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Flame Detector

Highly sensitive GEM based UV flame and smoke detectors

Description

Supersensitive UV flame detectors based on wire- or GEM-type amplification structure were developed at CERN in close collaboration with Ecole des Mines in St Etienne (France) and Oxford Instruments (Finland). In contrast to commercial UV flame sensors, in these detectors either semiconducting solid photocathodes or vapours with small ionization potential are used as main photosensitive elements. As a result, the sensitivity is 100-1000 times higher than the best commercial sensors, depending on a particular design. Wire and GEM-based gaseous detectors operate in proportional mode and can detect various flames, including sparks, in direct sunlight conditions. Combined with compact pulse UV sources they can detect simultaneously not only flames, but also smoke and some dangerous gases, for example benzene or toluene vapours. GEM-based detectors supplied with a lens can also provide information on the position of the flame and smoke. To make the detector robust, modified versions of GEMs were developed and successfully used in the latest designs: ether a so-called thick GEM or a resistive GEM, both manufactured from printed circuit boards.

Area of expertise

Detectors and Instrumentation

Possible applications

Wire and GEM-based gaseous detectors operate in proportional mode and can detect various flames, including sparks, in direct sunlight conditions. Combined with compact pulse UV sources they can detect simultaneously not only flames, but also smoke and some dangerous gases, for example benzene or toluene vapours. GEM-based detectors supplied with a lens can also provide information on the position of the flame and smoke. The new detectors are ideal for spark detection or fire safety survey of large areas: hangars, storage buldings and forests. RETGEM-based detectors ware able to reliably detect a 1,5m3 fire at a ~1 km distance.

Advantages

The structure is produced by the same technology as TGEM and RETGEMs. However, due to the feature of its design (aligned holes without walls), the leakage current is fully eliminated.

Sensitivity is 100-1000 times higher than the best commercial sensors, depending on a particular design.

Limitation

The holes need to be aligned and the distance between plates equal or close to hole diameter, which can be complicated in the case of very small holes and pitch. The same applies to the spacers. However, in some cases the anode can be without holes, simplifying the production.

Intellectual Property Status

International patent application filed.

References

G. Charpak et al JINST 4 P12007, 2009

V. Pekov et al., ArXiv :1305.0719, 2013

J.M. Bidault et al., NIM A580, 2007, 1036

L. Periale et al.,NIM A572, 2007, 189

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