Influence of Surface Structures on the Entry of Neutrons into Moderating Material

Enhancing the output of (cold) moderators in neutron sources is a topic of highest interest since the very beginning of employing neutrons for research. Emphasis and effort has been focused so far on amplifying useful neutron flux by optimizing the output-side of moderators. Preliminary numerical studies have indicated that similar structuring as established for the output side boosting flux out of a moderator could be beneficial at the input side byfirst letting neutrons enter the moderator volume more efficiently. Indeed, these predictions have been found correct in the course of preliminary experiments performed at PSI's NEUTRA facility. Thecurrent paper is a sequel to Thomsen et al., 2014 reporting on continued analysis and modelling efforts.