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 thic k composite material. Other traditional techniques, such as X-ray and therm al neutron radiography (TNR), do not meet FNRs capabilities in this area. F NR is also capable of detecting flaws and moisture in composite materials s ignificantly greater than 25 mm thick and can penetrate all of the material s that X-rays and TNR cannot. The FNR images are produced directly during e xposure; the neutrons create recoil protons, the protons activate a scintil lator screen, and the converted images can be viewed within minutes after e xposure. Some results of FNR images of composite material produced at Argon ne National Laboratory-West-FNR Facility (14.3 MeV) are presented and its i maging techniques are discussed along with their resolution limitations. (C ) 1999 Elsevier Science B.V. All rights reserved.