Once you have mounted your specimen, it is time to position it.
Turn on the X-ray and Live-Image view and move the specimen into the field of view. The center of rotation must be at the center of the field of view, so the X axis must equal 0. To do this, click on the XS field in the CNC toolbar at the bottom of the screen and enter 0.
Next, move your specimen towards the tube until it fills the field of view (FOV). If you cannot see anything, click and drag your cursor in the field to select a region of interest (ROI), creating a red box. The contrast will be adjusted to the values of the pixels within that ROI. Move your specimen as close as possible without cutting anything off. You must rotate your sample 360º to be sure everything stays in the FOV. The closer your specimen is to the tube, and larger it appears, the higher resolution your scan will be (smaller voxel size) as your specimen is magnified. Be aware of where your specimen is in the chamber so that it doesn't collide with the tube. If you find that you cannot get your specimen close enough, you may need to disable the Collision Protection.
Once you have a satisfactory position, you must save it. Click the gear icon that says "Save" in the CNC portion of the toolbar and select "Acquire Position."
Note that setting up a position for a Multiscan works slightly differently.