ADVANCED ENERGY-RESOLVING IMAGING DETECTORS FOR APPLICATIONS AT PULSED NEUTRON SOURCES

NOVA Scientific, Inc. proposes a Phase IIB SBIR program to further develop, refine, and commercialize a compact solid-state epithermal neutron imaging detector based on microchannel plates (MCPs), having (1) high detection efficiency well into the epithermal neutron energy range, and (2) the flexibility of having an externally-mounted pixelated electronic readout mated directly onto a hermetically-sealed MCP neutron detector ‘tube’. As a result of these developments, these devices will be able to perform energy-resolved neutron detection and imaging at pulsed neutron sources, detecting individual neutrons with a spatial resolution of 25-50 μm and with ultrafast timing resolution of ~100 ns for epithermal neutrons. The pulsed structure of the new and more powerful neutron beams coming online enables measurement of neutron energies through the time-of-flight (TOF) method. The unique capability of MCP detectors to measure the energy of each detected neutron provides a capability to conduct experiments across a very broad neutron energy range simultaneously – encompassing epithermal, thermal down to cold neutron energies. Simultaneous detection of multiple Bragg edges, for example, can enable highly useful measurements in crystallographic structure, strain, phase, texture, and compositional distribution. The proposed enhancements in MCP epithermal neutron response resulting from this program, combined with a separate DOE STTR Phase IIB for NOVA to commercialize larger area (>100 cm2) vacuum-sealed and tileable square format cold and thermal neutron-sensitive MCP imaging detectors, could complement or potentially even replace the large array detectors currently implemented at large neutron scattering facilities. Work at Argonne National Laboratory’s Atomic Layer Deposition (ALD) group, guided by NOVA, has continued its excellent progress in the Phase II program, enhancing the sensitivity of NOVA”s MCP cold and thermal neutron detectors well into the epithermal neutron energy range. Using atomic layer deposition (ALD), we continue to refine the application of submicron oxide films of Hafnium, Tantalum, and Samarium along the inner microchannel walls of the detector. In Phase IIB, we will conduct additional neutron testing and full characterization of ongoing improvements to the MCP detectors, working with the neutron facilities (SNS/HFIR) and staff of the Detector Group at Oak Ridge National Laboratory. Moreover, our recent marketing studies suggest that successful commercialization of epithermal neutron-sensitive MCP detectors will require that we provide a ‘user-friendly, turnkey’detector system. Our newly developed epithermal MCPs will be sealed into an image tube, which will have the unique feature of having an externally mounted imaging readout capable of ultrafast event time-tagging – thus dispensing with cumbersome and unwieldy vacuum equipment for active pumping of the detector and readout. Finally, we include in the Phase IIB a new task not previously proposed in Phase II, enabled by the energy range enhancement of NOVA’s MCP-based neutron imaging detectors. We will assess the integration into a ‘benchtop’ system, of NOVA’s epithermal imaging detector with highly intense compact and portable neutron generators, which have recently advanced in capability. If successfully developed and refined, this integration could finally make available true portable neutron imaging and radiography for non-destructive evaluation (NDE).