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Resistive gas dosimetry : A novel measurement method to measure small gas concentrations and quantities both accumulative and timely resolved

Title data

Moos, Ralf:
Resistive gas dosimetry : A novel measurement method to measure small gas concentrations and quantities both accumulative and timely resolved.
Event: “Friday Talk”, Micro and Nanosystems Seminar , 22.3.2023 , ETH Zürich, Switzerland.
(Conference item: Other Event type, Speech )

Abstract in another language

With conventional conductometric gas sensors, the conductivity of the sensitive material depends on the actual concentration of the component to be measured (i.e., the analyte). If it is intended to apply them to measure smallest concentrations of a gaseous analyte, the classical resistance measurement using metal oxide gas sensors reaches its limits. The response time may be short and the sensitivity high, but the recovery time is very long. Determining hourly mean values with such a method requires an integration of the sensor signal over an hour; this leads to large errors. Resistive gas dosimeters could offer a remedy. They follow an integrating measurement principle. The sensitive material stores the gas component (it accumulates it), changing its conductivity or electrical impedance as linearly as possible with the amount of the stored component. Two basic application modes appear possible. Due to the integration that takes place in the material, the sensor conductance or impedance is directly proportional to timely averages, e.g., to hourly mean values (with an integration time of one hour). When the material starts to saturate, a deviation from linearity occurs. Then, the sensor material has to be regenerated (mostly thermally). Due to the linearity, the exact zero point hardly matters. Thus, zero drifts can be eliminated. Advantageously, due to the timely accumulation of the analyte, gas concentrations in the sub-ppm or ppb range can be detected. In the lecture, applications at an operating temperature of about 300°C for the detection of nitrogen oxides both in exhaust gas (ppm range) and in much lower concentrations in ambient air (ppb range) will be presented first. Regeneration is performed thermally. Then gas dosimeters for operation at room temperature with UV regeneration are discussed. How gas dosimeters can be used as GC detectors will be shown at the end of the presentation.

Further data

Item Type: Conference item (Speech)
Refereed: Yes
Institutions of the University: Faculties > Faculty of Engineering Science
Faculties > Faculty of Engineering Science > Chair Functional Materials > Chair Functional Materials - Univ.-Prof. Dr.-Ing. Ralf Moos
Profile Fields > Advanced Fields > Advanced Materials
Research Institutions > Research Centres > Bayreuth Center for Material Science and Engineering - BayMAT
Result of work at the UBT: Yes
DDC Subjects: 600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited: 11 Apr 2023 06:02
Last Modified: 11 Apr 2023 06:02