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Methoden und Instrumentierung Poster: Mi., 14:00–16:30 M-P41
Horizontal Reflectometer at the IBR2-Reactor Dubna
V. Lauter-Pasyuk 1,2 , H. Lauter 2
1 TU München, Germany – 2 ILL, Grenoble, France
The IBR-2 reactor is a high-flux long-pulse reactor. After the refurbishment the IBR-
2 reactor will be equipped with a cold moderator, which will be optimized for the
horizontal reflectometer. A long flight-path is available to get a wavelength resolution
of ∼2 % for the interesting regions of the broad wavelength distribution and thus for the
broad q-range. Moreover an inclined flight-path is foreseen, favorable for a horizontal
reflectometer. Direct view on the cold moderator, but not on the core, and full use of
the cold moderator surface allows maximizing the flux. The background can be kept
on a very low level due to experience with the actual reflectometer REMUR. Larmor
precession of the neutrons will be used for angular encoding. This is a new method
[1] which allows to tailor the angular resolution without changing the cross section of
the beam. The two-dimensional detector will be of the same type, which gave recently
interesting results for the fast neutron background.
The scientific case is given by the study of fluid samples, which require a horizontal
sample surface, ranging from surfactants, liquid polymers to biological membranes and
solutions of pharmaceutics. Particular attention will be given to off-specular scattering
and GISANS, so to lateral correlations of the samples in the two orthogonal directions
of the sample plane and with its depth sensitivity. Application of these techniques
gives also access to an extremely broad range of lateral correlations.
The use of polarized neutrons allows also developing magnetic scattering from e.g.
magnetic fluids in TOF within the Larmor precession field at small external magnetic
fields.
The Larmor precession research project has been supported by the European Commission
under the 6th Framework Programme through the Key Action: Strengthening
the European Research Area, Research Infrastructures. Contract n ◦ : RII3-CT-2003-
505925.
[1] H.J. Lauter, B.P. Toperverg, V. Lauter-Pasyuk, A. Petrenko, V. Aksenov, Physica
B 350, e759 (2004)