Measuring wafer orientation using a 5-axis cradle
Cadmium tungstate (CdWO4) wafers are used as scintillation crystals to detect gamma rays. Waveguides can be fabricated in the crystals using laser cutting followed by gap filling with highly reflecting materials. These are then coupled to a large area CMOS sensor to form an X-ray imaging system. Under some conditions it was found that cracks could be seen to propagate from the cut edges and that the crack propagation was dependent upon the direction of laser cutting.
The 5-axis Eulerian cradles on the X’Pert³ MRD (XL) series diffractometers and the 5-axis sample stage on the Empyrean, together with their high-resolution 2theta and omega goniometers, are designed for precision, flexibility and ease of use. Furthermore the combined rocking curve and triple axis (TA) PreFIX optic enables the hands-free change-over from high-speed peak finding routines to high-precision peak position measurements. The orientation of a single crystal cadmium tungstate wafer was obtained, using a combination of rapid scans that could easily be formulated into batch routines.