OCR Text |
Show "----- 11: Corner Cube Reflector ~ Exhaust Flow "--- [J ---/' -' --_...1/ .. . OR .. . Low Pressure Multipass Cell LTDL B •• m---i-·"-"--~.. to Pump Figure 1. Sampling Region Options - In Situ or Extractive Sampling length, the line strength (an intrinsic molecular parameter), and is inversely to the line width. If we solve for the minimum detectable concentration, we fmd ( ) _ 0.001 1t ~VTOT 106 Xmin ppm - .Q. x N(p, T) ( 1) where S = line strength - .Q. = path length N(p, T) = number density 2 ~Vpb ~v pb 2 1/2 ~VTOT = line width =-2- + ( 4 + ~VG) . 2 2 1/2 WIth ~VG = (~VlaCOier + ~VD) 4 |