D15 is a diffractometer installed at the thermal inclined beam tube IH4. It can be operated in either the 4-circle geometry or the normal beam geometry and with a wide range of sample environments.

D15 in the normal-beam geometry

  • To compensate for the inclination of the incident beam, the monochromator is tilted to bring the monochromatic beam into the horizontal plane.
  • The sample is a single crystal. Sample environment devices can be a cryostat (as shown here), a furnace, a cryomagnet up to 10 Tesla, a high pressure cell or a combination of these.
  • The sample is rotated through its vertical axis so that some crystal planes can diffract.
  • The detector is rotated and lifted towards the diffracted beam.

When the intensities of a large enough number of Bragg reflections have been collected, they can be used to compute the crystal structure of the sample i.e. to determine the nature and position of its atoms and the magnitude and orientation of its atomic magnetic moments.

  • The monochromator shielding is lifted to show that the inclined monochromator diffracts the incident beam in the equatorial plane.
  • The cryostat is lifted to show the sample position.