Imaging methods utilize transmission of neutrons and X-rays to obtain visual information on the macro- and microscopic structure and/or inner processes of a given object. Both types of radiation can pierce through several cm thick materials, so the inner structure of even a bulky object can be characterized in a non-destructive way. The interactions between the penetrating radiation and the matter, however, result in the attenuation of the transmitted neutron or X-ray beam. Imaging (i.e., the formation of a contrast pattern) is made possible by detecting different amounts of radiation reaching different points on the screen. Users are offered by radiographic (2D imaging) or tomographic (3D imaging) datasets depending on both the tasks to be fulfilled and the available technical possibilities. The different interaction of the two types of radiation (X-ray – with electron shell, neutron – with nucleus) gives complementary information. X-ray imaging is a widely used basic method compared to neutrons, usually with a rather good spatial resolution. However, neutrons can be used well for materials made up of elements with low atomic numbers that cannot be examined, or can only be poorly examined, with X-rays. In addition, neutron imaging is particularly sensitive to hydrogen content. Its disadvantages compared to X-ray imaging are the lower spatial resolution, longer exposure times, and the temporary activation of the irradiated object. The triad of spatial resolution, exposure time and field of view should always be optimised.

Neutron & x-ray imaging -radiography & tomography

Imaging

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