Speaker
Description
Nanodiamond Particles (NDP) are new candidates for neutron reflection. They have a large scattering and low absorption cross-section for low-energy neutrons. Very Cold Neutrons (VCN) are reflected in NDP with large scattering angles while Cold Neutrons (CN) have a quasi-specular reflection at small incident angles. A new scattering process has been added in Geant4 in order to examine the directional reflection of CN in an extraction beam made of NDP layers. Impurities in NDP are responsible for the up-scattered neutrons, especially hydrogen which has a high scattering cross-section. Other impurities are also considered in Geant4 in order to produce a more accurate model of NDP scattering. The new scattering process was used to model possible configurations of target-moderator-reflector in compact sources. A typical beam of 13 MeV proton striking a Beryllium target was chosen. Para-hydrogen is placed as a cold moderator in order to produce CN. NDP are placed around the extraction beam for scattering the CN toward the exit of the beam. The results show that CN exiting the extraction beam can be increased thanks to the implemented NDP layer.
