Offline Sample Coordinate And Registration System (OSCAR)
The X-ray microprobe at 13-ID-E now includes an offline microscope in the beamline control area to allow users to view samples and select ares for X-ray analysis before putting the sample in the X-ray beam. OSCAR uses a standard Nikon petographic micrsoscope provides adjustable zoom level (5x, 10x, 20x, 50x), lighting (reflected or transmitted light), and polarizing filters. The microscope has both ocular view finders and a high-resolution video camera for seeing the sample images.
Several plastic sample holders are available, and use the same kinematic mounts as used for the microprobe Sample Stage, allowing these mounts to be moved easily from the OSCAR microscope to the X-ray Sample Stage. We have quite a few specialized holders that can hold up to 6 1-inch round thin (or thick) sections, and holders that can hold up to 3 standard microscope slides (see image). For many other types of samples, samples can be affixed to the plastic frames with double-sided tape.
The samples can be moved with the same GUI control that is used to move the sample in the microprobe. This control allows saving any position on the sample mount by name (“Bob’s section, opyx grain 1”), and automatically saves the camera image for each saved position.
Once sample positions are saved for a particular holder with the OSCAR microscope, a simple macro command in the data control system will transfer the coordinates to the beamline Sample Stage, and you’ll be able to drive to every saved position quickly with the sample mounted in the X-ray beam. The transferred positions are good to within 50 microns, so they may need some refinement before starting an XRF Map or XANES analysis, but once you’re in the OSCAR will get you neighborhood.
X-ray Absorption Fine Structure (XAFS)