Multi-pixel photon counters (MPPCs) with large detection areas of 1350m are implemented as detectors. As a result, the sensitivity of the sensor is strongly increased. This gain in sensitivity is primarily achieved through two characteristics: first, the operating principle “avalanche breakdown” to detect single photons is used; second, the size of the image projected onto the MPPC is much bigger than the pixel area in competing Raman-Spectrometers resulting in higher photon flux. This combination enables reduction of the required excitation power to levels compliant for operation in potentially explosive atmospheres. All presented experiments are performed with strongly attenuated laser power of 35 mW. These include the monitoring of the analytes ethanol and hydrogen peroxide as well as the reversible binding of to amine. Accordingly, the described embedded sensor is ideally suited as a process analytical technology (PAT) tool for applications in environments with limitations on power input.
Marcel Nachtmann1, Shaun Paul Keck1, Frank Braun1, Hanns Simon Eckhardt2, Christoph Mattolat2, Norbert Gretz3, Stephan Scholl4, and Matthias Rädle1
1Institute for Process Control and Innovative Energy Conversion, Mannheim University of Applied Sciences, Mannheim, 68163, Germany
2tec5 AG, Oberursel/Ts, 61440, Germany
3Medical Research Center, Medical Faculty Mannheim, Heidelberg University, Mannheim, 68167, Germany
4Institute for Chemical and Thermal Process Engineering, Technical University Braunschweig, Braunschweig, 38106, Germany