Large Area Time-of-Flight Detectors for Imaging Science

NOVA Scientific, Inc. proposes a Phase I SBIR program to develop, refine, and ultimately to commercialize, a large format 15 cm x 15 cm solid-state cold, thermal, and epithermal neutron imaging detector based on microchannel plates (MCPs). The imaging detector will be fabricated in a self-contained, hermetically sealed image tube, which does not require active vacuum pumping. This large area time-of-flight (TOF) MCP detector with integrated delay line anode (DLA) electronic imaging readout, will be capable of TOF energy-dispersive neutron imaging, providing very high spatial resolution (~50 µm FWHM) while also providing ultrafast timing resolution (<1 µs) – simultaneously encoding position and wavelength information, hence enabling energy- selective and energy-dispersive neutron imaging. The outstanding capabilities of neutron- sensitive MCP detectors in this imaging context with pulsed neutron sources, have been amply demonstrated in several recent refereed publications with senior neutron researchers. The current 20 MHz requirement across the large 15cm x 15cm area proposed can readily be met by NOVA’s key MCP neutron–converter ‘front-end’ component, which has already been successfully built and demonstrated in this unusually large format. However, at the system level, the MCP electronic readout necessary to capture and properly register MCP output charge pulses is also absolutely critical to realizing the intrinsic MCP performance. The very large detection area for imaging combined with requirements of very high spatial resolution and fast time-tagging severely restricts the type of readout that can be used. The best candidate readout for this demanding application able to be scaled up in format to the 15cm x 15cm format, that can meet the very high spatial and timing resolution requirements, is the well- known cross delay line anode (DLA). A DLA readout approach is the one we propose to employ for this project, which with some modification can be scaled up to the desired 150mm x 150mm area format. NOVA will continue to closely work with the neutron facilities (SNS/HFIR) and staff members of the Detector Group of Oak Ridge National Lab’s (ORNL) Neutron Sciences Directorate, for neutron testing and application requirements.