Studies on a Pulsed Thermal/Epithermal Neutron Source with a Compact Accelerator for Neutron Imaging

A small neutron facility based on a compact accelerator has some advantages over a large facility in terms of accessibility and usability. One of main objects of a compact accelerator neutron source is neutron imaging. Therefore, we performed an optimization study on a pulsed thermal neutron source and an epithermal one based on a compact accelerator in order to use it for thermal neutron imaging and resonance neutron imaging. We have carried out simulation calculations to evaluate the neutron intensity change depending on the moderator size taking into account spatial resolution. The intensities from a small moderator were higher than that from a larger one when compared at the same L/D. However, field of view (FOV) constrained the minimal moderator size. At L/D of 100 and FOV from 10 to 30 cm, the optimal moderator size giving the highest intensity was from 10 to 12 cm.