• Reliable gas detection from a distance and even in daylight

Duisburg– The Fraunhofer Society is making hydrogen applications safer and more cost-effective: In the collaborative project RADIANT, the Fraunhofer Institute for Microelectronic Circuits and Systems IMS, the Fraunhofer Institute for Applied Solid State Physics IAF, and the Fraunhofer Center for Applied Photonics CAP (Glasgow, UK) are developing a novel, compact Raman LiDAR system. It reliably detects gas leaks, particularly hydrogen leaks, from a distance, even under challenging environmental conditions. For operators of energy plants and industrial processes, this means: early fault detection without endangering personnel, continuous monitoring, and scalable solutions that can be successfully transferred from the laboratory to real-world plant operation.

The safe use of hydrogen is considered key to the energy transition, but it presents industry and infrastructure operators with new challenges. Hydrogen is colorless and odorless and exhibits hardly any optical absorption characteristics. Early, reliable detection of leaks from a safe distance is therefore essential, for example in power plants, production facilities, or pipelines.

Reliable gas detection from a distance and even in daylight

This is where Raman LiDAR technology comes in: It uses the characteristic Raman scattering of molecules to uniquely identify different gases and precisely determine their position via time-of-flight measurements. The challenge lies in the weak optical signals, which are often only on the order of single photons, especially during measurements outdoors and in bright sunlight.

However, existing Raman LiDAR systems are often designed for a limited number of predefined molecules. RADIANT (»Raman Atmospheric DetectIon And raNging Technology«) pursues a new approach: By using linear detector arrays, the existing filter-based spectral partitioning is replaced. This allows for significantly greater molecular flexibility and paves the way for universal molecule detection. The system operates in the solar-blind UV-B and UV-C ranges. In these ranges, solar background radiation is greatly reduced, enabling measurements in daylight and significantly increasing sensitivity.

Contribution from Fraunhofer IMS: highly sensitive detectors for practical application

Fraunhofer IMS contributes its expertise in the development of back-illuminated silicon photomultiplier tubes (BSI-SiPMs) with increased UV sensitivity to RADIANT. "The detectors are specifically optimized for the requirements of time-resolved Raman measurements and enable the detection of extremely weak signals with simultaneously high temporal resolution," explains Dr. Maren Kasischke, Head of Industry at Fraunhofer IMS.

A key development step is the readout circuit for up to 32 channels, which allows parallel and rapid processing of all spectroscopic signals. This makes it possible for the first time to acquire Raman spectra with high temporal and spectral resolution and to flexibly adapt them to different molecules.

As a complementary approach, Fraunhofer IAF is developing a cost-effective, large-area, and sunblind detector technology for future use in handheld devices with adapted system performance. Fraunhofer CAP is leading the project and contributing its many years of experience in the development of Raman LiDAR systems. The focus is on the reliable remote detection of gases and the integration of all components into a practical overall system.

Added value for industry, operators and technology partners

For operators of energy and industrial plants, this technology opens up new possibilities for the continuous monitoring of infrastructure, particularly in the context of a growing hydrogen economy. The system's enhanced molecular flexibility allows for the detection of different gases without requiring the sensors to be pre-defined for specific substances. At the same time, the project aims to significantly reduce the size, complexity, and cost of the systems, thus enabling compact, mobile, or permanently installed solutions for diverse application scenarios.

RADIANT also offers clear added value for industrial and development partners. The detector and readout technologies developed in the project form the basis for application-oriented demonstrators that can be transformed into marketable products in the future. The Fraunhofer consortium thus supports companies in developing innovative safety and monitoring solutions and in unlocking new applications along the energy, process, and safety value chains.

Source:  Fuel Cells Works