Fiedler Team

Design of the P14 experimental endstation with sample mounting system MARVIN.

The Fiedler team focuses on the construction, customisation and integration of X-ray optics, precision mechanics, robotics, control electronics, cryogenics and control software for synchrotron-based structural biology research.

Previous and current research

EMBL has designed, built and operates three beamlines for structural biology at the PETRA III synchrotron radiation source on the DESY campus in Hamburg. Beamline facilities are dedicated to the leading techniques for X-ray-based structural research of biological samples: small angle X-ray scattering and macromolecular crystallography. Our team provides expertise in X-ray optics, precision mechanical engineering, robotics, control software and electronics and is in charge of the X-ray optical elements, experimental endstations, vacuum system, cryogenic system, control system, data acquisition system, technical infrastructure and parts of the civil engineering.

Recent major projects

All three beamlines reached regular user operation. In preparation for this, it was necessary to install and commission adaptive focusing optics at all beamlines, develop a multi-degree-of-freedom heavy-duty detector stage for the largearea pixel detectors at the MX beamlines (P13 instrument installed) and to develop and install white beam X-ray monitor systems for all beamlines. A cryogenic supply system for the beamline endstations has been installed and is in operation and a two-floor control hutch area with computing infrastructure was set-up in order to allow beamline control and users to perform experiments in a comfortable manner.

Multilayer optics

An ongoing in-house development is the construction of a double multilayer monochromator that is intended to boost the flux density at the P12 SAXS beamline – this enables time-resolved solution scattering experiments in the microsecond range. This instrument has been further developed from a prototype installed at a beamline of the former DORIS storage ring that can preserve the highly increased coherence of the radiation delivered by the PETRA III synchrotron. We are also working on the development of downstream experimental instrumentation with the level of synchronisation necessary for dynamic measurements.


For all beamline facilities, it is important to develop capabilities such as automatic operation and remote access. In this context, a robotic sample mounting system named MARVIN is being developed for the MX applications (see figure). This is characterised by high sample storage capacity, high sample mounting speed and flexibility. It is integrated, like all beamline elements, into a software-based control system which allows for a heterogeneous control environment and provides distributed access. The prototype has been in user operation on the BW7b beamline at DORIS and adapted versions are undergoing installation on the MX beamlines at PETRA.

Future projects and goals

  • Positional and intensity feedback and (active) vibrational stabilisation of the monochromatising optics.
  • Automatic tuning of adaptive focusing mirror optics to varybeam size/shape.
  • Integration of beamline elements into a global instrumentprotection system.
  • Further automation of alignment and data acquisition andintegration with sample preparation/crystallisation.
  • Improved sample observation and positioning at or beyondthe optical resolution limit for microcrystallographic investigations.
  • Exploring preparative or bridging developments for the X-ray freeelectron laser with state-of-the-art synchrotron beamlines.

Physics and Engineering at EMBL