NNSA plays a vital role in the U.S. governments efforts to prevent, respond, and counter to a terrorist or other adversary with a nuclear or radiological device. NNSA does this by providing expertise and practical tools used to counter nuclear threats. To support its functions and foundational capabilities across nonproliferation, counterterrorism, and emergency response mission areas, NNSA needs advanced sensors and instrumentation that may be used to rapidly identify threats and get the information needed to counter them. The proposed research directly addresses the DOE/NNSAs mission needs with the development of a portable, high spatial resolution, combined neutron/ X-ray radiography detector. The envisioned detector would be capable of high sensitivity imaging of fast neutrons, thermal neutrons, and high energy X-rays. The detector could also be operated at high framing rates, and our proprietary algorithms would permit data analysis for materials identification purposes. The detector will employ a high performance, structured, solid-state sensor that will simultaneously provide high detection efficiency for various radiation types over a wide range of energies while maintaining the desired high spatial resolution. The goal of the proposed Phase I is to demonstrate our design feasibility. During Phase I, we will conduct (1) sensor design and simulations, (2) develop protocols for large area sensor manufacturing, and fabricate sensors for Phase I studies, (3) assemble a prototype detector and characterize its performance in relevant radiation environment/s, and (4) demonstrate feasibility through imaging and data analysis to validate materials identification capability. We will work closely with the DOE program officials for translating this transformative technology into their application space, and into commercial space. A large area detector capable of high sensitivity, high spatial resolution for neutrons and X-rays is needed for numerous applications in homeland security, nondestructive testing, military hardware testing, and numerous applications in medical fields. From a pure scientific point of view, such a detector will be well suited for determining atomic positions and displacement parameters of light elements (such as hydrogen), next to heavy metals in advanced materials or new drugs, and will be an ideal solution for studying magnetic structures, phase transitions, disorder, and local structure phenomena using crystal diffractometry, Laue diffraction, and proteing crystallography instruments. Research in each of these areas will directly benefit the public by accelerating the development of new drugs, novel materials, and systems, all of which have a direct impact on health care, quality of life, addressing the nations future energy needs, and it will expand our technology base.