Beam splitter detectors for gas analysis

As a part of gas detection instruments, infrared detectors are dedicated to the wellbeing of humans and environment. Multi channel detectors with beam splitters by InfraTec allow for very precise gas analysis, particular in gas detection technology. This ability makes them a perfect fit for measurement or testing tasks in safety technology. Actually, their measuring performance characteristics experienced crucial improvements over recent years. That’s why they can be found utilised not only in stationary and mobile analysing instruments in industrial environments with adverse ambient conditions but also in the field of process instrumentation supporting quality assurance and in hospitals  in measuring instruments for anesthesia monitoring.

Accurate and stable measurement results over the long term
Unlike conventional multi channel detectors, beam splitter detectors only have one single aperture opening. Thus, major parts of the incoming radiation impinge vertical to the pyroelectric crystal, which allows for very accurate measurement. Hence, a gas cell with an effective diameter of just 2.5mm is sufficient. Apart from an accelerated exchange of gas, this results in very low dead volumes of the measuring system. Measurement devices equipped with the detector can be correspondingly smaller. The permanently stable signal ratio between the individual channels ensures a high degree of measurement accuracy. This is because mechanical expansions in the optical system of the measurement device, ageing effects or any possible contamination in these detectors are already accounted for before the beam is split and thus affect all channels equally.

Reflection beam splitters – a specific kind of beam splitters
The split of incoming radiation beams into various parts takes place inside the detector. The beam splitters used by InfraTec in multi channel detectors are solely reflection beam splitters. That means they reflect the incoming radiation in various directions respectively. These optical components consist of highly reflective gold plated microstructures. The radiation entering through the aperture opening of the detector is split into several radiation beams of equal intensity but in different, predefined directions within the detector based on the architecture of the innovative microstructure inside. Each of the beams impinges on a corresponding pyroelectric sensor element with an upstream optical filter. The microstructures vary according to the detector type. In four channel detectors these resemble four-sided micro-pyramids, whereas in dual channel detectors these are V-shaped grooves.

Combining stable measurement characteristics with long-lasting design, beam splitter detectors are suitable for integration into portable gas detection instruments as well as fixed installed gas detection systems. They enable for continuous 24/7 operation.

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