Xcalibur

X-ray diffractometer that has a proven track record earned over many years.



Xcalibur single-crystal X-ray diffractometer from the Rigaku Oxford Diffraction division has a proven track record earned over many years. From the first Xcalibur installed in 1999, this instrument has well-deserved reputation for providing great data quality, with outstanding system reliability. Xcalibur system employs Enhance fine-focus X-ray sources, which can be either molybdenum or copper radiation and are factory pre-aligned to give maximum intensity. Coupled with the either the highly sensitive and dynamic Eos, Atlas or CCD S2 detectors, this system offers great data quality to meet the ever-increasing demands of the modern day laboratory environment.

Benefits:

  • Outstanding reliability the systems have been kept up-to-date with latest technology electronics and detectors
  • Access to two wavelengths gives the laboratory ultimate flexibility for research
  • Easy to operate system with user friendly software
  • Single source Xcalibur systems can benefit from an on-site upgrade to a dual-source Gemini configuration at any later date

Features:

  • Enhanced fine-focus X-ray sources with monocapillary optics
  • Easy dual-source Gemini upgrade
  • High precision kappa 4-circle kappa goniometer
  • Accepts full range of S2 CCD or HPAD detectors
  • New protection cabinet with motion enable system
  • Fully compliant with EU safety directives
  • Single, high voltage generator
  • Enhanced diagnostic firmware for improved service and support
  • Powerful external PC for instrument and experiment control
  • CrysAlisPro – Powerful, user-friendly software, with optional AutoChem2.0 for fully-automated structure solution and refinement


  • Crystallorgaphy
  • Density measurements
  • X-ray sourse with Cu anode lets you study protein molecules and determinate absolute structure
  • S2 CCD detector
  • PILATUS 200K HPAD detector
  • 4-Circle cappa goniometer: very open geometry, up to 30% faster data collections than 3-circle, high precision, motorised detector distance: 40 -150 mm

See the “Specification” part

Crystals are regular arrays of atoms, and X-rays can be considered waves of electromagnetic radiation. Atoms scatter X-ray waves, primarily through the atoms’ electrons. Just as an ocean wave striking a lighthouse produces secondary circular waves emanating from the lighthouse, so an X-ray striking an electron produces secondary spherical waves emanating from the electron. This phenomenon is known as elastic scattering, and the electron (or lighthouse) is known as the scatterer. A regular array of scatterers produces a regular array of spherical waves. Although these waves cancel one another out in most directions through destructive interference, they add constructively in a few specific directions, determined by Bragg’s law.
X-ray diffraction results from an electromagnetic wave (the X-ray) impinging on a regular array of scatterers (the repeating arrangement of atoms within the crystal).
X-rays are used to produce the diffraction pattern because their wavelength is typically the same order of magnitude (1–100 angstroms) as the spacing between planes in the crystal. In principle, any wave impinging on a regular array of scatterers produces diffraction, as predicted first by Francesco Maria Grimaldi in 1665. To produce significant diffraction, the spacing between the scatterers and the wavelength of the impinging wave should be similar in size. For illustration, the diffraction of sunlight through a bird’s feather was first reported by James Gregory in the later 17th century. The first artificial diffraction gratings for visible light were constructed by David Rittenhouse in 1787, and Joseph von Fraunhofer in 1821. However, visible light has too long a wavelength (typically, 5500 angstroms) to observe diffraction from crystals. Prior to the first X-ray diffraction experiments, the spacings between lattice planes in a crystal were not known with certainty.
The idea that crystals could be used as a diffraction grating for X-rays arose in 1912 in a conversation between Paul Peter Ewald and Max von Laue in the English Garden in Munich. Ewald had proposed a resonator model of crystals for his thesis, but this model could not be validated using visible light, since the wavelength was much larger than the spacing between the resonators. Von Laue realized that electromagnetic radiation of a shorter wavelength was needed to observe such small spacings, and suggested that X-rays might have a wavelength comparable to the unit-cell spacing in crystals. Von Laue worked with two technicians, Walter Friedrich and his assistant Paul Knipping, to shine a beam of X-rays through a copper sulfate crystal and record its diffraction on a photographic plate. After being developed, the plate showed a large number of well-defined spots arranged in a pattern of intersecting circles around the spot produced by the central beam. Von Laue developed a law that connects the scattering angles and the size and orientation of the unit-cell spacings in the crystal, for which he was awarded the Nobel Prize in Physics in 1914.