Ponente
Descripción
Neutron imaging is a non-intrusive inspection tool of interest in many applications. The most employed technique involves thermal neutrons, in most cases from a nuclear reactor, that offer an excellent contrast for light elements, mainly hydrogen, thus complementing gamma- and X-rays. However, all these have serious limitations when dealing with large samples. In these cases, only fast (MeV) neutrons can provide images with reasonable contrast, which is related to the generally low neutron interaction cross sections of fast neutrons. This makes fast neutron imaging a promising inspection modality for many practical problems.
At DONES, both thermal and fast neutrons can be delivered to the R160 experimental room making it suitable for neutron imaging. In the case of thermal neutrons, the expected flux of about 1e4 n/cm2/s on the sample for a L/D=200 is a few order of magnitude lower than that available at nuclear reactors; hence, while possible and interesting as complement for conventional radiography, it will not be very competitive. On the contrary, the outstanding fast neutron flux of 1e10 n/cm2/s is 3 orders of magnitude higher than that of state-of-the-art facilities such as the NECTAR facility at the FRM-II reactor, which would make DONES a world leading facility in the development and use of fast neutron radiography, allowing for even high resolution fast neutron tomography. Furthermore, the availability of the TOF-DONES neutron time-of-flight facility in R026 opens the door to Fast Neutron Resonance Radiography (FNRR), an innovative technique which adds elemental characterization to the outcome of the conventional fast neutron imaging.
This contribution will discuss the basics of neutron imaging and, as an example, the current achievements at the CNA HISPANOS facility on neutron radiography and tomography will be presented. Then, the prospects for the implementation of the different modalities of neutron imaging at DONES will be discussed.
