Micro-focus single crystal X-ray diffractometer

• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: Funded in 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 512666989

The proposed X-ray diffractometer is a device for determining the atomic structure of single crystals both at room conditions and at high-pressures and temperatures. The machine is a replacement for two existing traditional single crystal diffractometers for which replacement parts are no longer available. The new device would have a more intense X-ray source so that it will be possible to determine unit cell parameters and crystal structures for single crystals as small as 8-10 micrometres, about an order of magnitude smaller than traditional diffractometers. The diffractometer would be located at the Bayerisches Geoinstitut (BGI) of the university of Bayreuth. Researchers at the BGI investigate the physics and chemistry of the Earth’s interior, mainly using experimental methods that often involve the application of high pressure and temperature technology. The role of the new diffractometer would be two-fold. The first would be to characterise newly discovered crystalline phases, the majority of which would be produced at the BGI in high pressure and temperature experiments. Such crystals generally formed through pressure instigated phase transitions and can most often be recovered to room pressure and characterised. As BGI scientists push the frontiers of achievable conditions, however, recovered crystals are increasingly smaller, and to characterise their crystal structures requires more intense and focused X-rays. Secondly, BGI scientists are also focused on determining how pressure and temperature affect the densities of mineral phases and their elastic properties, knowledge of which is necessary for understanding mantle dynamics and interpreting seismic velocity variations inside the Earth. This can be achieved through in situ X-ray diffraction measurements of single crystals compressed inside a diamond anvil cell. A laser heating system would also be developed so that high temperatures can be applied to single crystals inside the diamond anvil cell while X-ray diffraction measurements are being performed. In order to develop these two applications a custom diffractometer is required having two different configurations.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Mikrofokus-Einkristall-Röntgendiffraktometer
• Instrumentation Group: 4010 Einkristall-Diffraktometer
• Applicant Institution: Universität Bayreuth
• Leader: Professor Dr. Daniel J. Frost