Cover Publication of "Journal of Applied Crystallography" for JCNS-3

08 October 2024

A joint study undertaken by researchers from JCNS-3 and the Institute of Crystallography at RWTH Aachen University has been selected for the cover of the October issue of the Journal of Applied Crystallography. Scientists at the Friedrich-Alexander University Erlangen-Nuremberg (FAU), the Max von Laue-Paul Langevin Institute (ILL), and Freiberger Compound Materials (FCM) also collaborated in the study entitled "Promise of GaAs 200 in Small-Angle Neutron Scattering for Higher Resolution" (Magerl, A., et al., Applied Crystallography, 57.5, (2024)).

In neutron scattering (and similarly in X-ray scattering), structural problems on an atomic or molecular scale are often observed. However, key questions, particularly those related to practical applications, can also be addressed on the mesoscopic scale and beyond. Small-angle scattering was developed to enable research in this field. With the usual small-angle diffractometers based on the pinhole camera principle (without optical elements), objects up to 2 µm can be visualised. The Bonse-Hart method (BH), a special small-angle technique, uses two perfect crystals and achieves sizes of up to 30 µm. Today, only structurally perfect Si crystals are used. However, if Si is replaced by GaAs in the BH method, sizes of up to 300 µm can theoretically be imaged. In an initial experiment, a size limit of 210 µm was achieved.

Structures of this size can, of course, also be studied using other methods, for example with a light microscope. However, there are many questions that should be examined complementarily with a different type of radiation. Neutrons, with their unique scattering contrasts for different elements, their isotope sensitivity, and their sensitivity to magnetic phenomena, are particularly attractive in this context.

Original publication:

The promise of GaAs 200 in small-angle neutron scattering for higher resolution
A. Magerl, H. Lemmel, M. Appel, M. Weisser, U. Kretzer, M. Zobel
Journal of Applied Crystallography, Vol. 57, Part 5, October 2024