Pyroelectric Detectors in Gas Analysis
A large number of gases absorb infrared radiation by intramolecular vibrations. For each specific material, the absorption intensity depends on the wavelength of the infrared radiation. This principle uses a non-dispersive infrared gas analyzer (NDIR gas analyzer) for gas analysis. The analyzer consists of an electronically or mechanically modulated infrared source, a sample cell through which the gas flows to be measured, and a pyroelectric detector.
In the detector cap, a narrow band pass filter (NBP Filter) is integrated, whose pass band corresponds to the absorption wavelength of the target gas. With the thermal detector, the transmission of the measured gas mixture is determined in a defined arrangement. If the gas being searched for is not present, most of the infrared radiation will reach the detector and the signal will be at its maximum. If the concentration of the gas increases, absorption will also increase according to Lambert-Beer's law, and the signal will reduce accordingly.
This concept finds itself again in standard InfraTec infrared filters with a center wavelength (CWL) of 4.27 µm and a half power bandwidth (HPBW) of 170 nm are suitable for the measurement of carbon dioxide (CO2), for example.
NDIR gas analysis cannot resolve complex forms of absorption bandwidths. Instead it uses an averaged signal measurement within the filter pass band. With this, you now have a manageable, long-time stable and continuously operating measurement method for industrial gas analysis at your disposal. Gas identification and transverse sensitivity of gas mixtures often require spectral multi-channel evaluations.
The classic gas analysis setup with filter wheel and/or mechanical chopper requires relatively fast (> 200 Hz) pyroelectric detectors with strong output signals. For this purpose, we offer multiple types with integrated JFET or CMOS operational amplifiers and pyroelectric elements, which are wired up for current mode operation.
Pyroelectric Detectors for Gas Analysis
a measuring channel, high power, temperature compensation, reduced acceleration response, single or split power supply
a measurement and a reference channel, temperature compensation, single or split power supply
Case Studies about Pyroelectric Detectors in Gas Analysis
Technical Article: Low Cost Optical Electronic Nose for Biomedical Applications
Article about the development of an optical-electronic nose with a non-dispersive infrared sensor (NDIR), which is to be aimed at healthcare applications.
Technical Article: Use of Multi Channel Detectors and Infrared Emitters in Gas Analysis
The detection and concentration measurement of gases is a standard procedure in the medical and industrial area worldwide. But what needs to be observed for the selection of components and what do multi channel detectors and infrared emitters have to do with this?
InfraTec offers five different product groups including approximately 50 standard pyroelectric detectors. Choose your suitable infrared detectors with the help of our detailed detector search.