Development and Characterization of a High-Energy Neutron Time-of-Flight Imaging System

Los Alamos National Laboratory has developed a prototype of a high-energy neutron time-of-flight imaging system for the nondestructive evaluation of dense, massive, and/or high atomic number objects. High-energy neutrons provide the penetrating power, and thus the high dynamic range necessary to image internal features and defects of such objects. The addition of the time gating capability allows for scatter rejection when paired with a pulsed monoenergetic beam, or neutron energy selection when paired with a pulsed broad-spectrum neutron source. The Time Gating to Reject Scatter and Select Energy system was tested at the Los Alamos Neutron Science Center's weapons nuclear research facility, a spallation neutron source, to provide proof of concept measurements and to characterize the instrument response. This paper will show results of several objects imaged during this run cycle. In addition, results from system performance metrics, such as the modulation transfer function and the detective quantum efficiency measured as a function of neutron energy, characterize the current system performance and inform the next generation of neutron imaging instrument.