Optical, Evanescent Wave Missile Fuel Leak Detector

Liquid-fueled missiles are stored in canisters, flight-ready, with batteries charged and fuel tanks full. In peacetime, these missiles may stay in the canisters for six years or more. The Navy therefore needs sensors to detect leakage of missile fuel and battery acid. Physical Optics Corporation (POC) will develop a novel optical evanescent wave sensor to detect fuel leakage. Unlike other distributed optical fiber sensors, POC's sensor will produce stronger interaction of the core guided light with fuel molecules, adsorbed to the sensor, after leakage. The sensor is intrinsically safe in potentially explosive environments because it is entirely fiber optical -- no electric sparks are possible. POC expects sensitivity to 100 ppm of JP family hydrocarbons. We will construct a working system in Phase I and test it for the presence of hydrocarbons, battery acid, and moisture. POC's proposed sensor will reproducibly detect missile fuel in both liquid and vapor forms, operate perfectly while the missile is being transported, detect battery acid, operate under wide range of temperature and humidity conditions, have six years plus service life, be mass producible, and be low cost.