Running STXM IV: the essentials

We use a coordinate system where $+Z$ is the downstream direction (the direction the X rays travel), $+X$ is the outboard direction (towards the NSLS control room), and $+Y$ is up to the ceiling.

The inside of the microscope is pictured in Fig. 2.1. You can think of the microscope as having three distinct subassemblies: the zone plate/order sorting aperture (ZP/OSA) assembly, the specimen stage, and the detector stage. In normal use the ZP remains at a fixed position, while the distance from it to the OSA can be adjusted using the ZOSA motor. The specimen stage is moved around with the XSTG, YSTG, and ZSTG motors, and piezo scans are done with the XPZT and YPZT positioners. The detector(s) and visible light microscope are moved using the XDET, YDET, and ZDET positioners.

Figure 2.1: Photo of the inside of the STXM IV chamber. The ``French'' photodiode is indicated as D1. Other labeled items are the visible light microscope VLM, the alignment laser Laser, the photodiode PD, the piezo stage Piezo, and the vacuum snout Snout.

Two programs handle most of the control of the microscope. The SM program provides a graphical user interface for most operations; example screen layouts from this program are shown in Figs. 2.2-2.5. The program sm_script (see Sec. 2.10) is used to do sequences of microscope operations with no user intervention.

Figure 2.2: The general layout of the STXM IV program SM, and the Custom Scan menu.

Figure 2.3: The SM program motor move menu.

Figure 2.4: The SM program detector menu.

Figure 2.5: Alignment in the SM program is done by picking Alignment from the File menu. You can then position detectors etc., or you can also register the current Z position as the correct x-ray focus for this specimen at this photon energy. If you record this focus, you must also save the alignment file for future reference as well.