13.01.2021Theta Consult

Theta Consult

Neutron System for Moisture Measurement

Moisture content measurement system LB 350, manufactured by Berthold, is mainly used in applications where conventional sensor technologies are not applicable because of the conductivity or the chemical properties of the material being measured. “For continuous humidity measurement of solids, the LB 350 uses the neutron deceleration method. It uses the effect of neutron scattering as a result of the interaction of high-energy (fast) neutrons with the nuclei of hydrogen atoms in the material being measured”, the Process control department explained.

The measurement system is based on a source emitting a cloud of fast neutrons. After their interaction with the water molecules in the material being measured, the decelerated neutrons are measured with a special detector that is sensitive to only slow neutrons. Since the number of slow neutrons corresponds to the hydrogen content, the neutron technology is a reliable technical solution for measuring the moisture content of a product.

 “Neutron technology does not depend on the chemical or physical bonds between the water molecules in the measured volume”, commented Mariela Mladenova, a specialist in the field. “It is not affected by temperature, pressure, conductivity, color, pH value, electrolyte content or different particle sizes. Through it, even the content of deep-frozen water can be accurately estimated” the company experts added.

Measurement through the LB 350 system is accomplished by installing a bunker probe inside the tank or a surface probe against the wall of the vessel with the product being measured, depending on the specifics of the application.


The surface probe is mounted directly on the outer wall of a bunker. It is capable to irradiate up to 20 mm thick steel walls. However, the best measuring accuracy is achieved by using Berthold’s specifically designed mounting frame, which is installed in an opening in the wall. The mounting frame is extremely robust due to the wear-resistant ceramics surface and allows for a quick and easy installation of the probe.


The probe is mounted in a dip pipe made from steel or ceramics. Typically, this dip pipe is inserted in the outlet section of the bunker, so that the probe is fully surrounded by bulk material. Due to the optimum position of the probe inside the material flow, a highly representative measurement is achieved.

The LB350 system has proven it’s reliability and extremely accurate operation in multiple hard applications, including moisture measurement of sand int concrete or glass industry, as well as humidity determination of coke and sinter mixtures.