TEX-2 is a conventional neutron four-circle-diffractometer which has been optimised for texture investigations on different types of polycrystalline material (fig.1). Texture is defined as the orientation distribution of all crystallites of a polycrystalline material with respect to a well known sample orientation. The importance of a texture is given by two facts. First the anisotropy of polycrystalline materials influences their behaviour with thermomechanical processing, such as forging, extruding, rolling annealing etc.. Depending on the crystal structure, each individual crystal that forms the polycrystalline aggregate shows anisotropic properties and consequently the orientation distribution of the crystallites has a great influence on the anisotropy of the whole material.
Secondly more than 90% of all crystalline materials have a preferred orientation of their crystallites.Thus, texture is of great importance with respect to properties of polycrystalline structural and functional materials such as alloys, ceramics and semiconductors. Furthermore, from textures of geological samples important conclusions can be drawn about geological processes. Therefore, experiments performed at TEX-2 are concerned with a broad variety of different topics. This includes short term projects as well as long term projects with more than 50 samples. Moreover, on one hand the material itself varies from pure metals and alloys (Cu, Ni, Mg, Al, Nb, Fe etc.), to intermetallics (TiAl, NiAl, Fe3Al, Al3Nb, etc.) to composites (Cu-Fe, Al-Cu, Al-Nb, Cu-Nb etc.) and to minerals (hematite, carbonates, galena, chalcopyrite, micas etc.). On the other hand the sample shapes show a broad spectrum from standard geometries (spherical, cylindrical and cubic) to more exotic sample geometries with respect to diffraction experiments by neutrons such as thin wires of some 100 µm up to tubes with 80 mm in diameter. In order to meet all these demands the instrument has a number of special features (numerous sample holders, variable counting grids for pole figure measu-rement, variable wavelength, numerous texture software).