VIVALDI—A thermal-neutron laue diffractometer for physics, chemistry and materials science

Abstract

Abstract VIVALDI is a Laue diffractometer based on a cylindrical image-plate detector that will accept a variety of standard and adapted sample environments for fast single-crystal experiments in physics, chemistry and materials science. By using the single-crystal Laue technique with a large solid-angle detector and a thermal neutron beam, the two-dimensional projection of a large volume of reciprocal space of small-unit-cell materials can be seen in a single exposure. Complete structural data can thus be obtained in a time shorter by one to two orders of magnitude than for a monochromatic experiment, with only a modest loss in precision. The dramatically shortened data-acquisition time allows structural and magnetic phase transitions—which often result in complex incommensurable structure—to be observed and followed in detail as a function of temperature or pressure. VIVALDI is scheduled to be in routine operation by the end of 2001.