Fast neutron radiography for composite materials evaluation and testing

Fast neutron radiography (FNR) employs recoil protons produced by energetic neutrons in a hydrogen-rich plastic sheet through elastic scattering. FNR provides distinctive advantages in non-destructive evaluation (NDE) of thick composite material. Other traditional techniques, such as X-ray and thermal neutron radiography (TNR), do not meet FNRs capabilities in this area. FNR is also capable of detecting flaws and moisture in composite materials significantly greater than 25 mm thick and can penetrate all of the materials that X-rays and TNR cannot. The FNR images are produced directly during exposure; the neutrons create recoil protons, the protons activate a scintillator screen, and the converted images can be viewed within minutes after exposure. Some results of FNR images of composite material produced at Argonne National Laboratory-West-FNR Facility (14.3 MeV) are presented and its imaging techniques are discussed along with their resolution limitations.