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Large detector for small particles

Especially interesting for
  • dimensional nanometrology
  • medicine
  • biotechnologies

In cooperation with PTB, the Swiss company Dectris has developed a vacuum- compatible version of its X-ray detector “Pilatus” to attain even photon energies below 5 keV. This device allows, for example, experiments for the size determination of nanoparticles to be carried out with Small-Angle X-ray Scattering (SAXS) also at the absorption edges of the light elements calcium, sulphur, phosphor or silicon with high dynamics and spatial resolution. This is essential especially when it comes to investigating biological samples..

Small-angle X-ray scattering image of a multilamellar liposome sample, recorded at a photon energy of 3 keV with a vacuum-compatible Pilatus detector at PTB's FCM beamline at BESSY II.

At PTB's laboratory at the electron storage ring BESSY II, the size of nanoparticles or the dimensional parameters of nanostructured surfaces are determined by means of SAXS with synchrotron radiation. With the new detector, the measurement capabilities have decisively improved, especially in the case of low-scattering samples and of elementspecific investigations. This is applied, for instance, within the scope of projects of the European Metrology Research Programme (EMRP), where complex biological nano-objects and nanoparticles are dimensionally characterized in complex biological matrices using SAXS measurements with synchrotron radiation. Hereby, work is currently focused, among other things, on the microvesicles that occur in all body fluids. Medical engineers – e.g. at the Amsterdam Medical Center, which is significantly involved in one of the projects – are willing to exploit the size distribution of these microvesicles for the early detection of diseases.

The development of the new hybrid pixel detector “Pilatus” mainly focuses on the spatial division of the detector modules with a total of one million pixels, which are now in vacuum, and a part of the highly complex detector electronic unit which, for cooling purposes, has to be operated under ambient conditions. Operating the detector modules in vacuum allows X-ray experiments to be performed also at a low photon energy which would be too strongly absorbed under ambient conditions. The first vacuum-compatible Pilatus detector device worldwide, which consists of 10 modules and, at a pixel size of 172 μm, exhibits a total surface of 17 cm ∙ 18 cm, was successfully commissioned at PTB's laboratory at BESSY II in June 2012. In cooperation with the Helmholtz-Zentrum Berlin and the Research Centre for Natural Sciences of the Hungarian Academy of Sciences, the first SAXS images of a multilamellar liposome sample were recorded at a photon energy of 3 keV at the Four-Crystal Monochromator (FCM) beamline in PTB's laboratory at BESSY II. Liposomes are membrane vesicles composed of a lipid bilayer with structural sizes in the nanometre range; they are important in the fields of pharmacology, biotechnologies and cosmetics. In the future, it is planned to use the detector also for wide-angle scattering (WAXS), small-angle scattering (GISAXS) in reflection under grazing incidence, and other X-ray techniques.


Michael Krumrey
Department 7.1 Radiometry with Synchrotron Radiation,
Phone: +49 (0)30 3481-7110

Scientific publication

T. Donath, S. Brandstetter, L. Cibik, S. Commichau, P. Hofer, M. Krumrey, B. Lüthi, S. Marggraf, P. Müller, M. Schneebeli, C. Schulze-Briese, J. Wernecke: Characterization of the PILATUS photon-counting pixel detector from 1.75 keV to 60 keV. J. Phys. Conf. Ser. 425, 062001 (2013)