Universal specimen prealigner

A specimen prealigner for positioning in a preselected alignment a specimen having a peripheral edge that includes a sharp contour transition, the preselected alignment including a selected position and a selected orientation, comprising:

• a specimen holder releasibly holding the specimen at an arbitrary specimen location and orientation and rotating the specimen at a substantially constant angular rate;
• a positioner coupled to the specimen holder moving the rotating specimen such that the peripheral edge of the specimen is detected by an optical scanner, the optical scanner including a light source that directs light toward the peripheral edge of the specimen and an array of light detectors that receive the light after it strikes the specimen, the array of light detectors cooperating with the light source to detect the peripheral edge of the specimen and generate alignment data for moving the positioner such that the peripheral edge of the specimen tracks a subset of the array of light detectors, and the array of light detectors cooperating with the light source to detect the sharp contour transition and generate periphery distance data;
• and
• a scan data processor using the alignment data and the periphery distance data to generate a periphery map of the specimen.