Monte-Carlo simulation of neutron transmission through nanocomposite materials for neutron-optics applications

Nanocomposites enable us to tune parameters that are crucial for use of such materials for neutron-optics applications. By careful choice of properties such as species (isotope) and concentration of contained nanoparticles, diffractive optical elements for long-wavelength neutrons are feasible. Nanocomposites for neutron optics have so far been tested successfully in protonated form, containing high amounts of H-1 atoms, which exhibits rather strong neutron absorption and incoherent scattering. At a future stage of development, chemicals containing H-1 could be replaced by components containing more favorable isotopes, such as H-2 or F-19. In this note, we present results of Monte-Carlo simulations of the transmissivity of various nanocomposite materials for thermal and very-cold neutron spectra. Our simulation results for deuterated and fluorinated nanocomposite materials predict the losses due to absorption and scattering to be as low as 2%, as well as the broadening of the beam cross section to be negligible.