Crystal samples for data collection at the CMCF should be prepared in compatible bases and containers. Since beamline CMCF-ID has an ISARA sample changer and CMCF-BM a Stanford Automated Mounting System (SAM) sample changer, there are slightly different container requirements which are described here.
The sample changers should be used whenever possible and require sample and container information in MxLIVE.
Sample Mounts
Bases and pins should be purchased, prepared and maintained with care. Pins that are not secure in their bases may slide out and interfere with the sample changer or cause centering problems. Rusted or bent sample mounts need to be avoided and debris and hardened glue should not be present on the outside of the bases or pins.
While any solid-metal magnetic-compatible goniometer bases may be used, the best performance is found with B5-SPINE type with pins affixed with glue or epoxy sold by Molecular Dimensions or Mitegen. Other bases, including reusable bases, are accepted but may present issues during full automation.
18 mm mounts are required when using the sample changers and strongly recommended. Plastic mounts should not be used.
Containers
The ISARA sample changer on CMCF-ID accepts only Universal Pucks (Uni-Pucks). The SAM sample changer on CMCF-BM accepts Uni-Pucks and SSRL-style cassettes. Please allow beamline staff to load containers into the sample changers for you; this is part of the beamline setup time and generally occurs during the first hour of your beamtime.
NOTE: Hampton Research Uni-Pucks labeled below 200 (eg: HR00199) are not compatible with the SAM automounter. If you have one of these pucks, please contact Hampton Research to exchange it.
Obtaining Mounts & Containers
Sample mounts and handling tools, Uni-Pucks and shipping dewars can be obtained through a number of suppliers, including MiTeGen, Crystal Positioning Systems, Molecular Dimensions and Hampton Research. A limited number of loops and bases may be borrowed from the beamline for on-site users only.
If it is your first time using the Uni-Puck system, several of the companies offer Universal Puck starter kits containing the required accessories. Although regular users are encouraged to invest in a set of Uni-Pucks and accessories, the CMCF has a limited supply available for lending. Please contact beamline staff to discuss borrowing items.
The Robotic Sample Handling Newsgroup & Information Forum maintains a list of containers & mounts supported by beamlines worldwide. Additional information is also maintained about the Uni-Puck Project. The SAM Hardware Page has detailed information about SSRL-Style Cassettes which can be used on CMCF-BM.
Powder Diffraction Samples
Automounting of capillary mounted samples allows for remote PXRD on the CMCF-BM beamline using the SAM automounter. The total length of of the sample from base to tip is ideally around 23 mm, and must not exceed 25 mm (corresponding to a capillary of maximum length ~20 mm). Samples should be checked for appropriate sizing using an 18 mm cryo-pin tong to ensure compatibility with robot gripper. SSRL cassettes and Uni-Pucks provide more clearance than the gripper tongs, and should not be used as an indicator of sample compatibility for automounting. Capillaries (typically polyimide tubing with an OD below 0.8 mm) should be selected to provide sufficient stability during rotation and secure mounting within a compatible base. The use of tack to secure the capillary is allowed provided that it fits within the gripper tongs. Glue may also be used to secure the sample but must be fully hardened and must not obstruct the sample base..
Other Samples
Use of any non-standard sample containers or mounts not described here must be discussed with beamline staff and described in your research proposal. If approved, the beamline configuration may need to be adjusted. In such cases, additional resource and scheduling considerations may be required.