High Resolution Digital Imaging Platform for NDE Transient Testing

Neutron radiography using the foil-film transfer method is currently employed for the quantitative evaluation of the geometric and compositional characteristics of nuclear fuel burn-up distribution, visualization of cracks and void formations, fuel location determination, pellet-clad and pellet-pellet gaps identification, and to understand the state of non-fuel component geometries. Although this method is gamma insensitive and provides large area high spatial resolution radiographs, this process takes significant time to produce an image, which is impractical for neutron radiography and/or tomography. A large area digital detector that can simultaneously provide high spatial resolution, rapid response, and can operate in a harsh radiation environment is needed to accomplish these tasks. We are developing a novel solid-state digital imaging detector based on neutron intercepting integrated circuit. This detector offers high sensitivity to thermal neutrons, is insensitive to gamma radiation, has fast temporal response, is able to image highly-radioactive specimens with high spatial resolution, and can withstand intense mixed radiation environments. Low cost modular design and easy scalability to realize very large active areas are its other attractive features. In Phase I, we established the feasibility of developing a solid-state neutron radiography detector through experimental tests conducted at Oak Ridge National Laboratory and at Idaho National Laboratory. The prototype detector demonstrated high efficiency to thermal neutrons, exceptional spatial resolution, insensitivity to gamma background from fuel specimens, and its ability to acquire images in minutes under realistic field conditions. The goal of the Phase II program is to develop a fully functional, large area digital neutron detector. The IC readout circuitry, data acquisition hardware, and software will be developed. The resulting prototype will be thoroughly characterized to demonstrate its sensitivity to neutrons, insensitivity to gamma radiation, high resolution imaging capability, and its ability to operate in a harsh radiation environment under field conditions. Technology commercialization activities will also be undertaken in parallel. The proposed neutron detector applications include non-destructive testing, baggage scanning at entry ports, diffraction studies in support of research in medicine, energy, and transportation at facilities worldwide including at DOEs Spallation Neutron Source (SNS) and at the Los Alamos Neutron Scattering Center (LANCE). The Department of Homeland Securitys (DHS), Department of Defenses (DOD), and DOEs future deployments of radiation detection portal monitors will benefit from the proposed development.