High-Accuracy Miniature Dew Point Sensor and Instrument

This paper introduces a novel dew point sensor that is characterized by miniature size and accuracy that matches the well-known and much larger chilled mirror sensors. The new sensor is based on the beta voltaic principle, a relatively new principle of physics. It consists mainly of a radioactive beta-particle source and a silicon p-n junction. If no water condensation exists on the surface of the p-n junction, the beta particles enter the junction and generate a steady dc voltage. Once a condensed layer of water forms, the beta particles are blocked and the voltage produced by the p-n junction falls. The sensor will be very useful in new instruments and industrial applications that demand a miniature and highly accurate dew point sensor.