2019, Elyutin, N. O., Abov, Y. G., Lvov, D. V., Tyulyusov, A. N., Львов, Дмитрий Владимирович, Тюлюсов, Антон Николаевич

© 2019, Pleiades Publishing, Ltd.Dynamic neutron diffraction on perfect InSb crystals is analyzed theoretically both under conditions of predominantly potential scattering and under conditions of predominantly resonant scattering. Attention is given primarily to the effect of anomalous neutron transmission. A project of an experiment aimed at studying this effect in predominantly resonant neutron scattering via a simultaneous detection of reflected and transmitted beams and secondary gamma rays is proposed. It is shown that such an experiment may be performed in beams from high-flow reactors.

2022, Dzheparov, F. S., Gulko, A. D., Elyutin, N. O., Lvov, D. V., Shestopal, V. E., Джепаров, Фридрих Саламонович, Львов, Дмитрий Владимирович

Studies in spin dynamics of disordered media and multiple ultra-small angle neutron scattering are considered. The experiments were carried out on unique installations designed in ITEP laboratory of neutron physics: beta-NMR spectrometer and universal neutron diffractometer. The main attention is paid to random walks in disordered systems and ultra-small angle neutron scattering (USANS) on objects with space correlations in positions of scatterers. Synthesis of concentration expansion, semi-phenomenological theory and numerical simulations produced satisfactory description of the nuclear polarization transfer within disordered 8Li-6Li spin subsystem in LiF single crystal. The theory of USANS starts from eikonal approximation for the scattering amplitude, which (a) reproduces the phenomenological Moliere-Bethe theory for the observable neutron angular distributions for uncorrelated random positions of scatterers, and (b) gives a possibility to take into account their spatial correlations. © 2022 World Scientific Publishing Company.