Very Large Area Microchannel Plate Neutron Detectors

NOVA Scientific, Inc., teamed with the Detector Group of the ORNL Neutron Sciences Directorate (NScD) of Oak Ridge National Laboratory, proposes to construct very large area Microchannel Plate neutron detectors. Larger format (20 cm square) tileable detectors will serve an exceptionally broad range of government agencies from neutron scattering detectors for DOE to nuclear material panel detectors for NNSA. The collaboration benefits from NOVAs knowledge and development of neutron-sensitive MicroChannel Plate (MCP) detectors and the Oak Ridge electronics groups detector expertise in high event rate and low noise detectors. The proposed program represents a remarkable step forward in neutron detection.Past neutron detectors have been constructed using 3He gas tubes, which offer both high thermal neutron detection efficiency as well as excellent discrimination between neutrons and interfering gamma rays. However, the sources of 3He gas are being quickly expended, severely constraining a variety of neutron detection applications such as scientific instrumentation, forcing end-users to seek alternative detection methods. NOVA has developed small, neutron-sensitized, solid-state MCP detectors that exhibit neutron detection efficiencies and gamma rejection levels approaching that of the conventional 3He gas tubes. This program will construct much larger MCP modules (400 cm2) and even larger arrayed systems, utilizing the novel Oak Ridge readout technology. The product developed will be a large area neutron imaging detector with spatial resolutions & lt; 1 mm, good timing resolution, low noise, high flux capabilities, and excellent detection capabilities for cold and thermal neutrons with archival data for centroid averaging. Phase I work successfully integrated the neutron-sensitive MCPs fitment with the large area electronic readout and demonstrated the functionality of the combination with neutrons without issues. Phase II will further develop the highest neutron efficiency MCPs available and assemble the hardware suitable for demonstration of high spatial resolution with time tagging and high flux capabilities. Prototype modules will be arrayed into larger panel detectors. New neutron scattering facilities, located at the High Flux Isotope Reactor and the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, provide much higher flux than existing sources, translating into much higher detector flux requirements. Such instrumentation will require better position resolution and rate capability than available with existing technologies, along with the continuing requirements of gamma rejection and stability. These characteristics of this large detector will be a critical step in development of a solid-state converter to replace 3He detectors. NOVA has provided a significant number of state- of-the-art neutron imaging detectors at national laboratories and leading universities within the USA. This program will leapfrog current neutron detector performance and will serve to maintain US leadership in materials research and neutron technology.