Glass envelope UV-sensitive flame detectors

The need for fast-response low-voltage flame sensors, able to operate for long periods in ambients presenting a wide range of temperatures, prompted the construction and testing of gas amplification UV-photosensitive detectors utilizing 9741 glass envelopes and a variety of gas fills and electrode and getter materials. Addition of 1 mole percent H2to a He gas fill reduced the required minimum time between counts for a given sensor operating voltage without significantly changing the threshold voltage. All sensors with H2additive ultimately became solar sensitive. Sensors performed well at temperatures as high as 350°C.