Fiedler Team
Synchrotron instrumentation for structural biology beamlines at PETRA III
Design of the P14 experimental endstation with sample mounting system MARVIN.
The Fiedler team focuses on the selection, customisation and integration of mechanics, control electronics and control software for X-ray based structural biology research.
Previous and current research
EMBL has designed, is building, and operates three beamlines for structural biology at the PETRA III synchrotron radiation source on the DESY campus in Hamburg. The facilities will be dedicated to the leading techniques for X-ray-based structural research of biological samples - small angle X-ray scattering (SAXS), and macromolecular crystallography (MX). For the construction and operation of these facilities, our team provides expertise in X-ray optics, precision mechanical engineering, robotics, control software, and electronics. We are in charge of X-ray optical elements, and the experimental endstations, vacuum system, cryogenic system, control system, data acquisition system, technical infrastructure, and parts of the civil engineering.
In 2011, all three beamlines came into operation and first experiments have been successfully carried out. The remaining instruments necessary for the basic optical set-ups have been installed and commissioned. Notably these were the P13 horizontally deflecting mirror pair, several UHV slits and beam position monitor sets, PLC-based vacuum control, an automatic sample changer for SAXS, a high-precision diractometer for MX, experimental tables for all endstations, and the first of three beam conditioning units. In addition, the cryogenic supply system for the beamline endstations has been prepared and the beamline control network has been designed and mostly implemented.
Examples for complete in-house developments are the construction of a focusing double multilayer monochromator for the BW7a beamline at the DORIS storage ring which serves as test platform for instruments for the PETRA III beamlines (see also Hermes group) or the development of nanometer resolution slits or the development of white beam monitors in collaboration with DESY. Another on-going project is the development of a robotic sample mounting system for protein crystals named MARVIN (see figure). The system is characterised by its high capacity, sample mounting speed, and flexibility and is integrated into a software-based control system which allows for a heterogeneous control environment and provides distributed access. A prototype is in user operation on the BW7b beamline at DORIS and adapted versions are under installation on the MX beamlines at PETRA.
Future projects and goals
- Establishing stable user operation on all PETRA beamlines in parallel.
- Adaptive focusing mirror optics and control of beam size and shape.
- Integration of detector supports and the MARVIN system.
- Integrating beamline elements into a global instrument protection system.
- Further automation of alignment, sample handling and data acquisition
- Rapid feedback on positional/intensity variations of the incident beam.
- High flux polychromatic optics for P12.
- Crystallisation plate screening with the MX robotic sample changer.
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 for these kinds of experiments and explore the possibilities for biological imaging research at PETRA III.