Control of basis weight / thickness



The Beta-Sensor determines basis weight and thickness by the attenuation of radioactive rays through the substrate located in the measuring gap.

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 attenuation of rays from a radioactive isotope through the substrate located in the measuring gap. This attenuation in intensity is an indication of the weight of the product.

Product highlights

  • Highest repeatability ofthe measured values
  • Non-contacting measurement
  • Digital signal processingTemperature compensation
  • Source ageing compensation
  • Gap compensation

Customer benefits

  • Material saving
  • Quality assurance
  • Increased production
  • Comprehensive quality documentation

Optimal basis-weight set-point

The correct basis weight is a decisive quality criterion in many process technologies in the textile industry and coating technology. Monitoring, control and logging of this parameter is therefore a decisive process step. The key is to determine the basis weight under the given industrial conditions online and with high repeatability.

In addition to ensuring product quality, an appropriate set-point with narrow tolerances can provide considerable savings in material and energy consumption, achieve process reliability while at the same time increasing production.

Area of application

  • Coating of textiles
  • Carpet coating


  • Krypton-85
  • Strontium 90
  • Gap cleaning

Technical data

Krypton 85
  • Activity 3,0 GBq / 9,62 GBq
  • Measuring range 10 – 1400 g/m²
  • Measuring gap 10 – 100 mm
Strontium 90
  • Activity 500 MBq
  • Measuring rang 100 – 5000 g/m²
  • Measuring gap 10 – 100 mm


Gravimat FMI-15