High resolution x-ray characterization of periodically domain-inverted nonlinear optical crystals

A high-resolution triple-axis diffractometer has been used for the structural characterization of periodically domain-inverted nonlinear optical crystals of KTiOPO4 and LNbO3. Striations have been revealed in high strain-sensitivity multiple-crystal topographs of the domain-inverted regions of both these samples and these are dominated by orientation contrast. The combination of high-resolution reciprocal-space mapping and topography has shown that the extended diffraction streak in the q[210] direction for domain-inverted LiNbO3 originates from the "minutely misoriented structure" which is related to the original configuration of dislocations. The reason for the generation of the structural imperfections via the domain-inversion processing is interpreted in terms of the converse piezoelectric effect

Gold potential of the Dalradian rocks of north-west Northern Ireland : prospectivity analysis using Tellus data

The Dalradian terrane in the north-west of Northern Ireland is prospective for orogenic vein-hosted gold mineralisation with important deposits at Curraghinalt and Cavanacaw. New geochemical and geophysical data from the DETI-funded Tellus project have been used, in conjunction with other spatial geoscience datasets, to map the distribution of prospectivity for this style of mineralisation over this terrane. A knowledge-based fuzzy logic modelling methodology using Arc Spatial Data Modeller was utilised. Four main groups of targets were identified, many close to known occurrences in the Lack - Curraghinalt zone and others in prospective areas identified by previous investigations. Additional targets are located along west-north-west trending linear zones at the eastern end of the Newtownstewart Basin and to the north of the Omagh-Kesh Basin. These zones may be related to major structures linked to a westward extension of the Curraghinalt lateral ramp which is regarded as an important control on the location of the Curraghinalt deposit