The experimental selection of the distance between the sample and the window in a photoacoustic FT-IR experiment is shown to be an important parameter when one is optimizing the interferogram intensity. We have experimentally demonstrated the advantages of selecting a small distance rather than the full boundary layer thickness required to ensure complete conversion of thermal to pressure signal at the sample surface. The minimum volume of the sample chamber is a controlling factor in the optimization of the experiment. In this report we demonstrate the value of minimizing sample chamber volume through controlling sample thickness while pointing out the need for care when doing so.
