New technology for high-sensitive fire detectors

Fire detectors save life – however, some models contain radioactive substances. Researchers have developed an alternative. (Photo: Michael Stifter - Fotolia.com)

IMPT | Researchers of the Institute of Micro Production Technology (IMPT) of Leibniz Universität Hannover made a contribution to improve public security with the development of a micro-electron source for high-sensitive fire detectors.

Ion mobility spectrometres are applicable in all fields of gas analysis. They are used especially in breath gas analysis and for the detection of explosives. But they are also well-suited for early fire detection, since they are able to detect gases already in the ignition phase.

For a successful analysis, gas molecules have to be ionized. In the past, this was done by radioactive sources. The researchers have now developed an alternative: Instead, they use a micro-electron source for ionizing the molecules. In a vacuum-sealed housing, electrons released by an emitter move through a thin silicon nitride window chip of approx. 300 nanometres to the analyser.

In contrast to radioactive ionization sources, micro-electron sources can be switched off at any time and need not to be disposed as hazardous waste. Their small size makes them also interesting for use in hand-held devices, for example to detect chemical agents.

by Alexander Kusch

Image gallery for this article

  • Fire detectors save life – however, some models contain radioactive substances. Researchers have developed an alternative. (Photo: Michael Stifter - Fotolia.com)
  • Prototype of a vacuum-sealed housing for a micro-electron source. Later on, the glass cylinder is melted away to seal the housing. (Photo: Alexander Kusch, IMPT)
  • Schematic structure of a micro-electron source: The electrons leave the housing by moving through the thin silicon nitride window chip. (Graphic: Alexander Kusch, IMPT)