Abstract
Detection of hydrogen gas is a crucial task for establishing safety and reliability of fuel cells, a key technology for the environment and our society. However, hydrogen is difficult to detect and various hydrogen sensors have many drawbacks. Here we report a novel hydrogen gas sensor, the ball surface acoustic wave (SAW) sensor, using Pd or PdNi sensitive film. The ball SAW sensor is based on a novel phenomenon, diffraction-free propagation of collimated beam along an equator of sphere. The resultant ultra-multiple roundtrips of SAW makes it possible to achieve highest sensitivity among SAW sensors. Moreover, it enables to use a very thin sensitive film, and consequently the shortest response time (2 s) was realized. In terms of the sensing range, it has the widest range of 10 ppm to 100% among any hydrogen sensors including FET or resistivity sensors. The response time was less than 1 s for 3.0% hydrogen concentration in nitrogen gas, evaluated by using a newly developed digital quadrature detector.
| Original language | English |
|---|---|
| Pages (from-to) | 2-6 |
| Number of pages | 5 |
| Journal | Acoustical Science and Technology |
| Volume | 30 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2009 Jan 27 |
Keywords
- Bearing ball
- Gas sensor
- Hydrogen
- Multiple roundtrip
- Naturally collimated beam
- Surface acoustic wave
ASJC Scopus subject areas
- Acoustics and Ultrasonics