Single-crystal diffraction at ES2 can be performed on the basis of sample rotation (PHI) with a maximum range of ±40 deg. with a fast detector (PILATUS3 S 1M) in transmission geometry. Alignment of the sample in the DAC is accomplished by placing the sample into the rotation center of the PHI rotation. A single vertical rotation axis sitting on a xyz stage stack serves as the point of reference for the sample position. The sample is positioned onto the rotation axis with a second xyz stage on top of the PHI axis. Alignment of the detector with respect to the rotation center is not necessary since the detector is located in transmission geometry. Rough positioning, final positions, sample-to-detector distance and geometric parameters of detector orientation are accomplished by step scans from a NIST ruby ball (and/or CeO2) standard.
Workflow of single-crystal diffraction measurements: First, the crystal (or DAC) is mounted and properly aligned either optically or using the x-ray beam. Then, a preliminary check is performed to evaluate the crystal quality and find the proper parameters for data collection with the help of quick scans. Subsequently, the diffraction data are collected using proper step sizes, exposure periods and phi ranges. Then, diffraction peaks are harvested, and indexing were applied to get the lattice parameters, the bravais lattice, and UB matrix. Integrating of reflections and applying a series of corrections provide a dataset (in .hkl format) suitable for structure determination and refinement.
