Hi everyone, Yes Im a newbie here so forgive me if I dont ask the question correctly. I am trying to understand how to determine the minimal and maximum path length based on gas absorption. I know this is based on Beer Lamberts Law but I am not sure which formulas to use and the order to use them. I appologize but I am not degreed in physics, but I have been a hobbist in spectroscopy and gas analysis for about 2 years. In my thoughts I figured tat a minimal the following parameters must be considered. 1. Path Length 2. Gas (O2-760nms, 1% by volume)(range is .5% to 20%) 3. Beam Diameter 4. Pressure 5.Temperature 6. Tansmission So if I did not ask correctly, I know the gas Im trying to measure, but not sure how to calculate what path length would be acceptable based on the sensitivity and range. I am willing to do the work, just looking for some guidance here. Thank you in advance.