Responsible for the facility

Main research areas

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Main view of facility

Description of GRAINS:

The GRAINS reflectometer is designed to investigate surfaces and interfaces between "soft" matter and fluids using reflection of thermal neutrons. The system under investigation has a horizontal plane (vertical plane of reflection). The initial neutron beam coming from the cold moderator in the reactor core is collimated in a horizontal plane using a system of split apertures. To control the angle at which it falls on the sample (0.5-25 mrad), a special neutron mirror is used - a deflector. Since the deflecting mirror reflects only thermal neutrons (wavelength > 0.05 nm), it also performs the function of separating the thermal neutron beam from fast neutrons (wavelength < 0.05 nm) that are used as a source of the background. After reflection from the sample plane, the scattered beam is detected by a large-area position-sensitive detector. Position sensitivity allows to analyze the scattered beam in two directions (in the vertical and horizontal planes) and thus determines the implementation of the so-called complete 3D reflectometry, including:
1) Analysis of total specular reflection (measurement of the dependence of the reflectivity of the system at the maximum point, as a function of the momentum transfer modulus);
2) Analysis of non-specular reflection (measurement of diffuse scattering in the vertical plane as a function of the momentum transfer vector);
3) Analysis of small angle scattering at grazing angles (GISANS) (measurement of diffuse scattering in the horizontal plane as a function of the momentum transfer vector).

Main characteristics

Thermal neutron flux on the sample	~ 1-2 х106 c-1 cm-2
Wavelength range	0.05 – 1 nm
Measured reflection angle range	2 – 20 mrad
Scattering vector range	0.05 – 3 nm-1
Resolution	< 5%

Sample environment:

References

1. V. Avdeev, V.I. Bodnarchuk, V.I. Petrenko, I.V. Gapon, O.V. Tomchuk, A.V. Nagorny, V.A. Ulyanov, L.A. Bulavin, V.L. Aksenov, "Neutron time-offlight reflectometer GRAINS with horizontal sample plane at the IBR-2 reactor: Possibilities and prospects", Crystallography Reports, 2017, Vol. 62, Issue 6, pp. 1002-1008. DOI: 10.1134/S1063774517060025
2. M.V. Avdeev, A.A. Rulev, V.I. Bodnarchuk, E.E. Ushakova, V.I. Petrenko, I.V. Gapon, O.V. Tomchuk, V.A. Matveev, N.K. Pleshanov, E.Yu. Kataev, L.V. Yashina, D.M. Itkis, "Monitoring of lithium plating by neutron reflectometry", Applied Surface Science, 2017, Vol. 424, pp. 378-382. DOI: 10.1016/j.apsusc.2017.01.290
3. V. Gapon, V.I. Petrenko, L.A. Bulavin, M. Balasoiu, M. Kubovcikova, V. Zavisova, M. Koneracka, P. Kopcansky, H. Chiriac, M.V. Avdeev, "Structure analysis of aqueous ferrofluids at interface with silicon: neutron reflectometry data", Journal of Physics: Conference Series, 2017, Vol. 848, Issue 1, pp. 012015. DOI: 10.1088/1742-6596/848/1/012015
4. Gapon I.V., Petrenko V.I., Soltwedel O., Khaydukov Yu.N., Kubovcikova M., Kopcansky P., Bulavin L.A., Avdeev M.V. Crystallization of aqueous ferrofluids at the free liquid interface investigated by specular and off-specular x-ray reflectometry. IOP Conf. Series: Journal of Physics: Conf. Series 994 (2018) P. 012008. http://dx.doi.org/10.1088/1742-6596/994/1/012008
5. Petrenko V.I., Gapon I.V., Rulev A.A., Ushakova E.E., Kataev E.Yu., Yashina L.V., Itkis D.M., Avdeev M.V. Studies of electrochemical interfaces by TOF neutron reflectometry at the IBR-2 reactor. IOP Conf. Series: Journal of Physics: Conf. Series 994 (2018) 012006
6. Nagornyi A.V., PetrenkoV.I., Rajnak M., Gapon I.V., Avdeev M.V., Dolnik B., Bulavin L.A., KopcanskyP., Timko M., Particle assembling induced by non-homogeneous magnetic field at transformer oil-based ferrofluid/silicon crystal interface by neutron reflectometry, Applied Surface Science, V. 473, 2019, P. 912-917 https://doi.org/10.1016/j.apsusc.2018.12.197
7. V. Avdeev, A.A. Rulev, E.E. Ushakova, Ye.N. Kosiachkin, V.I. Petrenko, I.V. Gapon, E.Yu. Kataev, V.A. Matveev, L.V. Yashina, D.M. Itkis, On nanoscale structure of planar electrochemical interfaces metal/liquid lithium ion electrolyte by neutron reflectometry, Applied Surface Science, 486 (2019) P.287-291. https://doi.org/10.1016/j.apsusc.2019.04.241.
8. Tropin T.V., Karpets M.L., Kosiachkin Ye., Gapon I.V., Gorshkova Yu.E., Aksenov V.L. Evaluation of fullerenes C60/C70 layers in polystyrene thin films by neutron and X-ray reflectometry. Fullerenes, Nanotubes and Carbon Nanostructures, 29(10) P.819-824, (2021), https://doi.org/10.1080/1536383X.2021.1901276