Process and apparatus for measuring optical density changes and transit times in transparent materials

摘要

A recirculating optical/electronic closed loop feedback process and apparatus in which nanosecond light pulses are triggered by a pulse generator upon arrival of previous signals that have just completed a round trip through the closed loop feedback system. The optical path is comprised of a light source and a detector between which is mounted beam forming optics that guide the light beam from the light source through a transparent vessel having a semitransparent medium therein whose refractive index and/or transparencies are measured. The electronic portion is comprised of a pulse amplifier for amplifying the detected light beam that in turn is repetitively applied to a high rate pulse generator to retrigger the light source through a pulse counter that records the number of signal circulations which pass through the closed loop during a given time to indicate the change of transmissivity of said medium.