Magnified neutron radiography with coded sources

摘要

A coded source imaging system has been developed to improve resolution for neutron radiography through magnification and demonstrated at the High Flux Isotope Reactor (HFIR) CG-1D instrument. Without magnification, the current resolution at CG-1D is 80μm using a charge-coupled device (CCD) equipped with a lens. As for all neutron imaging instruments, magnification is limited by a large source size. At CG-1D the size is currently limited to 12mm with a circular aperture. Coded source imaging converts this large aperture into a coded array of smaller apertures to achieve high resolution without the loss of flux for a single pinhole aperture, but requires a decoding step. The developed system has demonstrated first magnified radiographic imaging at magnifications as high as 25x using coded apertures with holes as small as 10μm. Such a development requires a team with a broad base of expertise including imaging systems design, neutron physics, microelectronics manufacturing methods, reconstruction algorithms, and high performance computing. The paper presents the system design, discusses implementation challenges, and presents imaging results. Funding for this effort conies from the U.S. Department of Energy through an Early Career Award out of the Office of Basic Energy Sciences. Part of the research conducted at ORNL 's High Flux Isotope and the Center of Nanophase Materials Science was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. Portions of this manuscript have been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.