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Wi.Tec-Sensorik · The Gas Measurement Company
SPECTRO.sens (Intro)
SPECTRO.sens
SPECTRO.sens
Laser-Based Gas Analysis for CH₄
– ppm-accurate, low-drift, low-maintenance.
The new gas measurement module from Wi.Tec-Sensorik. Based on Tunable Diode Laser Absorption Spectroscopy (TDLAS). Designed for OEM applications where NDIR reaches its limits.
0,1 ppm
Detection Limit
± 2 ppm
Accuracy
< 5 s
T90 Response
Motivation
Why another measurement module?
Because NDIR reaches its limits in certain applications.
NDIR optical measurement systems have been a core part of our portfolio for years and work reliably in many applications. In some areas, however, the requirements for detection limits, long-term stability and selectivity continue to rise — that is where SPECTRO.sens comes in.
Typical Problems in NDIR Gas Analysis
- Cross-sensitivities to water vapour and other hydrocarbons that distort the signal.
- Drift due to ageing of the IR source and optical contamination — regular zero-point adjustment required.
- Trade-off between range and resolution: ppm measurements and vol.% measurements often require separate modules.
- Maintenance effort: regular calibration, purge gas, zero-point control.
What SPECTRO.sens does differently
- No cross-sensitivities to H₂O, CO₂, N₂O or other hydrocarbons — even at 100 vol.% ethane, propane or butane.
- Self-referencing at every scan: zero value U₀ is measured outside the absorption line. Drift is effectively compensated.
- One range for everything: 0–10,000 ppm or 0–10 vol.% with constant accuracy across the entire range.
- Low-maintenance: zero-point adjustment only after several months, endpoint check once per year.
Features
Designed for OEM Integration.
Built for Quality and Stability.
Modular design, minimal adhesives, high-quality components. Integrated into a thermostatically controlled enclosure that simplifies deployment in demanding systems.
TDLAS Measuring Principle
Tunable laser diode in the NIR range. Scanning a CH₄ absorption line with high selectivity.
High Long-Term Stability
Zero-point stability ± 2 ppm per month. No continuous zero gas required. Reference is measured automatically.
Fast Response Time
T90 < 5 s at 1 l/min. Update rate 1 Hz. Suitable for continuous monitoring and dynamic processes.
Thermostatically Controlled at 50 °C
Heating elements stabilise the optical bench. No condensation in the analysis cell. Pressure and temperature compensation integrated.
RS232 + CAN
Standardised data communication. 24 VDC ± 2.5 V supply. Gas connection 4/6 tubing. Directly integrable into existing OEM systems.
Platform for Further Gases
Following CH₄, planned: H₂O, NH₃, CO and O₂. Same hardware platform, adapted laser configuration.
Measuring Principle
Tunable Diode Laser Spectroscopy, simply explained.
Gas concentration is determined according to Beer-Lambert’s Law. The laser scans an absorption line in the NIR band — the line itself provides the signal, the adjacent region provides the reference.
Tune the Laser
The tunable laser diode is scanned via the diode current across a CH₄ absorption line in the NIR band.
Beam through the Cell
The laser beam passes through the analysis cell twice (double optical path length 2·L) and hits the radiation detector.
Signal and Reference Simultaneously
Each scan measures both inside and outside the absorption line. The zero value U₀ serves as automatic reference.
Calculation and Compensation
Concentration is calculated from U(c), U₀, path length L and absorption coefficient α. Pressure and temperature compensation run automatically.
Application Fields
Where SPECTRO.sens excels.
Wherever NDIR reaches its limits — where high selectivity, low detection limits and long-term stability are required – SPECTRO.sens is the right choice. Complete specifications and application details are available in our whitepaper.
Biogas Plants
Continuous process monitoring of methane content in raw biogas. High selectivity against CO₂, H₂S and water vapour — typical accompanying substances in biogas.
LDAR / EU Methane Regulation
Since 2024, oil, gas and mining operators in the EU are required to conduct regular leak surveys (LDAR). SPECTRO.sens delivers the required measurement accuracy at ppm level.
Wastewater Treatment Plants
Monitoring of digester gas production, methane recovery from sewage sludge. Low-maintenance long-term measurement without regular zero-point calibration — ideal for unattended stations.
Landfills
Mandatory monitoring of landfill gas emissions at the surface and in degassing systems. Detection of diffuse methane emissions already at ppm level.
Mining & Tunnelling
Methane monitoring in underground workings and tunnels. Since 2025, flaring of mine gas is banned in the EU — precise measurement technology is mandatory.
Industrial Safety
Gas warning systems, explosion-proof applications, monitoring of utility shafts and technical rooms. Fast T90 time under 5 s for safety-critical applications.
Agriculture & Emission Monitoring
Measurement of methane emissions from slurry systems, stables and agricultural biogas processes. Growing market driven by EU emission reporting obligations.
Food & Packaging
Protective gas monitoring in MAP packaging lines, leak detection on gas pipelines in production facilities. No cross-sensitivities to water vapour or CO₂.
Preliminary
Available SPECTRO.sens OEM-Modules
Prototype Stage
Your Application Could Be Part of the Next Step.
SPECTRO.sens is currently in the prototype stage. We are working with selected applications and welcome early discussions with OEMs, developers and integration partners.
Discuss your application — tell us which gas, measurement range and application you have in mind.
Explore what’s possible — non-standard gases and measurement ranges are part of the conversation, especially at this stage.
Talk directly to our experts — your inquiry goes straight to engineering and sales. No call centre, no detours.
Developed & Made in Wesel — sensor development and manufacturing in Germany.
Available Documents
SPECTRO.sens Inquiry
Tell us what you need. We will get back to you with an initial assessment within two business days.