Simulation of a rotating neutron moderator

Abstract

This concept study demonstrates numerically the neutronic properties of a rotating neutron moderator, a device designed to moderate neutrons from a primary source and to emit the neutrons preferentially in a plane within a narrow energy band. The guiding principles are that a narrow energy band is achieved by cooling the moderator to cryogenic temperatures while the directionality and emitted neutron energy are attained by rotating the moderator at an appropriate angular velocity. Proof-of-principle simulations using GEANT4 demonstrate that the number of neutrons emitted at the desired energy and direction from the rotating moderator is about 60 times higher than that emitted by a static room temperature moderator of the same geometry.