Abstract:
: Nanomaterials can intensively scatter and/or reflect radiation. Such processes and materials
are of theoretical and practical interest. Here, we study the quasi-specular reflections (QSRs) of cold
neutrons (CNs) and the reflections of very cold neutrons (VCNs) from nanodiamond (ND) powders.
The fluorination of ND increased its efficiency by removing/replacing hydrogen, which is otherwise
the dominant cause of neutron loss due to incoherent scattering. The probability of the diffuse
reflection of VCNs increased for certain neutron wavelengths by using appropriate ND sizes. Based
on model concepts of the interaction of CNs with ND, and in reference to our previous work, we
assume that the angular distribution of quasi-specularly reflected CNs is narrower, and that the
probability of QSRs of longer wavelength neutrons increases if we increase the characteristic sizes of
NDs compared to standard detonation nanodiamonds (DNDs). However, the probability of QSRs of
CNs with wavelengths below the cutoff of ~4.12 Å decreases due to diffraction scattering on the ND
crystal lattice. We experimentally compared the QSRs of CNs from ~4.3 nm and ~15.0 nm ND. Our
qualitative conclusions and numerical estimates can help optimize the parameters of ND for specific
practical applications based on the QSRs of CNs.
