Radioluminescent light source for optical oxygen sensors

A self-powered radioluminescent (RL) light source is evaluated as a means of supplying incident radiation for optical chemical sensors. The light source consists of Pm-147 (a beta-emitting radionuclide) and ZnS:Ag phosphor. Blue light (450 nm) is produced following the excitation of ZnS:Ag from beta particles released by the Pm-147, The utility of this source is judged by evaluating the analytical performance of optical oxygen sensors, where the blue light from the RL source excites a ruthenium complex immobilized in a plasticized PVC or silicon membrane, Analytical information is acquired by measuring the magnitude of oxygen-induced fluorescence quenching of the ruthenium complex, ?he resulting RL oxygen sensors show good stability and reversibility, with detection limits of 0.25 Torr in gaseous samples and 0.028 ppm in aqueous samples. Although the RL light source is not as bright as conventional electrical-powered sources, RL sources offer the advantages of compact size, simple configuration, low power consumption, and essentially no photobleaching of the oxygen-sensitive indicator dye, In addition, different phosphors are available to provide a variety of emission:wavelengths and band-passes over a wide spectral range.