Installed on the Swiss-Norwegian beamline at the ESRF
Independent detector support frame & sample goniometer on common platform.
Detector support with 4 degrees of freedom.
Common platform with 5 degrees of freedom.
Huber Kappa sample stage mount with 3 degrees of freedom.
Counterweight safety system to protect detector from mechanical failures.
In conventional single crystal diffractometers, the X-ray detector is attached via
a rigid arm to a rotary table. The diffraction angle (2θ) is then defined by the
mechanical movement of the rotary table. With the advent of area detectors, the size
and weight of X-ray detectors has increased dramatically. It has therefore become
more and more difficult to mount heavy and bulky detectors on a rotary arm. The situation
is particularly difficult when using synchrotron radiation, since the horizontal
polarisation of the incoming X-ray beam favours a vertical diffraction plane.
The alternative solution is to mount the detector on a separate support frame, but
to place the detector support and the sample goniometry on a common platform. Precision
mechanics are essential in order to allow the detector to be positioned accurately
and reproducibly relative to the sample. This alternative solution was realised by
IDT for the Pilatus 2M detector installed on the Swiss-Norwegian beamline at the
ESRF. The detector is bulky and weighs 42kg, but it is nevertheless possible to position
the center of the detector at a diffraction angle of up to 45° (at the closest position)
and to vary the sample-to-detector distance from about 150mm to almost 1000mm. The
support frame for the detector and the sample goniometry are both mounted on a common
granite base, which in turn can be aligned relative to the incoming beam using a
system of jacks and slides with 5 degrees of freedom. A total of 15 motorised movements
allow the sample and the detector to be precisely positioned and aligned relative
to the synchrotron beam.
Right: Diffractometer detector mount installed on Swiss-Norwegian beamline at the
ESRF.
Below: Illustration of degrees of freedom on diffractometer detector mount.
