The intensity of beta rays is weakened according to the mass of the penetrated layer. This weakening allows determining the basis weight of nearly all materials. Different isotopes (Krypton, Strontium, Promethium) are used for different weight ranges. With coating processes, the application quantity can be determined as weight difference using several sensors.
Except for very low weight ranges, beta transmission is the universal method for measuring basis weight. However, certain radiation protection requirements must be complied with due to the weak radioactive isotopes.
The density of the product web can also be determined in combination with thickness sensors. If the density of the measured product is known, however, and remains constant, the material thickness can also be determined via the basis weight.
Measurement of basis weight (mass per unit area) / thickness /density
Transmission of beta rays
The weight monitoring and control system measures the weight continuously, without contact, destruction-free and on moving product. The measurement is based on the…