Halogen mass flow rate detection system

This abstract discloses an improvement within an oxygen-iodine chemical laser in the form of a mass flow rate detector for rapidly, accurately, and reliably detecting the mass flow rate of iodine into the resonant cavity of the laser. A mass flow rate detector has an absorption cell to which either an inert gas or an iodine-inert gas mixture is passed. An electromagnetic beam of preselected wavelengths in the bound-continuum absorption region is passed through the absorption cell while either the iodine-inert gas mixture or only the inert gas is therein. By measuring the intensity of the beam passing through the absorption cell molecular absorption can be utilized for determining the concentration of the iodine in the iodine-inert gas mixture. From this value the mass flow rate of the iodine passing through the absorption cell and into the resonant cavity of the laser is determined.