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Cryogenic sample changer

Phi and Chi axis

  • Phi axis with continuous 360 deg. rotation, up to 2 deg./sec
  • Chi axis with rotation range of 90 deg.
  • Chi axis moves up automatically during sample transfer


  • motor swings in and out
  • rotation range approx 110°

Goniometer head

  • automatic goniometer head with x,y,z translations
  • point & click centering via software

Crystal monitor

  • built-in camera with large LCD screen

Carousel with 19 samples

  • Storage for 19 vials
  • Vials stay in LN2 all the time
  • Small volume, small LN2 consumption rate
  • Very small ice formation rate

The marcsc is an automated sample changing robot for X-ray crystallography. The instrument is fully integrated into the mardtb "desktop beamline", our multi-purpose goniometer. This integration makes the marcsc a compact, robust and very reasonably priced tool for high-throughput crystallography. For more details, please have a look at the specifications.



Designed as a completely integrated package with the mardtb advanced goniostat for single-crystal diffraction, the marcsc is a complete turn-key sample mounting system small enough not to crowd any synchrotron hutch or X-ray laboratory. The automated data collection reduces the fatigue on scientists, and allows testing larger numbers of crystals than previously possible.


Because the marcsc is an attachment to the mardtb, it takes advantage of the convenience of one-click automatic beam alignment. The whole system aligns itself to the X-ray beam automatically and has no realignment headaches or crashing problems of independent robotic arms.


The removable carousel of 19 vials keeps samples safely in liquid nitrogen until they are called by the data collection program. A new carousel can be loaded by the user in just 30 seconds.


Samples are mounted for data collection by a system of computer driven motors. The user can be at the instrument, outside the hutch or X-ray laboratory, or at home!


Optical images of the crystal from the mardtb CCD microscope and a unique image processing algorithm, are used to align the loop in the X-ray beam. An active illumination system ensures constant lighting conditions independent of external light sources.


Samples are mounted into the cold stream directly from a full vial of liquid nitrogen. With no room temperature exposure, crystals are kept safe in the cryogenic environment. The empty vial is replaced in the liquid nitrogen during data collection, and pulled out afterwards to accept the sample directly back into liquid nitrogen.


Sample identification is accomplished with a built-in barcode reader and magnetic caps with 2D barcode and alphanumeric number. The reader supports standard SPINE codes (2D data matrix with 12x12, 14x14 or 16x16 dots). Beware of ink-printed codes, though! While they are easily readable by the bar-code reader, the ink layer greatly reduces the holding force of the solenoid on the goniometer head, impeding safe sample handling.


Simple or sophisticated data collection protocols are all possible with the marcsc computer control. From screening to full data sets, the marcsc can automatically and reliably collect a full carousel of samples worth of data without user intervention. Useful crystal centering images are automatically logged for later verification.


The marcsc cooperates with the mar345 image plate detector, and Rayonix's SX-165 CCD and MX-225 CCD detectors. It also supports a broad range of DECTRIS detectors.


Download the marcsc product brochure and the movie and convince yourself how easy crystal mounting and retrieving can be using the sample changer.

The movie is in mp4 format with 320x240 pixels resolution and uses the H.264 codec.