Neutron Backscatter Technique

What is Neutron Backscatter Technique?

The Neutron Backscattering Technique is based in the property of Hydrogen-rich materials to slow down efficiently a neutron beam. The interaction of neutrons with matter depends on its energy and of course on the properties of the target.


How does Neutron Backscatter Technique work?

The Neutron Backscattering Technique is based on the fact that hydrogen-rich objects are media where fast neutrons can reach thermal energies in a more efficient way (less collisions) than in targets composed by heavier nucleair.

Neutrons carry no charge, therefore, can travel through many centimetres of material without any interaction with electric fields of electron or nuclei. They can be stopped by direct collisions with nuclei. Interestingly, the best materials for slowing down fast neutrons and increasing their chances of being absorbed are those which contain lightest nuclei, i.e. hydrogen nuclei. This is because very light neutrons exchange momentum and energy best with particles of about the same size (proton are only nuclear particles having the same size as neutrons). Eventually fast neutrons (in the range between 0.5 to 11 MeV) lose most of their energy and come to thermal equilibrium with their environment. They are called slow or thermal neutrons and the process of slowing down are called “moderation” or “thermalisation”. These neutrons are on average possess a kinetic energy of 0.25 eV at room temperature.

Where Neutron Backscatter Technique is applied

Neutron backscatter technique has been successfully used for plant troubleshooting and for optimising on-line processes in petroleum refineries, gas processing installations and chemical plants in Malaysia and nearby region. Its main applications are to determine level or interface of materials, and detect sludge deposits in various types of process vessels, storage tanks and pipes. In addition, it also used to measure the moisture presence in bridge concrete, vessel insulator and water taken by trees.