Gas Multiplication UV Sensors for Fire and Explosion Detection.
Final rept. 1 Mar-31 Jan 69,
GENERAL ELECTRIC CO SCHENECTADY NY RESEARCH AND DEVELOPMENT CENTER
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A highly developed titanium-fosterite tube envelope technology is being used to construct ultraviolet-sensitive gas multiplication phototube flame detectors which can operate in air over a wide range of temperatures up to 1000F. A method for sealing sapphire windows to these tube envelopes has been developed. The flame detector tubes utilize single crystal molybdenum photocathodes and molybdenum anode-light collectors. Tests made in demountable gas-vacuum system established the gas combination, 99.5 percent helium plus 0.5 percent argon at a room temperature pressure of 100 torr, as a proper fill for this sensor tube. Electronic quenching is used. These sensor tubes respond to ultraviolet light of wavelength less than 2850 angstrom and have operating voltage ranges of 10 volts, centered near 170 volts. The tubes exhibit fast pulse rise times and minimum times between pulses of less than a millisecond. In air a sensor tube at 1000F yielded a background count of 6 counts per minute, and a counting rate of 132 counts per minute when exposed, at a distance of 20 feet, to a 4-inch pan fire of burning No. 640 jet fuel. Author
- Safety Engineering
- Ultraviolet Detection and Detectors