Technology - Photo-Acoustic Spectroscopy
Photo Acoustic Spectroscopy (PAS) is a flexible technology that enables the detection of a wide range of gases at trace level and is compatible with various applications requirements and markets. This technology is integrated in all Omnisens Trace Gas Analyzers.
Photo Acoustic Spectroscopy technique is based on the ability of gas to absorb infrared light at specific wavelength and retransmit the absorbed energy into sound waves which can be detected with high sensitivity microphones. PAS combines the selectivity of Infrared Red spectroscopy with the sensitivity of acoustic detection.
Specific advantages of Omnisens technique over other measurement techniques are:
- PAS is a “zero-baseline” technique: zero gas concentration gives no signal; while the acoustic signal being directly proportional to the measured concentration over a large measurement range.
- An extremely low detection limit (in the part-per-billion range) for several molecules (ammonia, ethylene, sulfur hexafluoride, hydrochloride, hydrofluoride, water, methane, etc.).
- Real-time measurements and continuous uninterrupted measurements at the lowest concentration thanks to dedicated sampling technique and materials.
- The monitoring of gas at ppb or even sub-ppb requires very specific sampling techniques and appropriate materials. OMNISENS has developed several unique sampling schemes in relation with application requirements in order to guarantee best possible monitoring performances.
In 2001, Omnisens introduced the first laser-based resonant PAS measurement system commercially available on the market by launching the TGA300-Series ammonia trace gas analyzer with sub-ppb sensitivity for semiconductor manufacturing plants. On-going developments are aiming at offering a comprehensive range of trace gas analyzer for various applications and based on Omnisens highly sensitive technology.
detection limits
Please contact Omnisens to obtain lowest achievable detection limits of a target gas in your complex carrier gas composition.