Kcnb: a novel potassium channel protein

摘要

The present invention relates to a device for accomplishing noise reduction in a photoacoustic gas detector (1) using a sound damping element (2a, 2b) and/or a background or reference microphone (9) where a preferably larger external volume (Vx) that acts as a sound damping element (SDE) is coupled to a smaller volume (7) through which the gas diffuses. The coupling is accomplished in such a way that the externally generated sound waves incident upon the photoacoustic detector (3) are adequately attenuated by the larger volume SDE without adversely affecting diffusion of the gaseous species of interest through the smaller volume for measurement by the detector. Preferably this is accomplished by coupling the larger SDE volume to the smaller gas diffusion volume by a long and thin pressure channel (6).