A high-pressure single-crystal-diffraction experimental system at 4W2 beamline of BSRF.

Information on the structural evolution of materials under high pressure is of great importance for understanding the properties of materials exhibited under high pressure. High-pressure powder diffraction is widely used to investigate the structure evolution of materials at such pressure. Unfortunately, powder diffraction data are usually insufficient for retrieving the atomic structures, with high-pressure single-crystal diffraction being more desirable for such a purpose. Here, a high-pressure single-crystal diffraction experimental system developed recently at beamline 4W2 of Beijing Synchrotron Radiation Facility (BSRF) is reported. The design and operation of this system are described with emphasis on special measures taken to allow for the special circumstance of high-pressure single-crystal diffraction. As an illustration, a series of diffraction datasets were collected on a single crystal of LaB using this system under various pressures (from ambient pressure to 39.1 GPa). The quality of the datasets was found to be sufficient for structure solution and subsequent refinement.