Chemical Leak Sensors

We propose a novel approach for the development of a highly-sensitive chemical leak sensor for the detection of Cl2, NH3, O2, I2 and H2O2 at the part per million (ppm) level. Our device approach utilizes Raman spectroscopy for species identification, diode lasers as the Raman pump source, high finesse cavities (HFCs) for passive optical pump enhancement, and an integrating sphere for efficient signal gathering. The proposed device is capable of generating and capturing 50,000 to 100,000 photons/sec for all the gases at a concentration of 1 ppm. These large photons rates allow for species detection with low-cost, highly reliable photo-diode or avalanche photo-diode arrays. Specifically, the detection system will use a commercially available diode laser a high finesse cavity in an integrating sphere with the laser diode emitting at 790 nm passively locked to the cavity. Due to the use of commercial laser diodes system lifetimes on the order of 10,000 to 50,000 hours is predicted.