Filter membrane sample holders for Rotation/Phi stages

//Filter membrane sample holders for Rotation/Phi stages

The Siemens D5000 and Bruker D8 systems we work with have an optional phi-stage that is very useful. It looks and moves like any other rotation stage, but it’s driven by a stepper motor which actually makes it an additional degree of freedom. The user can rotate the sample at a specified rate, position it at a specified angle, or even perform a scan in the phi axis.

We have a client who just took delivery of their D5000 and needed to analyze samples deposited on 25mm Ag filter membranes. Other users have tried a variety of solutions with varying degrees of success so this seemed like a good opportunity to create something that worked better was easier to use.

These stages use a ring of magnets to hold either a cup, transmission attachment, or a dedicated sample holder with a ferrous ring. None of these are a good solution for filters on their own. The prototype shown here uses a steel ring with an Aluminum body. Making the entire holder from steel would be easier, but the Fe in the beam would fluoresce. The filter is held in place from the bottom of the holder to keep it in the plane of diffraction while sacrificing only a small amount of surface area and shadowing at extremely low angled.

We’ve used snap rings with disks, 3D printed plastic, and now these laser-cut acrylic springs to support the membranes. The acrylic springs have made loading and unloading much easier and from what we have seen, they hold up very well through repeated use.