Study of the liquid state. Containerless environments and applications using neutrons scattering techniques

Orateur : Viviana CRISTIGLIO (Institut Laue Langevin, Grenoble)

Aerodynamic levitation is an effective way to suspend samples which can be heated with CO2 lasers. Aerodynamic levitation combined with laser heating has proved to be powerful and versatile technique for studying th e structure of high-temperature liquids using neutron and X-rays scattering. Other advantage of this method is that it is possible to supercool hot liquids several hundreds of °C below their melting point to study metastable states. The simplicity and compactness of the device makes it possible to integrate it easily in different kinds of experiments. In addition, all types of materials can be used, including metals and oxides. The integration of aerodynamic levitation at synchrotron and neutron sources provides powerful tools to study the structure and dynamics of molten materials. An overview of the existing levitation techniques and the instruments at ILL and ESRF in which this technique was integrated will be presented. The results of structural investigation with neutrons of aluminates oxides obtained will be shown. Molecular dynamics simulations made to support the experimental data and complementary X-rays data will be also mentioned. In the second part of this seminar, the major characteristics, performances and new directions of the D16 instrument will be exposed, as well as recent examples of performed experiments. D16 is one of ILL’s two-axis diffractometer at low momentum transfer and it is demanded for a wide range of systems in biology, physics and material science. In terms of Q-space and Q-resolution, D16 nicely fills the gap between the small angle instruments and classical diffractometers. The instrument geometry offers a variable vertical focusing which allow working in reflectivity or diffraction mode in an intermediate Q-range (0.01-2.5 Å-1). A high resolution SANS setup with 1% wavelength resolution and diffraction is routinely used.

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