At Neutron Insights we not only use our high knowledge of particle detectors and ionizing radiation to apply radiography and emission tomography and neutron detection to different fields of industry, but we also naturally carry out different simulations that help us develop each of our solutions more efficiently.
FORGED RODS IN CONCRETE COLUMNS
If the concrete is well made, the slab should not rust due to the basic environment generated by the concrete. However, in the event of cracks or fissures, oxidation or corrosion could occur, reducing the useful section of the structural element. To detect these effects by neutron emission, we simulate metal rods embedded in a concrete column and irradiate them from different positions with neutrons of energies compatible with portable generators.
We simulated 4 steel rods in a concrete column, two with a layer of iron oxide (Fe2O3) of 4 mm which reduces their effective cross-section. Thanks to the increased interaction of neutrons with oxygen, the rust is clearly identified with our technology. In backscatter images, both rods and the oxide layer are distinguished without the detector being behind the object. In addition, the radiograph of transmission at one second irradiation allows to estimate the cross-section of the rods, detecting possible signs of corrosion or oxidation.
Simulation of a concrete column containing 4 steel rods of 4 cm diameter, two of them with 4 mm of iron oxide. Simulated image of the section of the concrete column with rods obtained by retro-dispersion, that is, the neutrons which have been bounced out 180º after irradiation are detected. Steel rods and oxide coating are identifiable due to different interaction with neutrons.
STEEL PIPE WITH DIFFERENT THICKNESSES
The simulated steel pipe containins air inside, with an internal radius of 10 mm and an external radius decreasing in different steps from 20 mm (corresponding to 10 mm wall thickness) to 13 mm (corresponding to a wall thickness of 3 mm). The radiography of the object was simulated both in the open air and in the field, in two different situations: on a concrete block and on a ground block.
The radiographic image by transmission after 1 second of irradiation of the buried pipe in concrete and ground shows a very similar behaviour. The main difference between the two situations is the higher moisture content of the soil and, therefore, higher hydrogen and oxygen content, both elements with high neutron absorption power. In both situations the buried pipe is distinguished by its different wall thicknesses and even, especially in the case of concrete, the different densities are seen to inform the inside of the pipe, in this case a hollow containing air.
