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Multi-Purpose Diffractometer Detector Mount

Installed on the Swiss-Norwegian beamline at the ESRF

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.

SCD Detector Mount labelled

Right: Diffractometer detector mount installed on Swiss-Norwegian beamline at the ESRF.

Below: Illustration of degrees of freedom on diffractometer detector mount.

SCD Detector Mount installed on SNBL beamline at ESRF