Fiedler Team
Instrumentation for synchrotron beamlines for structural biology
Robotic sample mounting system for protein crystals (MARVIN)
Previous and current research
EMBL is designing, building and will operate three beamlines for structural biology at the PETRA III synchrotron radiation source. The facilities will be dedicated to the leading techniques for X-ray-based structural research of biological samples: small angle X-ray scattering (BioSAXS beamline) and macromolecular crystallography (MX1 and MX2). Construction includes the provision of the X-ray optical elements, experimental endstations, vacuum system, control system, data acquisition system, technical infrastructure and parts of the civil engineering, for which our team provides expertise in X-ray optics, precision mechanical engineering, robotics, control soft ware and electronics.
By 2009, most of the principal optical elements had been constructed and already partly manufactured, including the high-heatload monochromators and cooling systems, Kirkpatrick-Baez focusing optics with adaptive bimorph mirrors, deflection mirrors for angular separation of adjacent canted undulator beams and cooled UHV slit systems. Our work focuses on the selection, customisation and integration of mechanics, control electronics and control soft ware. In addition, our activity ranges from the development of instruments from scratch to the performance of relevant validation experiments and commissioning of instrumentation for user experiments. Examples of this are the construction of a focusing double multilayer monochromator (MLM) for the existing BW7a beamline at the DORIS storage ring, which serves as a test platform for developments for the PETRA III beamlines (see also Hermes group, page 103) or the development of nanometer resolution slits.
Another important project is the development of a completely updated version of a robotic sample mounting system for protein crystals, MARVIN (see figure). The system is characterised by its high sample storage capacity, high sample mounting speed, improved geometry and maintainability. It has been commissioned at the BW7b beamline at DORIS and will be now cloned for the MX beamlines at PETRA III.
As a side project, a new high precision goniometer axis with sub-micrometer precision has been built. These elements are now integrated into a soft ware-based modern control system which allows for a heterogeneous control environment and provides distributed access and monitoring. This is a prerequisite for the planned remote-controlled user experiments at the PETRA III beamlines.
Future projects and goals
In the next year our efforts will concentrate on:
- Installation and commissioning of the new beamline elements so that first users can be received;
- integration of control hardware and soft ware into a generic control architecture;
- further automation of alignment, sample handling and data acquisition;
- rapid feedback on positional and intensity variations of the incident beam;
- follow-up or start of a number of selected instrumental development projects (e.g. robotic sample changer for MX, beam conditioning unit);
- continuation of our investigations in MX with multilayer radiation.
In the longer term, time-resolved structural biology studies down to the microsecond will be performed on the new beamlines. We plan to develop the instruments and the level of synchronisation that are necessary, as well as exploring the possibilities and requirements for biological imaging research at PETRA III.