Alternatives to nuclear sensors for on-line web-gauging of weight / thickness measurement

The traditional method for the on-line measurement of extruded / cast films, extrusion coatings, solution and hot-melt coatings and nonwovens has been the use of one or more Beta Transmission Sensors. As the availability of certain isotopes has become uncertain and end-users increasingly are more concerned about the use and disposal of radioactive sources, the desire to find alternative non-nuclear measurement solutions is at an all-time high. Recent improvements in Near Infrared Sensors have expanded their use into traditional beta-gauge applications with a good degree of success. This paper will discuss the web processes for which an Infrared Sensor is becoming a preferred measurement solution.