P212121

We traveled to the Advanced Photon Source this past weekend and rocked out on beamline 21 for 24 hours. The beamline had robotics for crystal mounting and although we did not use them for auto-mounting it was neat to see the set up. If you are interested in robotic mounting at a synchrotron near you then this page is worth exploring.

I picked a couple of bits of information about the robotics on this particular beamline.

1) Robots do not work well with certain pins. Although the 18 mm Hampton-style pin is recommended as the universal standard you need to be sure you select the right one. The Hampton Copper Magnetic HT was not allowed while the Hampton Copper Magnetic ALS HT was fine. The reason was due to the ‘upper lip’ that is present which differs between these two pins. ‘Upper lip’ meaning the ledge that is present before the pin tapers to meet the vertical copper pin. A picture can of these pins can be seen here (view full size – the left pin is not allowed while the center pin is fine). Molecular dimensions also has caps and pins that can be used.

2) Hampton caps (the plastic part that fits over the pin) were not allowed and instead had to use caps by Molecular Dimensions. The reason was being due to the consistency of length in Molecular Dimension caps. Personally, I have never noticed a difference in the lengths of the caps from Hampton.
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The crystal sits on a pin which is in a puck. The puck is placed in a container filled with liquid nitrogen. The robotic arm removes the pins from the puck, which is located inside the large container on the right side of the above picture.

I really enjoy reading and hearing stories about crystallography. A brief history of crystal mounting leading up to robotics is wonderfully covered in a paper (pdf) by Cele Abad-Zapataro.

Stephen also wrote a great post discussing his exciting times at a synchrotron awhile back.