules, and high-energy photons in a continuous state of ionization and recombination.

When energized by an external, alternating high-voltage field, gases flowing in a Dielectric Barrier Discharge (DBD) glow plasma produce intense emission spectra which relate directly to their unique molecular bonds.

The optical emission spectroscopy (OES) method combines precision optical filters and detectors to provide a highly selective gas measurement.

Our DBD plasma sensor consists of a custom quartz cell with transparent windows fitted with electrodes powered by a controlled radio frequency (RF) electromagnetic field. Multiple OES detector assemblies surrounding the quartz cell make selective measurements of emitted spectra of multiple gas species at the same time.

This highly sensitive and selective speciation of gases enables measurement of trace parts per billion (ppb) of gases.

Related and alternative technologies

Plasma sensing can be used together with Gas Chromatography techniques to deliver highly sensitive measurements down to ppb levels. However, this sensitivity means that it is only suitable for trace analysis applications.

Key applications


Medical gases

Air separation units

Key benefits

Safer and more stable than competing technologies

Reliable, gas-specific selectivity

No sensor maintenance requirements

Ideal for

Safe, stable trace-level analysis of hydrocarbons as impurities in Pure Gas (P-Gas) for semiconductor fabs.

Explore the Plasma analyzers we have for your process

Learn more about all our gas analyzer solutions that use this sensor technology.

Search Servomex Plasma analyzers

Refine by search term



The Chroma is optimized to specific background gases to ensure optimum performance for your application.

  • Versatile, ultra-accurate trace gas analysis
  • Choice of non-depleting sensor technologies
  • Cost-effective solution for process control or quality monitoring
  • Works in a wide range of background gases
  • Compact 4U rack-compatible design
  • Flexible communication options



Incorporating the latest advances in gas sensing and signal processing methodology, the NanoChrome revolutionizes ultra-trace purity measurements.

  • Ultra-trace purity measurements in UHP gases
  • Designed for semiconductor manufacturing
  • Uses advanced Plasma Emission Detector sensor
  • Sensitive ProPeak software for high accuracy
  • Removes the need for flammable fuel gas
  • Comprehensive reporting and statistical analysis

NanoChrome ULTRA


Using proven ultra-trace sensing, the NanoChrome ULTRA conquers the most stringent demands of the semiconductor industry, delivering a cost-effective solution compared to competing technologies.

  • The top choice for ultra-trace purity measurements
  • Designed for the semiconductor wafer industry
  • Superior measurements of ultra-high-purity gases
  • Highly specific, non-depleting PED sensing
  • ProPeak filtering for highly sensitive measurements
  • Removes the need for flammable fuel gas



The Plasma delivers an accurate, highly stable and reliable measurement, with high sensitivity in the 0-1ppm range.

  • Analyses nitrogen in argon
  • Specifically designed for ASU plants
  • Unsurpassed stability and selectivity
  • High-specification Plasma Emissions Detector
  • Standard or high-purity setting modes
  • Reliable and accurate continuous monitoring

Learn more about this technology and all the others we provide – download the magazine

Get a free copy of our special Expert Solutions magazine focusing on our complete range of sensing technologies. It’s available to download now.

Need more advice? Contact the gas analysis experts today

If you still need guidance to find the best solution for your process, we’re here to help. Our expert team combines applications knowledge with extensive experience and deep understanding of the sensing technologies available. We’ll help you find the solution that meets your unique needs.

© Copyright 2024 - Servomex is a Spectris company.
Click here to download your selected documents