SAXS – the Rise of a Globally Recognized Technique

“X” – the indicator for X-ray

The capital “X” – the letter synonym for “roentgen” rays (X-rays) – was defined by Wilhelm Conrad Röntgen in 1895 for the first time upon the identification of these new and invisible rays. Since then X-rays have proven their irrevocable value in many fields. SAXS is a special structure analysis technique using X-rays as their radiation source to investigate unknown structures and materials. 60 years ago Anton Paar entered the field bringing the first compact small-angle X-ray camera to the market. Learn more about the innovations of SAXS and the major role Anton Paar played in them.

The discovery of X-rays in 1895 marked the start of a new era. This discovery by Wilhelm Conrad Röntgen not only represented the beginning of modern radiology but also the later use of radiation for the structure analysis of a wide range of materials. He was the first to define the concept of X-rays known today and gave the big “X” its meaning as a synonym for X-rays. In 1912 the discovery of X-ray diffraction by Max von Laue established the rapid development of the area. With this method, William Lawrence Bragg and his father William Henry Bragg determined the structure of e.g. cooking salt (NaCl), diamonds, and other materials, and related the resulting scattering images to the atomic distances of the material structure. They derived the well-known Bragg equation from these investigations, which represents the relation between the angle of incidence of the X-ray, the atomic-plane distance, and the wavelength of the X-ray:

The classical X-ray structure analysis was thus invented and entered into all areas of research and science from medicine to material research.

Image 1: Scattering image of a thin film sample

Even one of the greatest discoveries of humankind, the decoding of the human genome by Watson and Crick – the DNA double helix, would not have been possible without X-ray diffraction.

Along with the fundamental discoveries of the characteristics of X-ray radiation came also the industrial use and development of instruments. Radiology was introduced into medicine, and a wide range of apparatuses and methods were developed to investigate inorganic and organic materials, which had not been possible until then.

A further milestone in the development of the X-ray method was the appointment of Otto Kratky (1902–1995) as a full professor for Physical Chemistry at the University of Graz in 1946. He began to expand the field of small-angle X-ray structure analysis (SAXS). His scientific career began in Germany, where he worked together with noble laureates such as Otto Hahn.

SAXS (small-angle X-ray scattering) – the standard for structural analysis

Image 2: Model of globular protein (3D envelopes) based on SAXS data

Otto Kratky’s name is closely connected with X-ray diffraction, and especially with small-angle X-ray scattering (SAXS). He is regarded as the “pioneer of small-angle X-ray scattering” and thus made Graz an internationally recognized center in this field. He invented and developed the first compact small-angle X-ray camera, the Kratky camera. In the same way as with X-ray diffraction the scattered X-rays are detected upon passing the respective sample material in the Kratky camera.

It is essential to note that the sample material no longer needed to be available in crystallized form and that the sample could also be measured without destruction. With this new camera, macromolecules like proteins, lipids, and biological cell structures could be investigated in a new and brilliant way.

Small-angle X-ray scattering (SAXS) together with the first Kratky camera has since then established itself as the standard method for the investigation of macromolecules (for example: proteins, enzymes, antibodies) which cannot be crystallized, and they still form the main pillar of structural analysis.

Anton Paar – a contributor to the worldwide success of SAXS

A main contributor to the worldwide success of the SAXS method and the Kratky Compact Camera (KKK) was Anton Paar. As so often, it was a lucky break which brought Anton Paar into the game. Ulrich Santner (former senior CEO and now member of the Board of Directors) got in contact with an assistant of Otto Kratky who had the challenging task to develop a mechanical step switching system  for the control and automation of the Kratky camera, a significant step towards time-saving measurements. Ulrich Santner had a keen sense for future-oriented new technologies and brought the production of this part of the Kratky camera to Anton Paar. The then small company Anton Paar had a very good reputation in mechanical manufacturing and started producing and selling the Kratky camera in 1957. Hence, Anton Paar entered the field of developing and manufacturing analysis instrumentation at that date.

  • First commercial small-angle X-ray scattering camera by Otto Kratky, built by Anton Paar

  • Automation of the mechanical step counter
    Significant time-saving step towards automated X-ray measurements

     

  • Kratky compact camera (KKK)

    Main features:

    • Unique collimation system
    • Torsion-free cast brass body forming the vacuum chamber
    • Flexible mounting of different detector types on the housing
    • 3-point adjustment

     

  • SAXSess

    Main features:

    • Integrated X-ray optics for highly intense, monochromatic X-rays
    • Modern 2D detector
    • Pinhole option (point collimation) for anisotropic samples
    • Modern data acquisition and evaluation software (SAXSquant™, PCG)
  • Launch of SAXSess mc²

    Main features:·

    • Integrated SAXS system on a compact platform
    • TrueSWAXS™– for simultaneous measurements from small to wide angles in one single run
    • VarioStage with GISAXS extension for screening of solids, multi-directional sample positioning, and GISAXS studies
    • ASX autosampler for up to 192 liquid samples
  • SAXSpace

    Main features:

    • All-in-one sample chamber with built-in alignment stage
    • SmartSAXS –several beam lines connected to a single X-ray source
    • TrueFocus – fully automatic self-alignment of components with X-ray beam
    • Stagemaster feature – automatic recognition of used sample stage and automatic system configuration

     

  • SAXSpoint

    Main features:

    • Compact home lab beamline providing high flux and spectral purity
    • Combined dual X-ray source (Cu and Mo)
    • Scatterless beam collimation for very low background radiation
    • Latest detection technology (EIGER/HPC technology)
  • SAXSpoint 2.0

    Main features:

    • Integration of MetalJet source – for highest X-ray flux available for laboratory systems
    • Additional WAXS detector module in the sample chamber
    • Wide range of temperature-controlled sample stages
    • Advanced SAXSanalysis data evaluation software

A diamond jubilee – 60 years of innovation in X-ray analysis at Anton Paar

In this year’s anniversary, Anton Paar launched SAXSpoint 2.0, a new, advanced small-angle X-ray scattering system onto the market. This device is equipped with the most up-to-date optics, detection system, and automation and evaluation software. Compared to the beginnings when the adjustment and calibration of the X-ray camera often took days, now the adjustment of the system components occurs fully automatically at the push of a button.

60 years have already passed and SAXS instruments have developed from purely manual measurement devices and data analysis to highly innovative, fully automatic, and compact laboratory beamlines. These instrumental innovations continuously allow users to enter new application fields and investigate materials which would not have been possible several decades ago. Moreover, the use of the SAXS method is not restricted to experts any more. It has evolved to a standard structure analysis technique in many application fields.

Curious minds are triggering innovation in X-ray analysis. For this reason Graz University of Technology and Anton Paar invite you to

SAXS eXcites,
the International SAXS Symposium 2017,
from September 26 to 27, 2017
in Graz, Austria,

which will bring together globally recognized key scientists, young scientists, and attendees from complementary fields.

Anton Paar still shapes the future of SAXS instrumentation.
Inventive talent and an insight for future needs are the basis for offering exciting high-end SAXS equipment at the cutting edge of science.

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