Surface acoustic wave hydrogen sensor

A new hydrogen sensor based on the velocity changes of surface acoustic waves (SAW) due to hydrogen absorption or desorption in a palladium thin film is described. A dual SAW delay-line is the key element of the device: one delay path is coated with the selective sorbant film, the other one is uncoated and is used as a reference in order to minimize the effects of both temperature and pressure variations. Response time, sensitivity and time stability of the device have been evaluated and first results are reported. © 1983.