Fast X-ray scattering measurements on high temperature levitated liquids

We describe a new high temperature environment based on aerodynamic levitation and CO₂ laser heating designed for high energy X-ray diffraction at the ID11 beamline at ESRF. The use of two lasers simultaneously provides a homogeneous temperature and makes it possible to explore the supercooled state with a high degree of control (about 500 °C below the melting point in this work) and to work very close to T_g. The scattered beam is measured over a relatively wide Q-range of 0.5–19 Å^?1 with the ESRF Frelon 2D CDD camera. Using 1-min measurements we obtained good quality structure factors at various temperatures in the liquid and supercooled state of CaAl₂O₄. We also performed time-resolved measurements using an acquisition time of 100 ms and we obtained good statistics even at large Q. The Al–O and Ca–O bond lengths and coordination numbers derived from the calculated pair distribution functions are in good agreement with our previous X-ray and neutron works.